Editing Neodymium

{{infobox neodymium}}
'''Neodymium''' is a [[chemical element]]; it has [[Symbol (chemistry)|symbol]] '''Nd''' and [[atomic number]] 60. It is the fourth member of the [[lanthanide]] series and is considered to be one of the [[rare-earth element|rare-earth metals]]. It is a [[hard (physics)|hard]], slightly [[malleable]], silvery metal that quickly [[tarnish]]es in air and moisture. When oxidized, neodymium reacts quickly producing pink, purple/blue and yellow compounds in the +2, +3 and +4 [[oxidation state]]s. It is generally regarded as having one of the most complex [[emission spectrum|spectra]] of the elements.<ref>Werbowy, S., Windholz, L. Studies of Landé gJ-factors of singly ionized neodymium isotopes (142, 143 and 145) at relatively small magnetic fields up to 334 G by collinear laser ion beam spectroscopy. ''Eur. Phys. J. D '''''71''', 16 (2017). https://doi.org/10.1140/epjd/e2016-70641-3</ref> Neodymium was discovered in 1885 by the Austrian chemist [[Carl Auer von Welsbach]], who also discovered [[praseodymium]]. Neodymium is present in significant quantities in the minerals [[monazite]] and [[bastnäsite]]. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Neodymium is fairly common—about as common as [[cobalt]], [[nickel]], or [[copper]]—and is [[Abundance of elements in Earth's crust|widely distributed]] in the Earth's [[Crust (geology)|crust]].<ref>See [[Abundances of the elements (data page)]].</ref> Most of the world's commercial neodymium is [[mining|mined]] in China, as is the case with many other rare-earth metals.

Neodymium [[Chemical compound|compounds]] were first commercially used as [[glass]] dyes in 1927 and remain a popular additive. The color of neodymium compounds comes from the Nd<sup>3+</sup> ion and is often a reddish-purple. This color changes with the type of lighting because of the interaction of the sharp light absorption bands of neodymium with ambient light enriched with the sharp visible emission bands of [[Mercury (element)|mercury]], trivalent [[europium]] or [[terbium]]. Glasses that have been [[Dopant|doped]] with neodymium are used in lasers that emit infrared with wavelengths between 1047 and 1062 nanometers. These lasers have been used in extremely high-power applications, such as in [[inertial confinement fusion]]. Neodymium is also used with various other [[substrate (materials science)|substrate]] crystals, such as [[yttrium aluminium garnet]] in the [[Nd:YAG laser]].

Neodymium [[alloys]] are used to make high-strength [[neodymium magnet]]s, which are powerful [[permanent magnets]].<ref>{{Cite journal |last1=Herbst |first1=J.F. |last2=Croat |first2=J.J. |date=Nov 1991 |title=Neodymium-iron-boron permanent magnets |url=https://doi.org/10.1016/0304-8853(91)90812-O |journal=Journal of Magnetism and Magnetic Materials |volume=100 |issue=1–3 |pages=57–78 |doi=10.1016/0304-8853(91)90812-o |bibcode=1991JMMM..100...57H |issn=0304-8853}}</ref> These magnets are widely used in products like microphones, professional loudspeakers, in-ear headphones, high-performance hobby DC electric motors, and computer hard disks, where low magnet mass (or volume) or strong magnetic fields are required. Larger neodymium magnets are used in [[electric motor]]s with a high [[power-to-weight ratio]] (e.g., in [[hybrid cars]]) and generators (e.g., [[aircraft]] and [[wind turbine]] [[electric generator]]s).<ref name="reu">Gorman, Steve (August 31, 2009) [https://www.reuters.com/article/newsOne/idUSTRE57U02B20090831 As hybrid cars gobble rare metals, shortage looms], ''Reuters''.</ref>

==Physical properties==

Metallic neodymium has a bright, silvery metallic luster.<ref>{{Citation |date=2009 |url=https://doi.org/10.1007/978-3-540-72816-0_15124 |work=Dictionary of Gems and Gemology |pages=598 |editor-last=Manutchehr-Danai |editor-first=Mohsen |access-date=2023-06-09 |place=Berlin, Heidelberg |publisher=Springer |language=en |doi=10.1007/978-3-540-72816-0_15124 |isbn=978-3-540-72816-0 |title=Neodymium }}</ref> Neodymium commonly exists in two [[Allotropy|allotropic]] forms, with a transformation from a double hexagonal to a [[body-centered cubic]] structure taking place at about 863&nbsp;°C.<ref name="CRC">{{cite book|chapter=Neodymium. Elements| editor= Haynes, William M. | date = 2016| title = CRC Handbook of Chemistry and Physics | edition = 97th | publisher = [[CRC Press]] | isbn = 9781498754293|page=4.23| title-link= CRC Handbook of Chemistry and Physics }}</ref> Neodymium, like most of the lanthanides, is [[paramagnetic]] at room temperature. It becomes an [[antiferromagnet]] upon cooling below {{convert|20|K|C}}.<ref>{{cite book|author1=Andrej Szytula|author2=Janusz Leciejewicz|title=Handbook of Crystal Structures and Magnetic Properties of Rare Earth Intermetallics|url=https://books.google.com/books?id=-tgM8oAQcdcC&pg=PA1|date=8 March 1994|publisher=CRC Press|isbn=978-0-8493-4261-5|page=1}}</ref> Below this transition temperature it exhibits a set of complex magnetic phases<ref>{{cite journal | last1=Zochowski | first1=S W | last2=McEwen | first2=K A | last3=Fawcett | first3=E | title=Magnetic phase diagrams of neodymium | journal=Journal of Physics: Condensed Matter | volume=3 | issue=41 | date=1991 | issn=0953-8984 | doi=10.1088/0953-8984/3/41/007 | pages=8079–8094| bibcode=1991JPCM....3.8079Z }}</ref><ref>{{cite journal | last1=Lebech | first1=B | last2=Wolny | first2=J | last3=Moon | first3=R M | title=Magnetic phase transitions in double hexagonal close packed neodymium metal-commensurate in two dimensions | journal=Journal of Physics: Condensed Matter | volume=6 | issue=27 | date=1994 | issn=0953-8984 | doi=10.1088/0953-8984/6/27/029 | pages=5201–5222| bibcode=1994JPCM....6.5201L }}</ref> that have long spin relaxation times and [[spin glass]] behavior.<ref>{{cite journal | last1=Kamber | first1=Umut | last2=Bergman | first2=Anders | last3=Eich | first3=Andreas | last4=Iuşan | first4=Diana | last5=Steinbrecher | first5=Manuel | last6=Hauptmann | first6=Nadine | last7=Nordström | first7=Lars | last8=Katsnelson | first8=Mikhail I. | last9=Wegner | first9=Daniel | last10=Eriksson | first10=Olle | last11=Khajetoorians | first11=Alexander A. | title=Self-induced spin glass state in elemental and crystalline neodymium | journal=Science | volume=368 | issue=6494 | date=2020 | issn=0036-8075 | doi=10.1126/science.aay6757 | page=| pmid=32467362 | arxiv=1907.02295 }}</ref> Neodymium is a rare-earth [[metal]] that was present in the classical [[mischmetal]] at a concentration of about 18%. To make neodymium magnets it is alloyed with [[iron]], which is a [[ferromagnet]].<ref>{{Citation |last=Stamenov |first=Plamen |title=Magnetism of the Elements |date=2021 |url=https://doi.org/10.1007/978-3-030-63210-6_15 |work=Handbook of Magnetism and Magnetic Materials |pages=659–692 |editor-last=Coey |editor-first=J. M. D. |access-date=2023-06-07 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-63210-6_15 |isbn=978-3-030-63210-6 |editor2-last=Parkin |editor2-first=Stuart S.P.}}</ref>

===Electron configuration===
Neodymium is the fourth member of the [[lanthanide]] series. In the [[periodic table]], it appears between the lanthanides [[praseodymium]] to its left and the radioactive element [[promethium]] to its right, and above the actinide [[uranium]]. Its 60 electrons are arranged in the [[Electron configuration|configuration]] [Xe]4f<sup>4</sup>6s<sup>2</sup>, of which the six 4f and 6s electrons are [[valence electron|valence]]. Like most other metals in the lanthanide series, neodymium usually only uses three electrons as valence electrons, as afterwards the remaining 4f electrons are strongly bound: this is because the 4f orbitals penetrate the most through the inert [[xenon]] core of electrons to the nucleus, followed by 5d and 6s, and this increases with higher ionic charge. Neodymium can still lose a fourth electron because it comes early in the lanthanides, where the nuclear charge is still low enough and the 4f subshell energy high enough to allow the removal of further valence electrons.{{sfn|Greenwood|Earnshaw|1997|pp=1235-8}}

==Chemical properties==
Neodymium has a melting point of {{convert|1024|C|F|abbr=on}} and a boiling point of {{convert|3074|C|F|abbr=on}}. Like other lanthanides, it usually has the [[oxidation state]] +3, but can also form in the +2 and +4 oxidation states, and even, in very rare conditions, +0.<ref name="Cloke1993" /> Neodymium metal quickly [[Redox|oxidizes]] at ambient conditions,<ref name="CRC" /> forming an oxide layer like [[iron]] rust that can [[Spallation|spall]] off and expose the metal to further oxidation; a centimeter-sized sample of neodymium corrodes completely in about a year. Nd<sup>3+</sup> is generally soluble in water. Like its neighbor [[praseodymium]], it readily burns at about 150&nbsp;°C to form [[neodymium(III) oxide]]; the oxide then peels off, exposing the bulk metal to the further oxidation:<ref name="CRC" />
:{{chem2|4Nd + 3O2 → 2Nd2O3}}

Neodymium is an electropositive element, and it reacts slowly with cold water, or quickly with hot water, to form [[neodymium(III) hydroxide]]:<ref name=webelements />
:{{chem2|2Nd (s) + 6H2O (l) → 2Nd(OH)3 (aq) + 3H2 (g)}}

Neodymium metal reacts vigorously with all the stable [[halogen]]s:<ref name=webelements>[https://www.webelements.com/neodymium/chemistry.html Neodymium: reactions of elements] {{Webarchive|url=https://web.archive.org/web/20090501190930/http://www.webelements.com/neodymium/chemistry.html |date=2009-05-01 }}. WebElements. [2017-4-10]</ref>

:{{chem2|2Nd (s) + 3F2 (g) → 2NdF3 (s)}} [a violet substance]
:{{chem2|2Nd (s) + 3Cl2 (g) → 2NdCl3 (s)}} [a mauve substance]
:{{chem2|2Nd (s) + 3Br2 (g) → 2NdBr3 (s)}} [a violet substance]
:{{chem2|2Nd (s) + 3I2 (g) → 2NdI3 (s)}} [a green substance]

Neodymium dissolves readily in dilute [[sulfuric acid]] to form solutions that contain the lilac Nd(III) [[ion]]. These exist as a [Nd(OH<sub>2</sub>)<sub>9</sub>]<sup>3+</sup> complexes:<ref>{{cite web| url =https://www.webelements.com/neodymium/chemistry.html| title =Chemical reactions of Neodymium| publisher=Webelements| access-date=2012-08-16}}</ref>

:{{chem2|2Nd (s) + 3H2SO4 (aq) → 2Nd(3+) (aq) + 3SO4(2-) (aq) + 3H2 (g)}}

===Compounds===
{{Main article|Neodymium compounds}}
: [[File:Neodym(III)sulfat.JPG|thumb|right|Neodymium(III) sulfate]][[File:Neodymium(III) acetate.jpg|thumb|right|Neodymium acetate powder]] [[File:Neodymium(III)_hydroxide.jpg|thumb|right|Neodymium(III) hydroxide powder]]
Some of the most important neodymium compounds include:
* halides: [[neodymium fluoride|NdF<sub>3</sub>]]; [[neodymium(II) chloride|NdCl<sub>2</sub>]]; [[neodymium(III) chloride|NdCl<sub>3</sub>]]; [[neodymium(III) bromide|NdBr<sub>3</sub>]]; [[neodymium(II) iodide|NdI<sub>2</sub>]]; [[neodymium(III) iodide|NdI<sub>3</sub>]]
* oxides: [[neodymium(III) oxide|{{chem2|Nd2O3}}]]
* hydroxide: [[neodymium(III) hydroxide|{{chem2|Nd(OH)3}}]]
* carbonate: [[neodymium(III) carbonate|Nd<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub>]]
* sulfate: [[neodymium(III) sulfate|{{chem2|Nd2(SO4)3}}]]
* acetate: [[neodymium acetate|Nd(CH<sub>3</sub>COO)<sub>3</sub>]]
* [[neodymium magnet]]s (Nd<sub>2</sub>Fe<sub>14</sub>B)

Some neodymium compounds vary in color under different types of lighting.<ref name="Lighting">Burke M.W. (1996) Lighting II: Sources. In: Image Acquisition. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-0069-1_2</ref>

<gallery widths="200" heights="170">
File:Neodymium tl1.jpg|Neodymium compounds in [[Fluorescent lamp|fluorescent tube]] light—from left to right, the sulfate, nitrate, and chloride
File:Neodymium fluorescent1.jpg|Neodymium compounds in [[compact fluorescent lamp]] light
File:Neodymium daylight1.jpg|Neodymium compounds in normal daylight
</gallery>

====Organoneodymium compounds====
{{See also|Organolanthanide chemistry}}
Organoneodymium compounds are compounds that have a neodymium–carbon bond. These compounds are similar to [[organolanthanide chemistry|those of the other lanthanides]], characterized by an inability to undergo [[pi backbonding|π backbonding]]. They are thus mostly restricted to the mostly ionic [[cyclopentadienide]]s (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be [[polymer]]ic.{{sfn|Greenwood|Earnshaw|1997|pp=1248-9}}

==Isotopes==
{{Infobox neodymium isotopes}}
{{Main|Isotopes of neodymium}}
Naturally occurring neodymium (<sub>60</sub>Nd) is composed of five stable [[isotope]]s—<sup>142</sup>Nd, <sup>143</sup>Nd, <sup>145</sup>Nd, <sup>146</sup>Nd and <sup>148</sup>Nd, with <sup>142</sup>Nd being the most abundant (27.2% of the [[natural abundance]])—and two [[radioisotope]]s with extremely long half-lives, <sup>144</sup>Nd ([[alpha decay]] with a [[half-life]] (''t''<sub>1/2</sub>) of {{val|2.29|e=15}} years) and <sup>150</sup>Nd ([[double beta decay]], ''t''<sub>1/2</sub>&nbsp;≈ {{val|9.3|e=18}} years). In all, 35 radioisotopes of neodymium have been detected {{as of|2022|lc=yes}}, with the most stable radioisotopes being the naturally occurring ones: <sup>144</sup>Nd and <sup>150</sup>Nd. All of the remaining [[radioactive]] isotopes have half-lives that are shorter than twelve days, and the majority of these have half-lives that are shorter than 70 seconds; the most stable [[synthetic radioisotope|artificial isotope]] is <sup>147</sup>Nd with a half-life of 10.98 days.

Neodymium also has 15 known [[metastable isotope]]s, with the most stable one being <sup>139m</sup>Nd (''t''<sub>1/2</sub>&nbsp;= 5.5 hours), <sup>135m</sup>Nd (''t''<sub>1/2</sub>&nbsp;= 5.5 minutes) and <sup>133m1</sup>Nd (''t''<sub>1/2</sub> ~70 seconds). The primary [[decay mode]]s before the most abundant stable isotope, <sup>142</sup>Nd, are [[electron capture]] and [[positron decay]], and the primary mode after is [[beta minus decay]]. The primary [[decay product]]s before <sup>142</sup>Nd are [[praseodymium]] isotopes, and the primary products after <sup>142</sup>Nd are [[promethium]] isotopes.<ref>{{cite journal | last1=Karlewski | first1=T. | last2=Hildebrand | first2=N. | last3=Herrmann | first3=G. | last4=Kaffrell | first4=N. | last5=Trautmann | first5=N. | last6=Brügger | first6=M. | title=Decay of the heaviest isotope of neodymium:154Nd | journal=Zeitschrift für Physik a Atoms and Nuclei | volume=322 | issue=1 | date=1985 | issn=0340-2193 | doi=10.1007/BF01412035 | pages=177–178}}</ref> Four of the five stable isotopes are only observationally stable, which means that they are expected to undergo radioactive decay, though with half-lives long enough to be considered stable for practical purposes.<ref name="rare decays">{{cite journal |last1=Belli |first1=P. |last2=Bernabei |first2=R. |last3=Danevich |first3=F. A. |last4=Incicchitti |first4=A. |last5=Tretyak |first5=V. I. |title=Experimental searches for rare alpha and beta decays |date=2019 |journal=[[European Physical Journal A]] |volume=55 |number=140 |pages=4–6 <!--data table--> |doi=10.1140/epja/i2019-12823-2|arxiv=1908.11458 |bibcode=2019EPJA...55..140B |s2cid=254103706 }}</ref> Additionally, some observationally stable [[isotopes of samarium]] are predicted to decay to isotopes of neodymium.<ref name="rare decays" />

Neodymium isotopes are used in various scientific applications. <sup>142</sup>Nd has been used for the production of short-lived [[isotopes of thulium]] and [[isotopes of ytterbium|ytterbium]]. <sup>146</sup>Nd has been suggested for the production of <sup>147</sup>Pm, which is a source of radioactive power. Several neodymium isotopes have been used for the production of other promethium isotopes. The decay from <sup>147</sup>Sm (''t''<sub>1/2</sub>&nbsp;= {{val|1.06|e=11|u=y}}) to the stable <sup>143</sup>Nd allows for [[samarium–neodymium dating]].<ref name=DePaolo>{{cite journal|last1=Depaolo|first1=D. J.|last2=Wasserburg|first2=G. J.|title=Nd isotopic variations and petrogenetic models|journal=Geophysical Research Letters|volume=3|pages=249|year=1976|doi=10.1029/GL003i005p00249|bibcode=1976GeoRL...3..249D|issue=5|url=https://authors.library.caltech.edu/41937/1/grl330.pdf}}</ref> <sup>150</sup>Nd has also been used to study [[double beta decay]].<ref>Barabash, A.S., Hubert, F., Hubert, P. et al. Double beta decay of <sup>150</sup>Nd to the First 0<sup>+</sup> excited state of <sup>150</sup>Sm. Jetp Lett. '''79''', 10–12 (2004). https://doi.org/10.1134/1.1675911</ref>

==History==
[[File:Auer von Welsbach.jpg|upright=0.9|thumb|[[Carl Auer von Welsbach]] (1858–1929), who discovered neodymium in 1885<ref name="Marshall">{{cite journal |last1=Marshall |first1=James L. Marshall |last2=Marshall |first2=Virginia R. Marshall |title=Rediscovery of the elements: The Rare Earths–The Last Member |journal=The Hexagon |date=2016 |pages=4–9 |url=https://chemistry.unt.edu/sites/default/files/users/owj0001/rare%20earths%20III_0.pdf |access-date=30 December 2019}}</ref>]]

In 1751, the Swedish mineralogist [[Axel Fredrik Cronstedt]] discovered a heavy mineral from the mine at [[Bastnäs]], later named [[cerite]]. Thirty years later, fifteen-year-old [[Wilhelm Hisinger]], a member of the family owning the mine, sent a sample to [[Carl Scheele]], who did not find any new elements within. In 1803, after Hisinger had become an ironmaster, he returned to the mineral with [[Jöns Jacob Berzelius]] and isolated a new oxide, which they named ''ceria'' after the [[dwarf planet]] [[Ceres (dwarf planet)|Ceres]], which had been discovered two years earlier.{{sfn|Emsley|2011|page=100}} Ceria was simultaneously and independently isolated in Germany by [[Martin Heinrich Klaproth]].{{sfn|Greenwood|Earnshaw|1997|p=1424}} Between 1839 and 1843, ceria was shown to be a mixture of oxides by the Swedish surgeon and chemist [[Carl Gustaf Mosander]], who lived in the same house as Berzelius; he separated out two other oxides, which he named ''lanthana'' and ''didymia''.<ref name="XI">{{cite journal | doi = 10.1021/ed009p1231 | last = Weeks | first = Mary Elvira |author-link=Mary Elvira Weeks| title = The Discovery of the Elements: XI. Some Elements Isolated with the Aid of Potassium and Sodium:Zirconium, Titanium, Cerium and Thorium | journal = The Journal of Chemical Education | date = 1932 | volume = 9 | issue = 7 | pages = 1231–1243 |bibcode = 1932JChEd...9.1231W }}</ref><ref name="Weeks">{{cite book |last1=Weeks |first1=Mary Elvira |title=The discovery of the elements |date=1956 |publisher=Journal of Chemical Education |location=Easton, PA |url=https://archive.org/details/discoveryoftheel002045mbp |edition=6th }}</ref><ref name="Virginia">{{cite journal |last1=Marshall |first1=James L. Marshall |last2=Marshall |first2=Virginia R. Marshall |title=Rediscovery of the elements: The Rare Earths–The Confusing Years |journal=The Hexagon |date=2015 |pages=72–77 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20II.pdf |access-date=30 December 2019}}</ref> He partially decomposed a sample of [[cerium nitrate]] by roasting it in air and then treating the resulting oxide with dilute [[nitric acid]]. The metals that formed these oxides were thus named ''lanthanum'' and ''[[didymium]]''.<ref>See:
* {{Cite book |author=Académie des sciences (France) |url=http://archive.org/details/ComptesRendusAcademieDesSciences0008 |title=Comptes rendus Academie des sciences 0008 |date=1839  |language=fr}} From p. 356: ''"L'oxide de cérium, extrait de la cérite par la procédé ordinaire, contient à peu près les deux cinquièmes de son poids de l'oxide du nouveau métal qui ne change que peu les propriétés du cérium, et qui s'y tient pour ainsi dire caché. Cette raison a engagé M. Mosander à donner au nouveau métal le nom de ''Lantane''."'' (The oxide of cerium, extracted from cerite by the usual procedure, contains almost two fifths of its weight in the oxide of the new metal, which differs only slightly from the properties of cerium, and which is held in it so to speak "hidden". This reason motivated Mr. Mosander to give to the new metal the name ''Lantane'').
* {{Cite book |url=https://books.google.com/books?id=dF1KiX7MbSMC&pg=PA390 |title=Philosophical Magazine |date=1839 |publisher=Taylor & Francis |language=en}}</ref> Didymium was later proven to not be a single element when it was split into two elements, praseodymium and neodymium, by [[Carl Auer von Welsbach]] in [[Vienna]] in 1885.<ref>{{cite journal |last1=v. Welsbach |first1=Carl Auer |title=Die Zerlegung des Didyms in seine Elemente |journal=Monatshefte für Chemie und verwandte Teile anderer Wissenschaften |volume=6|issue=1 |year=1885|pages=477–491 |doi=10.1007/BF01554643|s2cid=95838770 }}</ref><ref>{{Cite book|title = Extractive Metallurgy of Rare Earths|last1 = Krishnamurthy|first1 = N.|publisher = CRC Press|year = 2004|isbn = 978-0-203-41302-9|pages = 6|last2 = Gupta|first2 = C. K.}}</ref><!-- The year of discovery is wrong in this book. Confirmed by an email from the author--> Von Welsbach confirmed the separation by [[spectroscopic]] analysis, but the products were of relatively low purity. Pure neodymium was first isolated in 1925. The name neodymium is derived from the Greek words ''neos'' (νέος), new, and ''didymos'' (διδύμος), twin.<ref name="CRC" /><ref name="history">{{cite book|url=https://archive.org/details/naturesbuildingb0000emsl|url-access=registration| pages= [https://archive.org/details/naturesbuildingb0000emsl/page/268 268]–270|title = Nature's building blocks: an A–Z guide to the elements| author =Emsley, John | publisher= Oxford University Press| date = 2003| isbn = 0-19-850340-7}}</ref><ref name="XVI">{{cite journal|last1=Weeks|first1=Mary Elvira|title=The discovery of the elements. XVI. The rare earth elements|journal=Journal of Chemical Education|volume=9|issue=10|year=1932|pages=1751|doi=10.1021/ed009p1751|bibcode=1932JChEd...9.1751W}}</ref>

Double nitrate crystallization was the means of commercial neodymium purification until the 1950s. Lindsay Chemical Division was the first to commercialize large-scale ion-exchange purification of neodymium. Starting in the 1950s, high purity (>99%) neodymium was primarily obtained through an [[ion exchange]] process from [[monazite]], a mineral rich in rare-earth elements.<ref name="CRC" /> The metal is obtained through [[electrolysis]] of its [[halide]] [[Salt (chemistry)|salts]]. Currently, most neodymium is extracted from [[bastnäsite]] and purified by solvent extraction. Ion-exchange purification is used for the highest purities (typically >99.99%). Since then, the glass technology has improved due to the improved purity of commercially available neodymium oxide and the advancement of glass technology in general. Early methods of separating the lanthanides depended on fractional crystallization, which did not allow for the isolation of high-purity neodymium until the aforementioned ion exchange methods were developed after World War II.<ref>{{Citation |last=Cotton |first=Simon A. |title=The Rare Earths, a Challenge to Mendeleev, No Less Today |date=2021 |url=https://doi.org/10.1007/978-3-030-67910-1_11 |work=150 Years of the Periodic Table: A Commemorative Symposium |pages=259–301 |editor-last=Giunta |editor-first=Carmen J. |access-date=2023-06-07 |series=Perspectives on the History of Chemistry |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-67910-1_11 |isbn=978-3-030-67910-1 |s2cid=238942033 |editor2-last=Mainz |editor2-first=Vera V. |editor3-last=Girolami |editor3-first=Gregory S.}}</ref>

==Occurrence and production==
===Occurrence===
[[File:Bastnaesite - Kischtimsk, Ural.jpg|thumb|left|[[Bastnäsite]]]]
Neodymium is rarely found in nature as a free element, instead occurring in ores such as [[monazite]] and [[bastnäsite]] (which are [[mineral group]]s rather than single minerals) that contain small amounts of all rare-earth elements. Neodymium is rarely dominant in these minerals, with exceptions such as monazite-(Nd) and kozoite-(Nd).<ref>
{{cite web |url=https://www.mindat.org/ |title=Mindat.org |author=Hudson Institute of Mineralogy |date=1993–2018 }}</ref> The main mining areas are in China, United States, Brazil, India, Sri Lanka, and Australia.

The Nd<sup>3+</sup> ion is similar in size to ions of the early lanthanides of the [[cerium group]] (those from lanthanum to [[samarium]] and [[europium]]). As a result, it tends to occur along with them in [[phosphate]], [[silicate]] and [[carbonate]] minerals, such as [[monazite]] (M<sup>III</sup>PO<sub>4</sub>) and [[bastnäsite]] (M<sup>III</sup>CO<sub>3</sub>F), where M refers to all the rare-earth metals except scandium and the radioactive [[promethium]] (mostly Ce, La, and Y, with somewhat less Pr and Nd).{{sfn|Greenwood|Earnshaw|1997|pp=1229-32}} Bastnäsite is usually lacking in [[thorium]] and the heavy lanthanides, and the purification of the light lanthanides from it is less involved than from monazite. The ore, after being crushed and ground, is first treated with hot concentrated sulfuric acid, which liberates carbon dioxide, [[hydrogen fluoride]], and [[silicon tetrafluoride]]. The product is then dried and leached with water, leaving the early lanthanide ions, including lanthanum, in solution.{{sfn|Greenwood|Earnshaw|1997|pp=1229-32}}{{Failed verification|date=May 2024|reason=Source discusses treatment of both ores with HCl etc to produce LnCl3 but not treatment with sulfuric acid.}}

{| class="wikitable" style="float:right; margin-right:15px; margin-down:0; font-size:10pt; line-height:11pt;"
|+ style="margin-bottom: 5px;" | Solar System abundances{{sfn|Lodders|2003|pp=1222–1223}}
! style="text-align:center;" | Atomic<br />number
! style="width:45%;"| Element
! style="padding-right: 5px; padding-left: 10px;" | Relative<br />amount
|-
| style="text-align:center;" | 42
| style="text-align:center;"| [[Molybdenum]]
| style="padding-right:5px; text-align:right;"|2.771
|-
| style="text-align:center;" | 47
| style="text-align:center;"| [[Silver]]
| style="padding-right:5px; text-align:right;"|0.590
|-
| style="text-align:center;"| 50
| style="text-align:center; "| [[Tin]]
| style="padding-right:5px; text-align:right;"|4.699
|-
| style="text-align:center;" | 58
| style="text-align:center;"| [[Cerium]]
| style="padding-right:5px; text-align:right;"|1.205
|-
| style="text-align:center;" | 59
| style="text-align:center;"| [[Praseodymium]]
| style="padding-right:5px; text-align:right;"|0.205
|- style="background:#ff9;"
| style="text-align:center;" | ''60''
| style="text-align:center;"| ''Neodymium''
| style="padding-right:5px; text-align:right;"|''1''
|-
| style="text-align:center;" | 74
| style="text-align:center;"| [[Tungsten]]
| style="padding-right:5px; text-align:right;"|0.054
|-
| style="text-align:center;" | 90
| style="text-align:center;"| [[Thorium]]
| style="padding-right:5px; text-align:right;"| 0.054
|-
| style="text-align:center;" | 92
| style="text-align:center;"| [[Uranium]]
| style="padding-right:5px; text-align:right;"| 0.022
|}

====In space====
Neodymium's per-particle abundance in the [[Solar System]] is 0.083 [[parts per billion|ppb]] (parts per billion).{{sfn|Lodders|2003|pp=1222–1223}}{{efn|Abundances in the source are listed relative to silicon rather than in per-particle notation. The sum of all elements per 10<sup>6</sup> parts of silicon is 2.6682{{e|10}} parts; lead comprises 3.258 parts.}} This figure is about two thirds of that of [[platinum]], but two and a half times more than mercury, and nearly five times more than gold.{{sfn|Lodders|2003|pp=1222–1223}} The lanthanides are not usually found in space, and are much more abundant in the [[Abundance of elements in Earth's crust|Earth's crust]].{{sfn|Lodders|2003|pp=1222–1223}}<ref name="CRC abundance">A{{lc:BUNDANCE OF ELEMENTS IN THE EARTH’S CRUST AND IN THE SEA}}, ''CRC Handbook of Chemistry and Physics,'' 97th edition (2016–2017), p. 14-17</ref>

====In the Earth's crust====
[[File:Elemental abundances.svg|thumb|right|upright=1.25|Neodymium is a fairly common element in the [[Earth's crust]] for being a rare-earth metal. Most rare-earth metals are less abundant.|alt=A line chart generally declining towards its right]]
Neodymium is classified as a [[Goldschmidt classification#Lithophile elements|lithophile]] under the [[Goldschmidt classification]], meaning that it is generally found combined with oxygen. Although it belongs to the rare-earth metals, neodymium is not rare at all. Its [[Abundance of elements in Earth's crust|abundance in the Earth's crust]] is about 41&nbsp;mg/kg.<ref name="CRC abundance"/> It is similar in abundance to [[lanthanum]].

===Production===
The world's production of neodymium was about 7,000 tons in 2004.<ref name="history" /> The bulk of current production is from China. Historically, the Chinese government imposed strategic material controls on the element, causing large fluctuations in prices.<ref>{{Cite web |title=Rare Earths Statistics and Information {{!}} U.S. Geological Survey |url=http://minerals.usgs.gov/minerals/pubs/commodity/rare_earths/mcs-2016-raree.pdf |archive-url=https://web.archive.org/web/20160506184123/http://minerals.usgs.gov/minerals/pubs/commodity/rare_earths/mcs-2016-raree.pdf |archive-date=2016-05-06 |url-status=dead |access-date=2023-06-07 |website=minerals.usgs.gov |language=en}}</ref> The uncertainty of pricing and availability have caused companies (particularly Japanese ones) to create permanent magnets and associated electric motors with fewer rare-earth metals; however, so far they have been unable to eliminate the need for neodymium.<ref>{{cite news|url=https://www.reuters.com/article/honda-rareearths-idUST9N18R02G|title=Honda co-develops first hybrid car motor free of heavy rare earth metals|date=12 July 2016|work=Reuters}}</ref><ref>{{cite news|url=https://www.bloomberg.com/news/articles/2016-07-12/honda-readies-heavy-rare-earth-free-hybrids-to-sidestep-china|title=Honda's Heavy Rare Earth-Free Hybrid Motors Sidestep China|date=12 July 2016|newspaper=Bloomberg.com}}</ref> According to the [[US Geological Survey]], [[Greenland]] holds the largest reserves of undeveloped rare-earth deposits, particularly neodymium. [[Mining industry|Mining interests]] clash with native populations at those sites, due to the release of radioactive substances, mainly [[thorium]], during the mining process.<ref>{{Cite news |date=2021-03-31 |title=Greenland to hold election watched closely by global mining industry |language=en |work=Reuters |url=https://www.reuters.com/article/us-greenland-election-idUSKBN2BN1U6 |access-date=2023-06-07}}</ref>
[[File:Monazite acid cracking process.svg|frameless|center|730px]]

Neodymium is typically 10–18% of the rare-earth content of commercial deposits of the light rare-earth-element minerals bastnäsite and monazite.<ref name="CRC" /> With neodymium compounds being the most strongly colored for the trivalent lanthanides, it can occasionally dominate the coloration of rare-earth minerals when competing chromophores are absent. It usually gives a pink coloration. Outstanding examples of this include monazite crystals from the [[tin]] deposits in [[Llallagua]], Bolivia; [[ancylite]] from [[Mont Saint-Hilaire]], [[Quebec]], Canada; or lanthanite from [[Lower Saucon Township, Pennsylvania]]. As with neodymium glasses, such minerals change their colors under the differing lighting conditions. The absorption bands of neodymium interact with the visible [[emission spectrum]] of [[Mercury-vapor lamp|mercury vapor]], with the unfiltered shortwave UV light causing neodymium-containing minerals to reflect a distinctive green color. This can be observed with monazite-containing sands or bastnäsite-containing ore.<ref>{{Cite journal |last1=Buzhinskii |first1=I. M. |last2=Mamonov |first2=S. K. |last3=Mikhailova |first3=L. I. |date=1971-08-01 |title=Influence of specific neodymium-glass absorption bands on generating energy |url=https://doi.org/10.1007/BF00607297 |journal=Journal of Applied Spectroscopy |language=en |volume=15 |issue=2 |pages=1002–1005 |doi=10.1007/BF00607297 |bibcode=1971JApSp..15.1002B |s2cid=95996476 |issn=1573-8647}}</ref>

The demand for mineral resources, such as [[rare earth metals|rare-earth elements]] (including neodymium) and other critical materials, has been rapidly increasing owing to the growing human [[population]] and industrial development. Recently, the requirement for a low-carbon society has led to a significant demand for energy-saving technologies such as batteries, high-efficiency motors, renewable energy sources, and fuel cells. Among these technologies, permanent magnets are often used to fabricate high-efficiency motors, with neodymium-iron-boron magnets (Nd<sub>2</sub>Fe<sub>14</sub>B sintered and bonded magnets; hereinafter referred to as [[Neodymium magnet|NdFeB magnets]]) being the main type of permanent magnet in the market since their invention.<ref>Sagawa M, Fujimura S, Togawa N, Yamamoto H, Matsuura Y (1984) New material for permanent magnets on a base of Nd and Fe. J Appl Phys 55(6):2083–2087. https://doi.org/10.1063/1.333572</ref> NdFeB magnets are used in [[hybrid electric vehicles]], [[plug-in hybrid|plug-in hybrid electric vehicles]], [[electric vehicle]]s, [[fuel cell vehicle]]s, [[wind turbine]]s, [[home appliance]]s, computers, and many small consumer electronic devices.<ref name="Yang Yongxiang">{{Cite journal |last1=Yang |first1=Yongxiang |last2=Walton |first2=Allan |last3=Sheridan |first3=Richard |last4=Güth |first4=Konrad |last5=Gauß |first5=Roland |last6=Gutfleisch |first6=Oliver |last7=Buchert |first7=Matthias |last8=Steenari |first8=Britt-Marie |last9=Van Gerven |first9=Tom |last10=Jones |first10=Peter Tom |last11=Binnemans |first11=Koen |date=2017-03-01 |title=REE Recovery from End-of-Life NdFeB Permanent Magnet Scrap: A Critical Review |journal=Journal of Sustainable Metallurgy |language=en |volume=3 |issue=1 |pages=122–149 |doi=10.1007/s40831-016-0090-4 |issn=2199-3831|doi-access=free |bibcode=2017JSusM...3..122Y }}</ref> Furthermore, they are indispensable for energy savings. Toward achieving the objectives of the [[Paris Agreement]], the demand for NdFeB magnets is expected to increase significantly in the future.<ref name="Yang Yongxiang" />

==Applications==

===Magnets===
{{Further|Neodymium magnet}}
[[File:Neodymag.jpg|thumb|Neodymium magnet on a [[mu-metal]] bracket from a [[hard drive]]]]
[[Neodymium magnet]]s (an alloy, Nd<sub>2</sub>Fe<sub>14</sub>B) are the strongest [[permanent magnet]]s known. A neodymium magnet of a few tens of grams can lift a thousand times its own weight, and can snap together with enough force to break bones. These magnets are cheaper, lighter, and stronger than [[samarium–cobalt magnet]]s. However, they are not superior in every aspect, as neodymium-based magnets lose their magnetism at lower temperatures<ref>Zhang, W., Liu, G. & Han, K. The Fe-Nd (Iron-Neodymium) system. JPE 13, 645–648 (1992). https://doi.org/10.1007/BF02667216</ref> and tend to corrode,<ref>{{Cite journal |last1=Bala |first1=H. |last2=Szymura |first2=S. |last3=Pawłowska |first3=G. |last4=Rabinovich |first4=Yu. M. |date=1993-10-01 |title=Effect of impurities on the corrosion behaviour of neodymium |url=https://doi.org/10.1007/BF00266123 |journal=Journal of Applied Electrochemistry |language=en |volume=23 |issue=10 |pages=1017–1024 |doi=10.1007/BF00266123 |s2cid=95479959 |issn=1572-8838}}</ref> while samarium–cobalt magnets do not.<ref>{{Cite journal |last1=Hopp |first1=M. |last2=Rogaschewski |first2=S. |last3=Groth |first3=Th. |date=2003-04-01 |title=Testing the cytotoxicity of metal alloys used as magnetic prosthetic devices |url=https://doi.org/10.1023/A:1022931915709 |journal=Journal of Materials Science: Materials in Medicine |language=en |volume=14 |issue=4 |pages=335–345 |doi=10.1023/A:1022931915709 |pmid=15348458 |s2cid=36896100 |issn=1573-4838}}</ref>

Neodymium magnets appear in products such as [[microphone]]s, professional [[loudspeaker]]s, [[headphones]], [[guitar]] and [[bass guitar]] [[Pickup (music technology)|pick-ups]], and computer [[hard disk]]s where low mass, small volume, or strong magnetic fields are required. Neodymium is used in the electric motors of hybrid and electric automobiles<ref name="Yang Yongxiang"/> and in the electricity generators of some designs of commercial wind turbines (only wind turbines with "permanent magnet" generators use neodymium).<ref>{{cite web |url=https://www.stanfordmagnets.com/application-of-neodymium-magnets-in-wind-turbine-generators.html |title=Application of Neodymium Magnets in Wind Turbine Generators |last=Marchio |first=Cathy |date=Apr 16, 2024 |website=Stanford Magnets |access-date=Aug 16, 2024}}</ref> For example, drive electric motors of each [[Toyota Prius]] require {{convert|1|kg|lb|abbr=off|spell=in}} of neodymium per vehicle.{{r|reu}} Neodymium magnets are also widely used in pure electric vehicle motors, driving rapid growth in demand. <ref>{{Cite journal |last1=Pozo-Gonzalo |first1=Cristina |last2=Golmohammadzadeh |first2=Rabeeh |last3=Myekhlai |first3=Munkhshur |last4=Bastos |first4=Henrique |last5=Deacon |first5=Glen B. |last6=Somers |first6=Anthony E. |date=2024-03-04 |title=Selective neodymium recovery from model permanent magnets using cost-effective organic acid systems |url=https://pubs.rsc.org/en/content/articlelanding/2024/gc/d3gc04800d |journal=Green Chemistry |language=en |volume=26 |issue=5 |pages=2740–2749 |doi=10.1039/D3GC04800D |issn=1463-9270}}</ref> Neodymium magnets are used in medical devices such as MRI and treatments for chronic pain and wound healing. <ref>{{Cite journal |last1=Yuksel |first1=Cengiz |last2=Ankarali |first2=Seyit |last3=Yuksel |first3=Nehir Aslan |date=September 2018 |title=The use of neodymium magnets in healthcare and their effects on health |journal=Northern Clinics of Istanbul |volume=5 |issue=3 |pages=268–273 |doi=10.14744/nci.2017.00483 |issn=2536-4553 |pmc=6323575 |pmid=30688942}}</ref>

===Glass===
[[File:Neodymium glass light bulb under fluorescent and incandescent light.jpg|thumb|left|A neodymium glass [[light bulb]], with the base and inner coating removed, under two different types of light: [[fluorescent]] on the left, and [[incandescent]] on the right.]]
[[File:ACE Didymium Glasses RX-1205-BK Z87+.JPG|thumb|left|Didymium glasses]]
Neodymium glass (Nd:glass) is produced by the inclusion of [[neodymium(III) oxide|neodymium oxide]] (Nd<sub>2</sub>O<sub>3</sub>) in the glass melt. In daylight or [[Incandescent light bulb|incandescent]] light neodymium glass appears lavender, but it appears pale blue under [[Fluorescent lamp|fluorescent]] lighting. Neodymium may be used to color glass in shades ranging from pure violet through wine-red and warm gray.<ref>{{Cite journal |last1=Kondrukevich |first1=A. A. |last2=Vlasov |first2=A. S. |last3=Platov |first3=Yu. T. |last4=Rusovich-Yugai |first4=N. S. |last5=Gorbatov |first5=E. P. |date=2008-05-01 |title=Color of porcelain containing neodymium oxide |url=https://doi.org/10.1007/s10717-008-9039-9 |journal=Glass and Ceramics |language=en |volume=65 |issue=5 |pages=203–207 |doi=10.1007/s10717-008-9039-9 |s2cid=137474301 |issn=1573-8515}}</ref>

The first commercial use of purified neodymium was in glass coloration, starting with experiments by Leo Moser in November 1927. The resulting "Alexandrite" glass remains a signature color of the Moser glassworks to this day. Neodymium glass was widely emulated in the early 1930s by American glasshouses, most notably Heisey, Fostoria ("wisteria"), Cambridge ("heatherbloom"), and Steuben ("wisteria"), and elsewhere (e.g. Lalique, in France, or Murano). Tiffin's "twilight" remained in production from about 1950 to 1980.<ref>{{cite web|url=http://coloradosprings.yourhub.com/CrippleCreekTellerCounty/Stories/Arts/Story~443258.aspx|archive-url=https://web.archive.org/web/20080403165916/http://coloradosprings.yourhub.com/CrippleCreekTellerCounty/Stories/Arts/Story~443258.aspx |archive-date=2008-04-03|title =Chameleon Glass Changes Color|access-date=2009-06-06}}</ref> Current sources include glassmakers in the Czech Republic, the United States, and China.<ref>Brown D.C. (1981) Optical-Pump Sources for Nd : Glass Lasers. In: High-Peak-Power Nd: Glass Laser Systems. Springer Series in Optical Sciences, vol 25. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-38508-0_3</ref>

The sharp absorption bands of neodymium cause the glass color to change under different lighting conditions, being reddish-purple under [[daylight]] or yellow [[incandescent light]], blue under white [[fluorescent light]]ing, and greenish under [[Trichromacy|trichromatic]] lighting. In combination with [[gold]] or [[selenium]], red colors are produced. Since neodymium coloration depends upon "[[Forbidden mechanism|forbidden]]" f-f transitions deep within the atom, there is relatively little influence on the color from the chemical environment, so the color is impervious to the thermal history of the glass. However, for the best color, iron-containing impurities need to be minimized in the [[silica]] used to make the glass. The same forbidden nature of the f-f transitions makes rare-earth colorants less intense than those provided by most d-transition elements, so more has to be used in a glass to achieve the desired color intensity. The original Moser recipe used about 5% of neodymium oxide in the glass melt, a sufficient quantity such that Moser referred to these as being "rare-earth doped" glasses. Being a strong base, that level of neodymium would have affected the melting properties of the glass, and the [[Calcium oxide|lime]] content of the glass might have needed adjustments.<ref>{{cite book|page=[https://archive.org/details/dictionaryofglas0000bray/page/102 102]|url=https://archive.org/details/dictionaryofglas0000bray|url-access=registration| title=Dictionary of glass: materials and techniques| author=Bray, Charles | publisher= University of Pennsylvania Press| date = 2001| isbn=0-8122-3619-X}}</ref>

Light transmitted through neodymium glasses shows unusually sharp [[absorption band]]s; the glass is used in [[astronomy|astronomical work]] to produce sharp bands by which [[spectral line]]s may be calibrated.<ref name="CRC" /> Another application is the creation of selective astronomical filters to reduce the effect of light pollution from sodium and fluorescent lighting while passing other colours, especially dark red hydrogen-alpha emission from nebulae.<ref>[https://www.firstlightoptics.com/light-pollution-reduction/baader-neodymium-filter.html Baader Neodymium Filter], First Light Optics.</ref> Neodymium is also used to remove the green color caused by iron contaminants from glass.<ref>{{Cite journal |last1=Peelman |first1=S. |last2=Sietsma |first2=J. |last3=Yang |first3=Y. |date=2018-06-01 |title=Recovery of Neodymium as (Na, Nd)(SO4)2 from the Ferrous Fraction of a General WEEE Shredder Stream |journal=Journal of Sustainable Metallurgy |language=en |volume=4 |issue=2 |pages=276–287 |doi=10.1007/s40831-018-0165-5 |issn=2199-3831|doi-access=free |bibcode=2018JSusM...4..276P }}</ref>

[[File:Yag-rod.jpg|thumb|right|Nd:YAG laser rod]]
Neodymium is a component of "[[didymium]]" (referring to mixture of salts of neodymium and [[praseodymium]]) used for coloring glass to make welder's and glass-blower's goggles; the sharp absorption bands obliterate the strong sodium emission at 589&nbsp;nm. The similar absorption of the yellow mercury emission line at 578&nbsp;nm is the principal cause of the blue color observed for neodymium glass under traditional white-fluorescent lighting. Neodymium and didymium glass are used in color-enhancing filters in indoor photography, particularly in filtering out the yellow hues from incandescent lighting. Similarly, neodymium glass is becoming widely used more directly in [[incandescent light bulb]]s. These lamps contain neodymium in the glass to filter out yellow light, resulting in a whiter light which is more like sunlight.<ref>{{cite journal |last1=Zhang |first1=Liqiang |last2=Lin |first2=Hang |last3=Cheng |first3=Yao |last4=Xu |first4=Ju |last5=Xiang |first5=Xiaoqiang |last6=Wang |first6=Congyong |last7=Lin |first7=Shisheng |last8=Wang |first8=Yuansheng |title=Color-filtered phosphor-in-glass for LED-lit LCD with wide color gamut |journal=Ceramics International |date=August 2019 |volume=45 |issue=11 |pages=14432–14438 |doi=10.1016/j.ceramint.2019.04.164|s2cid=149699364 }}</ref> During [[World War I]], didymium mirrors were reportedly used to transmit [[Morse code]] across battlefields.<ref name=b1>{{cite book |author1=Fontani, Marco |author2=Costa, Mariagrazia |author3=Orna, Mary Virginia |title=The Lost Elements: The Periodic Table's Shadow Side |url=https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA173 |year=2015 |publisher=Oxford University Press |isbn=978-0-19-938334-4 |pages=172–173}}</ref> Similar to its use in glasses, neodymium salts are used as a colorant for [[vitreous enamel|enamels]].<ref name="CRC" />

===Lasers===
Certain transparent materials with a small concentration of neodymium ions can be used in lasers as [[gain medium|gain media]] for infrared wavelengths (1054–1064&nbsp;nm), e.g. [[Nd:YAG laser|Nd:YAG]] (yttrium aluminium garnet), Nd:YAP (yttrium aluminium [[perovskite]]),<ref>{{cite book |last1=Sulc |first1=Jan |last2=Jelinkova |first2=Helena |last3=Jabczynski |first3=Jan K. |last4=Zendzian |first4=Waldemar |last5=Kwiatkowski |first5=Jacek |last6=Nejezchleb |first6=Karel |last7=Skoda |first7=Vaclav |editor1-first=Hanna J |editor1-last=Hoffman |editor2-first=Ramesh K |editor2-last=Shori |title=Solid State Lasers XIV: Technology and Devices |chapter=Comparison of diode-side-pumped triangular Nd:YAG and Nd:YAP laser |date=27 April 2005 |volume=5707 |pages=325 |doi=10.1117/12.588233 |s2cid=121802212 |chapter-url=https://www.crytur.cz/storage/cryt_UK-General/posters%20laser/Nd_triangl.pdf |access-date=16 February 2022}}</ref> [[Neodymium-doped yttrium lithium fluoride|Nd:YLF]] (yttrium lithium fluoride), [[Neodymium-doped yttrium orthovanadate|Nd:YVO<sub>4</sub>]] (yttrium orthovanadate), and Nd:glass. Neodymium-doped crystals (typically Nd:YVO<sub>4</sub>) generate high-powered infrared laser beams which are converted to green laser light in commercial [[DPSS]] hand-held lasers and [[laser pointer]]s.<ref>{{Cite web |last=Tanjib Atique Khan |date=2012-06-27 |title=Solid State Laser & Semiconductor Laser |url=http://dewan.buet.ac.bd/EEE6503/Reports/Report_Chap12-13_SolidStateLasers+SemiconductorLasers.pdf}}</ref> 

[[File:Laser glass slabs.jpg|thumb|right|upright=1.4|Neodymium doped glass slabs used in extremely powerful lasers for [[inertial confinement fusion]]]]

Trivalent neodymium ion Nd<sup>3+</sup> was the first lanthanide from rare-earth elements used for the generation of laser radiation. The Nd:CaWO<sub>4</sub> laser was developed in 1961.<ref>{{cite journal|doi=10.1103/PhysRev.126.1406|title=Continuous operation of a solid-state optical maser|year=1962|last1=Johnson|first1=L. F.|last2=Boyd|first2=G. D.|last3=Nassau|first3=K.|last4=Soden|first4=R. R.|journal=Physical Review|volume=126|issue=4|page=1406|bibcode=1962PhRv..126.1406J }}</ref> Historically, it was the third laser which was put into operation (the first was ruby, the second the U<sup>3+</sup>:CaF laser). Over the years the neodymium laser became one of the most used lasers for application purposes. The success of the Nd<sup>3+</sup> ion lies in the structure of its energy levels and in the spectroscopic properties suitable for the generation of laser radiation. In 1964 Geusic et al.<ref>{{cite journal|doi=10.1063/1.1753928|title=Laser oscillations in nd-doped yttrium aluminum, yttrium gallium and gadolinium garnets|year=1964|last1=Geusic|first1=J. E.|last2=Marcos|first2=H. M.|last3=Van Uitert|first3=L. G.|journal=Applied Physics Letters|volume=4|issue=10|page=182|bibcode = 1964ApPhL...4..182G }}</ref> demonstrated the operation of neodymium ion in YAG matrix Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>. It is a four-level laser with lower threshold and with excellent mechanical and temperature properties. For optical pumping of this material it is possible to use non-coherent flashlamp radiation or a coherent diode beam.<ref>Koechner, 1999; Powell, 1998; Svelto, 1998; Siegman, 1986</ref>

[[File:YAG2.svg|thumb|right|upright=1.4|Neodymium ions in various types of ionic crystals, and also in glasses, act as a laser gain medium, typically emitting 1064 nm light from a particular atomic transition in the neodymium ion, after being "pumped" into excitation from an external source.]]
The current laser at the UK [[Atomic Weapons Establishment]] (AWE), the HELEN (High Energy Laser Embodying Neodymium) 1-[[terawatt]] neodymium-glass laser, can access the midpoints of pressure and temperature regions and is used to acquire data for modeling on how density, temperature, and pressure interact inside warheads. HELEN can create plasmas of around 10<sup>6</sup> [[Kelvin|K]], from which opacity and transmission of radiation are measured.<ref>{{cite journal|doi=10.1364/AO.41.003497|title=Multipass Reconfiguration of the HELEN Nd:Glass Laser at the Atomic Weapons Establishment|date=2002|journal=Applied Optics|volume=41|pages=3497–505|pmid=12078672|issue=18|bibcode = 2002ApOpt..41.3497N |display-authors=4 |last2=Andrew|first2=J. E.|last3=Bett|first3=T. H.|last4=Clifford|first4=R. K.|last5=England|first5=J. E.|last6=Hopps|first6=N. W.|last7=Parker|first7=K. W.|last8=Porter|last9=Stevenson|last1=Norman|first1=M. J.}}</ref>

Neodymium glass [[solid-state laser]]s are used in extremely high power ([[1 E11 W#1 terawatt|terawatt]] scale), high energy ([[megajoule]]s) multiple beam systems for [[inertial confinement fusion]]. Nd:glass lasers are usually [[nonlinear optics|frequency tripled]] to the [[optical frequency multiplier|third harmonic]] at 351&nbsp;nm in laser fusion devices.<ref>{{Cite journal |last1=Wang |first1=W. |last2=Wang |first2=J. |last3=Wang |first3=F. |last4=Feng |first4=B. |last5=Li |first5=K. |last6=Jia |first6=H. |last7=Han |first7=W. |last8=Xiang |first8=Y. |last9=Li |first9=F. |last10=Wang |first10=L. |last11=Zhong |first11=W. |last12=Zhang |first12=X. |last13=Zhao |first13=S. |date=2010-10-01 |title=Third harmonic generation of Nd:glass laser with novel composite deuterated KDP crystals |url=https://doi.org/10.1134/S1054660X10190175 |journal=Laser Physics |language=en |volume=20 |issue=10 |pages=1923–1926 |doi=10.1134/S1054660X10190175 |bibcode=2010LaPhy..20.1923W |s2cid=123703318 |issn=1555-6611}}</ref>

===Other===
Other applications of neodymium include:
* Neodymium has an unusually large [[specific heat capacity]] at liquid-helium temperatures, so is useful in [[cryocoolers]].<ref>{{Citation |last1=Osborne |first1=M. G. |title=Centrifugal Atomization of Neodymium and Er3Ni Regenerator Particulate |date=1994 |url=https://doi.org/10.1007/978-1-4757-9053-5_80 |work=Advances in Cryogenic Engineering Materials: Volume 40, Part A |pages=631–638 |editor-last=Reed |editor-first=Richard P. |access-date=2023-06-07 |series=An International Cryogenic Materials Conference Publication |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-1-4757-9053-5_80 |isbn=978-1-4757-9053-5 |last2=Anderson |first2=I. E. |last3=Gschneidner |first3=K. A. |last4=Gailloux |first4=M. J. |last5=Ellis |first5=T. W. |editor2-last=Fickett |editor2-first=Fred R. |editor3-last=Summers |editor3-first=Leonard T. |editor4-last=Stieg |editor4-first=M.}}</ref><ref>{{Cite web |title=Neodymium: Properties and Applications |url=https://www.stanfordmaterials.com/blog/neodymium-properties-and-applications.html |access-date=2025-05-13 |website=www.stanfordmaterials.com |language=en}}</ref>
* [[Neodymium acetate]] can be used as a standard contrasting agent in [[Electron microscope|electron microscopy]] (a substitute for the radioactive and toxic [[uranyl acetate]]).<ref name="uranyl acetate">{{Cite journal |last1=Kuipers |first1=Jeroen |last2=Giepmans |first2=Ben N. G. |date=2020-04-01 |title=Neodymium as an alternative contrast for uranium in electron microscopy |url=https://doi.org/10.1007/s00418-020-01846-0 |journal=Histochemistry and Cell Biology |language=en |volume=153 |issue=4 |pages=271–277 |doi=10.1007/s00418-020-01846-0 |issn=1432-119X |pmc=7160090 |pmid=32008069}}</ref>
* Probably because of similarities to Ca<sup>2+</sup>, Nd<sup>3+</sup> has been reported<ref>{{cite journal|author=Wei, Y. and Zhou, X.|title=The Effect of Neodymium (Nd<sup>3+</sup>) on Some Physiological Activities in Oilseed Rape during Calcium (Ca<sup>2+</sup>) Starvation|url=http://www.regional.org.au/au/gcirc/2/399.htm |journal=10th International Rapeseed Congress|volume=2|page=399|year=1999}}</ref> to promote plant growth. Rare-earth element compounds are frequently used in China as [[fertilizer]].<ref>{{Cite journal |last1=Tommasi |first1=Franca |last2=Thomas |first2=Philippe J. |last3=Pagano |first3=Giovanni |last4=Perono |first4=Genevieve A. |last5=Oral |first5=Rahime |last6=Lyons |first6=Daniel M. |last7=Toscanesi |first7=Maria |last8=Trifuoggi |first8=Marco |date=2021-11-01 |title=Review of Rare Earth Elements as Fertilizers and Feed Additives: A Knowledge Gap Analysis |url=https://doi.org/10.1007/s00244-020-00773-4 |journal=Archives of Environmental Contamination and Toxicology |language=en |volume=81 |issue=4 |pages=531–540 |doi=10.1007/s00244-020-00773-4 |issn=1432-0703 |pmc=8558174 |pmid=33141264|bibcode=2021ArECT..81..531T }}</ref>
* [[Samarium–neodymium dating]] is useful for determining the age relationships of rocks<ref>{{cite news| url=http://news.bbc.co.uk/2/hi/science/nature/7639024.stm|title =Team finds Earth's 'oldest rocks'|work =BBC News|access-date = 2009-06-06|date=2008-09-26|location=London}}</ref> and meteorites.<ref>{{Citation |last=Carlson |first=Richard W. |title=Sm–Nd Dating |date=2013 |url=https://doi.org/10.1007/978-94-007-6326-5_84-1 |encyclopedia=Encyclopedia of Scientific Dating Methods |pages=1–20 |editor-last=Rink |editor-first=W. Jack |access-date=2023-06-07 |place=Dordrecht |publisher=Springer Netherlands |language=en |doi=10.1007/978-94-007-6326-5_84-1 |isbn=978-94-007-6326-5 |editor2-last=Thompson |editor2-first=Jeroen}}</ref>
*Neodymium isotopes recorded in marine sediments are used to reconstruct changes in past ocean circulation.<ref>{{Cite journal|last=Tachikawa|first=K.|date=2003|title=Neodymium budget in the modern ocean and paleo-oceanographic implications|journal=Journal of Geophysical Research|volume=108|issue=C8|pages=3254|doi=10.1029/1999JC000285|bibcode=2003JGRC..108.3254T|doi-access=free}}</ref><ref>{{Cite journal|last1=van de Flierdt|first1=Tina|last2=Griffiths|first2=Alexander M.|last3=Lambelet|first3=Myriam|last4=Little|first4=Susan H.|last5=Stichel|first5=Torben|last6=Wilson|first6=David J.|date=2016-11-28|title=Neodymium in the oceans: a global database, a regional comparison and implications for palaeoceanographic research|journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences|volume=374|issue=2081|pages=20150293|doi=10.1098/rsta.2015.0293|pmid=29035258|pmc=5069528|bibcode=2016RSPTA.37450293V}}</ref>

==Biological role and precautions==
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The early lanthanides, including neodymium, as well as lanthanum, cerium and praseodymium, have been found to be essential to some [[methanotrophic]] bacteria living in [[Mudpot|volcanic mudpots]], such as ''[[Methylacidiphilum fumariolicum]]''.<ref>{{cite journal |doi=10.1111/1462-2920.12249 |pmid=24034209 |title=Rare earth metals are essential for methanotrophic life in volcanic mudpots |date=2013 |last1=Pol |first1=Arjan |last2=Barends |first2=Thomas R. M. |last3=Dietl |first3=Andreas |last4=Khadem |first4=Ahmad F. |last5=Eygensteyn |first5=Jelle |last6=Jetten |first6=Mike S. M. |last7=Op Den Camp |first7=Huub J. M. |journal=Environmental Microbiology |volume=16 |issue=1 |pages=255–64|bibcode=2014EnvMi..16..255P |url=https://repository.ubn.ru.nl//bitstream/handle/2066/128108/128108.pdf }}</ref><ref>{{Cite journal |last1=Kang |first1=Lin |last2=Shen |first2=Zhiqiang |last3=Jin |first3=Chengzhi |date=2000-04-01 |title=Neodymium cations Nd3+ were transported to the interior ofEuglena gracilis 277 |url=https://doi.org/10.1007/BF02886032 |journal=Chinese Science Bulletin |language=en |volume=45 |issue=7 |pages=585–592 |doi=10.1007/BF02886032 |bibcode=2000ChSBu..45..585K |s2cid=95983365 |issn=1861-9541}}</ref> Neodymium is not otherwise known to have a biological role in any other organisms.<ref>{{Cite journal |last1=Vais |first1=Vladimir |last2=Li |first2=Chunsheng |last3=Cornett |first3=Jack |date=2003-09-01 |title=Condensation reaction in the bandpass reaction cell improves sensitivity for uranium, thorium, neodymium and praseodymium measurements |url=https://doi.org/10.1007/s00216-003-2084-x |journal=Analytical and Bioanalytical Chemistry |language=en |volume=377 |issue=1 |pages=85–88 |doi=10.1007/s00216-003-2084-x |pmid=12856100 |s2cid=11330034 |issn=1618-2650}}</ref>

Neodymium metal dust is combustible and therefore an explosion hazard. Neodymium compounds, as with all rare-earth metals, are of low to moderate toxicity; however, its toxicity has not been thoroughly investigated. Ingested neodymium salts are regarded as more toxic if they are soluble than if they are insoluble.<ref>{{Cite web|url=https://www.lenntech.com/periodic/elements/nd.htm|title = Neodymium (Nd) - Chemical properties, Health and Environmental effects}}</ref> Neodymium dust and salts are very irritating to the eyes and [[mucous membrane]]s, and moderately irritating to skin. Breathing the dust can cause lung [[embolism]]s, and accumulated exposure damages the liver. Neodymium also acts as an [[anticoagulant]], especially when given intravenously.<ref name="history" />

Neodymium magnets have been tested for medical uses such as magnetic braces and bone repair, but [[biocompatibility]] issues have prevented widespread applications.<ref>{{Cite journal |last1=Donohue |first1=V. E. |last2=McDonald |first2=Fraser |last3=Evans |first3=R. |date=Mar 1995 |title=In vitro cytotoxicity testing of neodymium-iron-boron magnets |url=https://onlinelibrary.wiley.com/doi/10.1002/jab.770060110 |journal=Journal of Applied Biomaterials |language=en |volume=6 |issue=1 |pages=69–74 |doi=10.1002/jab.770060110 |pmid=7703540 |issn=1045-4861}}</ref> Commercially available magnets made from neodymium are exceptionally strong and can attract each other from large distances. If not handled carefully, they come together very quickly and forcefully, causing injuries. There is at least one documented case of a person losing a fingertip when two magnets he was using snapped together from 50&nbsp;cm away.<ref>{{cite web|last = Swain|first = Frank|title = How to remove a finger with two super magnets| publisher = Seed Media Group LLC|date = March 6, 2009|url = http://scienceblogs.com/sciencepunk/2009/03/06/how-to-remove-a-finger-with-tw/| access-date = 2013-03-31}}</ref>

Another risk of these powerful magnets is that if more than one magnet is ingested, they can pinch soft tissues in the [[gastrointestinal tract]]. This has led to an estimated 1,700 emergency room visits<ref name="times2014" /> and necessitated the recall of the [[Buckyball (toy)|Buckyballs line of toys]], which were construction sets of small neodymium magnets.<ref name="times2014">{{cite news|last = Abrams|first = Rachel|title = After Two-Year Fight, Consumer Agency Orders Recall of Buckyballs| newspaper = New York Times|date = July 17, 2014|url = https://www.nytimes.com/2014/07/18/business/after-two-year-fight-consumer-agency-orders-recall-of-buckyballs.html?_r=0| access-date = 2014-07-21}}</ref><ref>{{cite journal|title=Neodymium Magnets: Too Attractive?|date=2014|url=https://www.medscape.com/viewarticle/821835|journal=Medscape Gastroenterology|author=Balistreri, William F. }}</ref>

==See also==
*[[Neodymium compounds]]
*[[:Category:Neodymium compounds]]
*[[Lanthanide]]s
*[[Period 6 element]]s
*[[Rare earth metals]]

==Notes==
{{notelist}}

==References==
{{reflist|30em}}

==Bibliography==
*{{cite book|last1=Emsley|first1=John|title=Nature's Building Blocks: An A-Z Guide to the Elements|date=2011|publisher=[[Oxford University Press]]|isbn=978-0-19-960563-7}}
*{{Greenwood&Earnshaw2nd}}
* R. J. Callow, ''The Industrial Chemistry of the Lanthanons, Yttrium, Thorium, and Uranium'', Pergamon Press, 1967.
* {{cite journal |last1=Lodders |first1=K. |author1-link=Katharina Lodders |title=Solar System abundances and condensation temperatures of the elements |year=2003 |pages=1220–47 |journal=[[The Astrophysical Journal]] |volume=591 |issue=2 |issn=0004-637X |doi=10.1086/375492 |bibcode=2003ApJ...591.1220L |s2cid=42498829 |url=http://solarsystem.wustl.edu/wp-content/uploads/reprints/2003/Lodders%202003%20ApJ%20Elemental%20abundances.pdf }}

==External links==
{{Commons category|Neodymium}}
{{Wiktionary|neodymium}}
* [http://www.webelements.com/webelements/elements/text/Nd/index.html WebElements.com—Neodymium]
* [http://education.jlab.org/itselemental/ele060.html It's Elemental—The element Neodymium]
* [http://www.periodicvideos.com/videos/060.htm Neodymium] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)
*[http://environmentalchemistry.com/yogi/periodic/Nd.html EnvironmentalChemistry.com &ndash; Neodymium]
*[http://www.seltenerden.de?arg=zoom&element=Nd&art=121&seite=0&total=2#magnify&linkid=ewiki-Nd Pictures and more details about Neodymium metal]
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{{Periodic table (navbox)}}
{{Neodymium compounds}}

{{Authority control}}

[[Category:Neodymium| ]]
[[Category:Chemical elements]]
[[Category:Chemical elements with double hexagonal close-packed structure]]
[[Category:Energy development]]
[[Category:Lanthanides]]
[[Category:Reducing agents]]
[[Category:Renewable energy technology]]