Editing Neodymium (section)

==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}}