Editing Berkelium (section)

===Bulk metal preparation===
In order to characterize chemical and physical properties of solid berkelium and its compounds, a program was initiated in 1952 at the [[Idaho National Laboratory|Material Testing Reactor]], [[Arco, Idaho]], US. It resulted in preparation of an eight-gram plutonium-239 target and in the first production of macroscopic quantities (0.6&nbsp;micrograms) of berkelium by Burris B. Cunningham and [[Stanley Gerald Thompson]] in 1958, after a continuous reactor irradiation of this target for six years.{{sfn|Peterson|Hobart|1984|p=30}}<ref>S. G. Thompson, BB Cunningham: "First Macroscopic Observations of the Chemical Properties of Berkelium and californium," supplement to Paper P/825 presented at the Second International Conference on Peaceful Uses of Atomic Energy, Geneva, 1958</ref> This irradiation method was and still is the only way of producing weighable amounts of the element, and most solid-state studies of berkelium have been conducted on microgram or submicrogram-sized samples.<ref name="H&P">{{cite book|first1 = David E.|last1 = Hobart|first2 = Joseph R.|last2 = Peterson|contribution = Berkelium|title = The Chemistry of the Actinide and Transactinide Elements|editor1-first = Lester R.|editor1-last = Morss|editor2-first = Norman M.|editor2-last = Edelstein|editor3-first = Jean|editor3-last = Fuger|edition = 3rd|date = 2006|volume = 3|publisher = Springer|location = Dordrecht, the Netherlands|pages = 1444–98|url = http://radchem.nevada.edu/classes/rdch710/files/berkelium.pdf|doi = 10.1007/1-4020-3598-5_10|isbn = 978-1-4020-3555-5|access-date = 30 September 2010|archive-date = 17 July 2010|archive-url = https://web.archive.org/web/20100717153832/http://radchem.nevada.edu/classes/rdch710/files/berkelium.pdf|url-status = dead}}</ref>{{sfn|Peterson|Hobart|1984|p=38}}

The world's major irradiation sources are the 85-megawatt High Flux Isotope Reactor at the [[Oak Ridge National Laboratory]] in Tennessee, USA,<ref>{{cite web|title = High Flux Isotope Reactor|url = http://neutrons.ornl.gov/facilities/HFIR/|publisher = Oak Ridge National Laboratory|access-date = 2010-09-23}}</ref> and the SM-2 loop reactor at the [[Research Institute of Atomic Reactors]] (NIIAR) in [[Dimitrovgrad, Russia]],<ref>{{cite web|title = Радионуклидные источники и препараты|url = http://www.niiar.ru/?q=radioisotope_application|publisher = Research Institute of Atomic Reactors|access-date = 2010-09-26}}</ref> which are both dedicated to the production of transcurium elements (atomic number greater than 96). These facilities have similar power and flux levels, and are expected to have comparable production capacities for transcurium elements,<ref name="Es">{{cite book|first = Richard G.|last = Haire|contribution = Einsteinium|title = The Chemistry of the Actinide and Transactinide Elements|editor1-first = Lester R.|editor1-last = Morss|editor2-first = Norman M.|editor2-last = Edelstein|editor3-first = Jean|editor3-last = Fuger|edition = 3rd|date = 2006|volume = 3|publisher = Springer|location = Dordrecht, the Netherlands|pages = 1577–1620|url = http://radchem.nevada.edu/classes/rdch710/files/einsteinium.pdf|doi = 10.1007/1-4020-3598-5_12|url-status = dead|archive-url = https://web.archive.org/web/20100717154427/http://radchem.nevada.edu/classes/rdch710/files/einsteinium.pdf|archive-date = 17 July 2010|isbn = 978-1-4020-3555-5}}</ref> although the quantities produced at NIIAR are not publicly reported. In a "typical processing campaign" at Oak Ridge, tens of grams of [[curium]] are irradiated to produce [[Kilogram#SI multiples|decigram]] quantities of [[californium]], [[Kilogram#SI multiples|milligram]] quantities of berkelium-249 and [[einsteinium]], and [[Kilogram#SI multiples|picogram]] quantities of [[fermium]].{{sfn|Greenwood|Earnshaw|1997|p=1262}}<ref>{{cite journal|first1 = C. E.|last1 = Porter|first2 = F. D. Jr. |last2 = Riley|first3 = R. D.|last3 = Vandergrift|first4 = L. K.|last4 = Felker|title = Fermium Purification Using Teva Resin Extraction Chromatography|journal = Sep. Sci. Technol.|volume = 32|issue = 1–4|date = 1997|pages = 83–92|doi = 10.1080/01496399708003188|url = https://zenodo.org/record/1234415}}</ref> In total, just over one gram of berkelium-249 has been produced at Oak Ridge since 1967.<ref name="H&P" />

The first berkelium metal sample weighing 1.7&nbsp;micrograms was prepared in 1971 by the reduction of {{Not a typo|berkelium(III)}} fluoride with [[lithium]] vapor at 1000&nbsp;°C; the fluoride was suspended on a tungsten wire above a [[tantalum]] crucible containing molten lithium. Later, metal samples weighing up to 0.5&nbsp;milligrams were obtained with this method.<ref name="Peterson">{{cite journal|last1 = Peterson|first1 = J. R.|last2 = Fahey|first2 = J. A.|last3 = Baybarz|first3 = R. D.|date = 1971|title = The crystal structures and lattice parameters of berkelium metal|journal = J. Inorg. Nucl. Chem.|volume = 33|issue = 10|pages = 3345–51|doi = 10.1016/0022-1902(71)80656-5}}</ref>{{sfn|Peterson|Hobart|1984|p=41}}
:{{chem2|BkF3 + 3 Li → Bk + 3 LiF}}

Similar results are obtained with {{Not a typo|berkelium(IV)}} fluoride.<ref name="pressure2">{{cite journal|last1=Itie|first1=J. P.|last2=Peterson|first2=J. R.|last3=Haire|first3=R. G.|last4=Dufour|first4=C.|last5=Benedict|first5=U.|journal=Journal of Physics F: Metal Physics|volume=15|pages=L213|date=1985|doi=10.1088/0305-4608/15/9/001|title=Delocalisation of 5f electrons in berkelium-californium alloys under pressure|issue=9|bibcode = 1985JPhF...15L.213I |url=https://zenodo.org/record/1235718}}</ref> Berkelium metal can also be produced by the reduction of {{Not a typo|berkelium(IV)}} oxide with [[thorium]] or [[lanthanum]].{{sfn|Peterson|Hobart|1984|p=41}}<ref>{{cite book|last1 = Spirlet|first1 = J. C.|last2 = Peterson|first2 = J. R.|last3 = Asprey|first3 = L. B.|date = 1987|title = Preparation and Purification of Actinide Metals|journal = Adv. Inorg. Chem.|volume = 31|pages = [https://archive.org/details/trent_0116400835595_31/page/1 1–41]|doi = 10.1016/S0898-8838(08)60220-2|series = Advances in Inorganic Chemistry|isbn = 9780120236312|url = https://archive.org/details/trent_0116400835595_31/page/1}}</ref>