Editing Berkelium (section)

===Separation===
The fact that berkelium readily assumes [[oxidation state]] +4 in solids, and is relatively stable in this state in liquids greatly assists separation of berkelium away from many other actinides. These are inevitably produced in relatively large amounts during the nuclear synthesis and often favor the +3 state. This fact was not yet known in the initial experiments, which used a more complex separation procedure. Various inorganic oxidation agents can be applied to the {{Not a typo|berkelium(III)}} solutions to convert it to the +4 state, such as [[bromate]]s ({{chem2|BrO3(-)}}), [[bismuthate]]s ({{chem2|BiO3(-)}}), [[Chromate and dichromate|chromate]]s ({{chem2|CrO4(2-)}} and {{chem2|Cr2O7(2−)}}), silver(I) thiolate ({{chem2|Ag2S2O8}}), lead(IV) oxide ({{chem2|PbO2}}), [[ozone]] ({{chem2|O3}}), or photochemical oxidation procedures. More recently, it has been discovered that some organic and bio-inspired molecules, such as the chelator called 3,4,3-LI(1,2-HOPO), can also oxidize Bk(III) and stabilize Bk(IV) under mild conditions.<ref name=":0">{{cite journal |last1=Deblonde |first1=Gauthier |last2=Sturzbecher-Hoehne |first2=Manuel |last3=Rupert |first3=Peter |last4=An |first4=Dahlia |last5=Illy |first5=Marie-Claire |last6=Ralston |first6=Corie |last7=brabec |first7=Jiri |last8=de Jong |first8=Wibe |last9=Strong |first9=Roland |last10=Abergel |first10=Rebecca |title=Chelation and stabilization of berkelium in oxidation state +IV |journal=Nature Chemistry |date=2017 |volume=9 |issue=9 |pages=843–849 |doi=10.1038/nchem.2759 |pmid=28837177 |bibcode=2017NatCh...9..843D |osti=1436161 |url=http://www.escholarship.org/uc/item/9zn3q96n }}</ref> {{Not a typo|Berkelium(IV)}} is then extracted with [[ion exchange]], extraction [[chromatography]] or liquid-liquid extraction using HDEHP (bis-(2-ethylhexyl) phosphoric acid), [[amine]]s, [[tributyl phosphate]] or various other reagents. These procedures separate berkelium from most trivalent actinides and [[lanthanide]]s, except for the lanthanide [[cerium]] (lanthanides are absent in the irradiation target but are created in various [[nuclear fission]] decay chains).{{sfn|Peterson|Hobart|1984|p=32}}

A more detailed procedure adopted at the [[Oak Ridge National Laboratory]] was as follows: the initial mixture of actinides is processed with ion exchange using [[lithium chloride]] [[reagent]], then precipitated as [[hydroxide]]s, filtered and dissolved in nitric acid. It is then treated with high-pressure [[elution]] from [[Ion exchange|cation exchange]] resins, and the berkelium phase is oxidized and extracted using one of the procedures described above.{{sfn|Peterson|Hobart|1984|p=32}} Reduction of the thus-obtained {{Not a typo|berkelium(IV)}} to the +3 oxidation state yields a solution, which is nearly free from other actinides (but contains cerium). Berkelium and cerium are then separated with another round of ion-exchange treatment.{{sfn|Peterson|Hobart|1984|pp=33–34}}