Woot, another article to review! Looks like this is fairly decent for a little-known subject, of course hampered by the radioactivity, but never mind. Rainbow Dash is doing her /)^3^(\FreywaParclyTaxel 20% Cooler 06:09, 6 April 2012 (UTC)
Berkelium forms a number of chemical compounds where it normally exists in an oxidation state of +3 or +4 and behaves similarly to its lanthanide analogue, terbium. Insert commas.
Like all actinides, berkelium easily dissolves in various aqueous inorganic acids, liberating gaseous hydrogen and converting into the berkelium(III) state. Remove "and converting into the berkelium(III) state".
This trivalent oxidation state is most stable, especially in aqueous solutions, but tetravalent and possibly divalent berkelium compounds are also known. Replace first one with "the trivalent oxidation state formed is the" and remove the second one.
A similar behavior is observed for the lanthanide analogue of berkelium, terbium. Remove all this, it's repeated.
Berkelium does not react rapidly with oxygen at room temperature, possibly due to the formation of a protective oxide surface layer. However, it reacts with molten metals, hydrogen, halogens, chalcogens and pnictogens to form various binary compounds. Merge the two sentences and remove "possibly". FreywaParclyTaxel 20% Cooler 09:22, 6 April 2012 (UTC)
Two oxides of berkelium are known, with the Bk oxidation state of +3 (Bk2O3) and +4 (BkO2). Replace with "oxidation states".
It is a yellow-green solid with a melting point of 1920 °C, body-centered cubic crystal lattice and a lattice constant a = 1088.0 ± 0.5 pm. Rewrite "The compound has a melting point of 1920 °C and a body-centered cubic crystal lattice with lattice constant a = 1088.0 ± 0.5 pm."
Upon heating to 1200 °C, the cubic Bk2O3 transforms to a monoclinic structure, which further converts to a hexagonal phase at 1750 °C, and the latter transition is reversible. Replace second comma with semicolon and delete "and".
A divalent oxide BkO has been reported as a brittle gray solid with a face centered cubic (fcc) structure and a lattice constant a = 496.4 pm, but its exact chemical composition remains uncertain. Replace with "is". FreywaParclyTaxel 20% Cooler 09:28, 6 April 2012 (UTC)
The coordination of berkelium atom in its trivalent fluoride and chloride is tricapped trigonal prismatic, with the coordination number of 9. Insert "the" in the first expression and replace the second with "a".
In trivalent bromide, it is bicapped trigonal prismatic (coordination 8) or octahedral (coordination 6), and in the iodide it is octahedral. Replace with "the".
It can be prepared by introducing hydrogen chloride vapors into an evacuated quartz tube containing berkelium oxide at a temperature about 500 °C. Insert "of".
This green solid has a melting point of 603 °C and crystallized in the hexagonal crystal system isotypic with uranium(III) chloride (Pearson symbol hP8, space group P63/m, No. 176). Replace first one with "the" and second with "crystallises".
Upon heating to nearly melting point, BkCl3 converts into an orthorhombic phase. Remove - melting point is close enough.
Two forms of berkelium(III) bromide are known: a monoclinic with berkelium coordination 6 and orthorhombic with coordination 8; the latter is less stable and transforms to the former phase upon heating to about 350 °C. Replace colon with comma.
An important for radioactive solids phenomenon has been studies on example of these two crystal forms: the structure of fresh and aged 249BkBr3 samples was probed by X-ray diffraction over a period longer than 3 years, so that various fractions of 249Bk had beta decayed to 249Cf. Rewrite "The role of the decay of berkelium in the crystal structure has been studied by X-ray diffraction."
Beside a chemical contamination, 249Cf, as an alpha emitter brings undesirable self-damage of the crystal lattice and the resulting self-heating. Replace first one with "besides" and delete second one. Insert comma after "emitter".
The chemical effect however can be avoided by performing measurements as a function of time and extrapolating the obtained results. Replace with "this". FreywaParclyTaxel 20% Cooler 09:52, 6 April 2012 (UTC)
Pnictides and chalcogenides
The pnictides of berkelium-249 of the type BkX (where X is a pnictogen) are known for the elements nitrogen, phosphorus, arsenic and antimony. Remove.
They are prepared by the reaction of either berkelium(III) hydride (BkH3) or metallic berkelium with these elements at elevated temperature (about 600 °C) under high vacuum in quartz ampoules. Replace with "temperatures".
They crystallize in the rock-salt structure with the lattice constant of 495.1 pm for BkN, 566.9 pm for BkP, 582.9 for BkAs and 619.1 pm for BkSb. Replace with "cubic crystal structure".
These lattice constant values are smaller than those in curium pnictides but are comparable to those of terbium pnictides. Insert comma.
Berkelium(III) sulfide Bk2S3 was prepared by either treating berkelium oxide with a mixture of hydrogen sulfide and carbon disulfidevapors at 1130 °C, or by directly reacting metallic berkelium with sulfur. Insert comma and replace "was" with "has been".
These procedures yielded brownish-black crystals with a cubic symmetry and the lattice constant a = 844 pm. Replace first one with "yield" and remove second one.
Organometallic and other compounds
This compound is thermally stable to at least 1000 °C in inert atmosphere. Insert "an".
Berkelium forms a trigonal (η5–C5H5)3Bk complex with three cyclopentadienyl rings, which can be synthesized by reacting berkelium(III) chloride with the molten Be(C5H5)2 at about 70 °C. Er... this isn't beryllium. Replace with "Bk".
The high radioactivity of berkelium gradually destroys the compound (within a period of weeks). Remove parantheses.
One C5H5 ring in (η5–C5H5)3Bk can be substituted by chlorine to yield [Be(C5H5)2Cl]2. Again, replace with "Bk". FreywaParclyTaxel 20% Cooler 10:02, 6 April 2012 (UTC)