Californium compounds

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Few

cation.[2] The other two oxidation states are IV (strong oxidizing agents) and II (strong reducing agents).[3] The element forms a water-soluble chloride, nitrate, perchlorate, and sulfate and is precipitated as a fluoride, oxalate or hydroxide.[4] If problems of availability of the element could be overcome, then CfBr2 and CfI2 would likely be stable.[5]

Californium(III) nitrate

The +3 oxidation state is represented by californium(III) oxide (yellow-green, Cf2O3), californium(III) fluoride (bright green, CfF3) and californium(III) iodide (lemon yellow, CfI3).[3] Other +3 oxidation states include the sulfide and metallocene.[6] Californium(IV) oxide (black brown, CfO2), californium(IV) fluoride (green, CfF4) represent the IV oxidation state. The II state is represented by californium(II) bromide (yellow, CfBr2) and californium(II) iodide (dark violet, CfI2).[3]

Compounds

Californium(IV) oxide (CfO2) is a black-brown solid that has a cubic crystal structure with a lattice parameter, the distance between unit cells in the crystal, of 531.0 ± 0.2 pm.[7] Crystals of californium(III) oxide normally have a body-centered cubic symmetry. They convert to a monoclinic form upon heating to about 1400 °C and melt at 1750 °C.[7]

Californium(III) chloride (CfCl3) is an emerald green compound with a hexagonal structure that can be prepared by reacting Cf2O3 with hydrochloric acid at 500 °C.[8] CfCl3 is then used as a feeder stock to form the yellow-orange triiodide CfI3, which in turn can be reduced to the lavender-violet diiodide CfI2.[9]

Californium(IV) fluoride (CfF4) is a bright green solid with a monoclinic crystal structure.[11]

Californium(II) iodide (CfI2) is a deep purple solid with a stable rhombohedral structure at room temperature and an unstable hexagonal structure. Californium(III) iodide (CfI3) is a lemon-yellow solid that has a rhombohedral structure and sublimes at ~800 °C.[12]

Californium(III) oxyfluoride (CfOF) is prepared by hydrolysis of californium(III) fluoride (CfF3) at high temperature.[13] Californium(III) oxychloride (CfOCl) is prepared by hydrolysis of the hydrate of californium(III) chloride at 280–320 °C.[14]

Heating the sulfate in air at about 1200 °C and then reducing with hydrogen at 500 °C produces the sesquioxide (Cf2O3).[8] The hydroxide Cf(OH)3 and the trifluoride CfF3 are slightly soluble.[8]

Californium(III) oxychloride (CfOCl) was the first californium compound to be discovered.[15]

Californium(III) polyborate is unusual in that californium is covalently bound to the borate.[16]

Tris(cyclopentadienyl)californium(III) (Cp3Cf) presents itself as ruby red crystals. This cyclopentadienyl complex has been prepared by the reaction between Cp2Be and CfCl3 on a microgram scale and characterized by X-ray crystallography.[17] Californium is the second-heaviest element for which an organometallic compound is known. A bent californium metallocene has also been isolated and characterized.[18]

See also

References

  1. ISBN 978-0-313-33438-2
    .
  2. ^ CRC 2006, p. 4-8.
  3. ^ a b c Jakubke 1994, p. 166.
  4. ^ Seaborg 2004.
  5. ^ Greenwood 1997, p. 1272.
  6. ^ Cotton 1999, p. 1163.
  7. ^
    doi:10.1016/0022-1902(72)80435-4
    .
  8. ^ a b c Cunningham 1968, p. 105.
  9. ISBN 978-0-470-01006-8
    .
  10. doi:10.1016/0022-1902(73)80356-2
    .
  11. PMID 9993248
    .
  12. ISBN 978-0-412-30120-9
    .
  13. doi:10.1016/0022-1902(68)80155-1
    .
  14. doi:10.1016/0022-1902(69)80020-5
    .
  15. ^ Seaborg, Glenn T. (1963). Man-Made Transuranium Elements. Prentice-Hall.
  16. ^ "Unusual structure, bonding, and properties may provide a new possibility for a californium borate". 1 June 2015. Retrieved 29 July 2015.
  17. doi:10.1021/ic50087a018
    .
  18. S2CID 244347582
    .

Bibliography
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