Californium compounds

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Few compounds of californium have been made and studied. [1] The only californium ion that is stable in aqueous solutions is the californium(III) 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]

Contents

Californium(III) nitrate Cf-251.png
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(III) fluoride (CfF3) is a yellow-green solid with a crystal symmetry that gradually changes from orthorhombic to trigonal when heated above room temperature. [10] 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

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<span class="mw-page-title-main">Berkelium compounds</span> Any chemical compound having at least one berkelium atom

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<span class="mw-page-title-main">Californium(III) oxychloride</span> Chemical compound

Californium oxychloride is a radioactive salt first discovered in measurable quantities in 1960. It is composed of a single californium cation and oxychloride consisting of one chloride and one oxide anion. It was the first californium compound ever isolated.

Californium(III) chloride is an inorganic compound with a chemical formula CfCl3. Like in californium oxide (Cf2O3) and other californium halides, including californium fluoride (CfF3) and iodide (CfI3), the californium atom has an oxidation state of +3.

<span class="mw-page-title-main">Californium(III) bromide</span> Chemical compound

Californium(III) bromide is an inorganic compound, a salt with a chemical formula CfBr3. Like in californium oxide (Cf2O3) and other californium halides, including californium(III) fluoride (CfF3), californium(III) chloride, and californium(III) iodide (CfI3), the californium atom has an oxidation state of +3.

Curium compounds are compounds containing the element curium (Cm). Curium usually forms compounds in the +3 oxidation state, although compounds with curium in the +4, +5 and +6 oxidation states are also known.

Praseodymium compounds are compounds formed by the lanthanide metal praseodymium (Pr). In these compounds, praseodymium generally exhibits the +3 oxidation state, such as PrCl3, Pr(NO3)3 and Pr(CH3COO)3. However, compounds with praseodymium in the +2 and +4 oxidation states, and unlike other lanthanides, the +5 oxidation state, are also known.

Einsteinium compounds are compounds that contain the element einsteinium (Es). These compounds largely have einsteinium in the +3 oxidation state, or in some cases in the +2 and +4 oxidation states. Although einsteinium is relatively stable, with half-lives ranging from 20 days upwards, these compounds have not been studied in great detail.

<span class="mw-page-title-main">Europium compounds</span> Compounds with at least one europium atom

Europium compounds are compounds formed by the lanthanide metal europium (Eu). In these compounds, europium generally exhibits the +3 oxidation state, such as EuCl3, Eu(NO3)3 and Eu(CH3COO)3. Compounds with europium in the +2 oxidation state are also known. The +2 ion of europium is the most stable divalent ion of lanthanide metals in aqueous solution. Many europium compounds fluoresce under ultraviolet light due to the excitation of electrons to higher energy levels. Lipophilic europium complexes often feature acetylacetonate-like ligands, e.g., Eufod.

<span class="mw-page-title-main">Lanthanum(III) iodide</span> Chemical compound

Lanthanum(III) iodide is an inorganic compound containing lanthanum and iodine with the chemical formula LaI
3.

Lutetium compounds are compounds formed by the lanthanide metal lutetium (Lu). In these compounds, lutetium generally exhibits the +3 oxidation state, such as LuCl3, Lu2O3 and Lu2(SO4)3. Aqueous solutions of most lutetium salts are colorless and form white crystalline solids upon drying, with the common exception of the iodide. The soluble salts, such as nitrate, sulfate and acetate form hydrates upon crystallization. The oxide, hydroxide, fluoride, carbonate, phosphate and oxalate are insoluble in water.

Americium compounds are compounds containing the element americium (Am). These compounds can form in the +2, +3, and +4, although the +3 oxidation state is the most common. The +5, +6 and +7 oxidation states have also been reported.

<span class="mw-page-title-main">Californium(III) fluoride</span> Chemical compound

Californium(III) fluoride is a binary inorganic compound of californium and fluorine with the formula CfF
3

Californium(III) oxide is a binary inorganic compound of californium and oxygen with the formula Cf
2O
3. It is one of the first obtained solid compounds of californium, synthesized in 1958.

Californium(II) iodide is a binary inorganic compound of californium and iodine with the formula CfI
2.

References

  1. ↑ Krebs, Robert (2006). The History and Use of our Earth's Chemical Elements: A Reference Guide . Westport, Connecticut: Greenwood Publishing Group. pp.  327–328. ISBN   978-0-313-33438-2.
  2. ↑ CRC 2006, p. 4-8.
  3. 1 2 3 Jakubke 1994, p. 166.
  4. ↑ Seaborg 2004.
  5. ↑ Greenwood 1997, p. 1272.
  6. ↑ Cotton 1999, p. 1163.
  7. 1 2 Baybarz, R. D.; Haire, R. G.; Fahey, J. A (1972). "On the Californium Oxide System". Inorganic and Nuclear Chemistry . 34 (2): 557–565. doi:10.1016/0022-1902(72)80435-4.
  8. 1 2 3 Cunningham 1968, p. 105.
  9. ↑ Cotton, Simon (2006). Lanthanide and Actinide Chemistry. West Sussex, England: John Wiley & Sons. p. 168. ISBN   978-0-470-01006-8.
  10. ↑ Stevenson, J. N.; Peterson, J. R. (1973). "The Trigonal and Orthorhombic Crystal Structures of CfF3 and their Temperature Relationship". Inorganic and Nuclear Chemistry . 35 (10): 3481–3486. doi:10.1016/0022-1902(73)80356-2.
  11. ↑ Chang, C-T. P.; Haire, R. G.; Nave, S. E. (1990). "Magnetic Susceptibility of Californium Fluorides". Physical Review B. 41 (13): 9045–9048. Bibcode:1990PhRvB..41.9045C. doi:10.1103/PhysRevB.41.9045. PMID   9993248.
  12. ↑ Macintyre, J. E.; Daniel, F. M.; Stirling, V. M. (1992). Dictionary of inorganic compounds. London: Chapman and Hall, CRC Press. p. 2826. ISBN   978-0-412-30120-9.
  13. ↑ Peterson, J. R.; Burns, John H. (1968). "Preparation and Crystal Structure of Californium Oxyfluoride, CfOF". Inorganic and Nuclear Chemistry . 30 (11): 2955–2958. doi:10.1016/0022-1902(68)80155-1.
  14. ↑ Copeland, J. C.; Cunningham, B. B. (1969). "Crystallography of the Compounds of Californium. II. Crystal Structure and Lattice Parameters of Californium Oxychloride and Californium Sesquioxide" (PDF). Inorganic and Nuclear Chemistry . 31 (3): 733–740. 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. ↑ Laubereau, Peter G.; Burns, John H. (1970). "Microchemical preparation of tricyclopentadienyl compounds of berkelium, californium, and some lanthanide elements". Inorganic Chemistry. 9 (5): 1091–1095. doi:10.1021/ic50087a018.
  18. ↑ Goodwin, Conrad A. P.; Su, Jing; Stevens, Lauren M.; White, Frankie D.; Anderson, Nickolas H.; Auxier, John D.; Albrecht-Schönzart, Thomas E.; Batista, Enrique R.; Briscoe, Sasha F.; Cross, Justin N.; Evans, William J.; Gaiser, Alyssa N.; Gaunt, Andrew J.; James, Michael R.; Janicke, Michael T.; Jenkins, Tener F.; Jones, Zachary R.; Kozimor, Stosh A.; Scott, Brian L.; Sperling, Joseph. M.; Wedal, Justin C.; Windorff, Cory J.; Yang, Ping; Ziller, Joseph W. (18 November 2021). "Isolation and characterization of a californium metallocene" (PDF). Nature. 599 (7885): 421–424. Bibcode:2021Natur.599..421G. doi:10.1038/s41586-021-04027-8. PMID   34789902. S2CID   244347582.

Bibliography

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