Curium(IV) oxide

Curium(IV) oxide is an inorganic chemical compound of curium and oxygen with the chemical formula CmO₂. Since all isotopes of curium are man-made, the compound does not occur in nature.

Curium(IV) oxide

Names
Other names Curium dioxide
Identifiers
CAS Number	12016-67-0
3D model (JSmol)	Interactive image
ChemSpider	34998496
ECHA InfoCard	100.031.453
EC Number	234-612-6
PubChem CID	118856359 (charge error)
InChI InChI=1S/Cm.2O/q+4;2*-2 Key: GAFRKXHDERQHAP-UHFFFAOYSA-N
SMILES [O-2].[O-2].[Cm+4]
Properties
Chemical formula	CmO2
Molar mass	279 g·mol−1
Appearance	black crystals
Solubility in water	insoluble
Related compounds
Other cations	Americium(IV) oxide Berkelium(IV) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

• Curium(IV) oxide can be prepared directly from the elements. Metallic curium is annealed in air or in an oxygen atmosphere:^[1]

Cm + O₂ → CmO₂

• Curium(III) hydroxide and curium(III) oxalate are also usually used for this purpose:

Cm(OH)₄ → CmO₂ + 2H₂O

Cm(C₂O₄)₂ → CmO₂ + 2CO₂ + 2CO

• Another way is the reaction of curium(III) oxide in an oxygen atmosphere at 650 °C:^[2]

2Cm₂O₃ + O₂ → 4CmO₂

Physical properties

Curium(IV) oxide forms black crystals.^[3] Insoluble in water. The compound crystals are of the cubic crystal system, the fluorite structure in the space group Fm3m.

Chemical properties

The compound reacts with mineral acids to form solutions of curium(III) salts.^[4]

Uses

The compound is used for the manufacturing of isotopic current sources, also as targets for the synthesis of transcurium elements.