Cadmium oxide
Cadmium oxide is an inorganic compound with the formula CdO. It is one of the main precursors to other cadmium compounds. It crystallizes in a cubic rocksalt lattice like sodium chloride, with octahedral cation and anion centers. It occurs naturally as the rare mineral monteponite. Cadmium oxide can be found as a colorless amorphous powder or as brown or red crystals. Cadmium oxide is an n-type semiconductor with a band gap of 2.18 eV (2.31 eV) at room temperature (298 K).
| Names | |
|---|---|
| IUPAC name
Cadmium oxide | |
| Other names
Cadmium(II) oxide, Cadmium monoxide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.013.770 |
| EC Number |
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PubChem CID |
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| RTECS number |
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| UNII | |
| UN number | 2570 |
CompTox Dashboard (EPA) |
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| Properties | |
| CdO | |
| Molar mass | 128.413 g·mol−1 |
| Appearance | colorless powder (alpha form) red-brown crystal (beta form) |
| Odor | odorless |
| Density | 8.15 g/cm3(crystalline), 6.95 g/cm3 (amorphous) solid. |
| Melting point | 900–1,000 °C (1,650–1,830 °F; 1,170–1,270 K) decomposition of amorphous form |
| Boiling point | 1,559 °C (2,838 °F; 1,832 K) sublimation |
| 4.8 mg/L (18 °C) | |
| Solubility | soluble in dilute acid slowly soluble in ammonium salts insoluble in alkalies |
| Vapor pressure | 0.13 kPa (1000 °C) 2.62 kPa (1200 °C) 61.4 kPa (1500 °C) |
| Band gap | 2.18 eV |
| Electron mobility | 531 cm2/V·s |
| -3.0·10−5 cm3/mol | |
| Thermal conductivity | 0.7 W/m·K |
Refractive index (nD) |
2.49 |
| Structure | |
| cubic, cF8 | |
| Fm3m, No. 225 | |
a = 4.6958 Å | |
| Thermochemistry | |
Heat capacity (C) |
43.64 J/mol·K |
Std molar entropy (S⦵298) |
55 J/mol·K |
Std enthalpy of formation (ΔfH⦵298) |
−258 kJ/mol |
Gibbs free energy (ΔfG⦵) |
-229.3 kJ/mol |
| Hazards | |
| GHS labelling: | |
| Danger | |
| H330, H341, H350, H361, H372, H410 | |
| P201, P260, P273, P281, P284, P310 | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
72 mg/kg (oral, rat) 72 mg/kg (oral, mouse) |
LC50 (median concentration) |
500 mg/m3 (rat, 10 min) 2500 mg/m3 (rabbit, 10 min) 3500 mg/m3 (guinea pig, 10 min) 4000 mg/m3 (dog, 10 min) 780 mg/m3 (rat, 10 min) 340 mg/m3 (mouse, 10 min) 3000 mg/m3 (rabbit, 15 min) 3000 mg/m3 (guinea pig, 15 min) 400 mg/m3 (dog, 10 min) |
| NIOSH (US health exposure limits): | |
PEL (Permissible) |
[1910.1027] TWA 0.005 mg/m3 (as Cd) |
REL (Recommended) |
Ca |
IDLH (Immediate danger) |
Ca [9 mg/m3 (as Cd)] |
| Safety data sheet (SDS) | |
| Related compounds | |
Other anions |
Cadmium sulfide Cadmium selenide Cadmium telluride |
Other cations |
Zinc oxide Mercury oxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
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