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Cadmium oxide

Cadmium oxide
Oxid kademnatý.JPG
NaCl polyhedra.png
Names
IUPAC name
Cadmium oxide
Other names
Cadmium(II) oxide,
Cadmium monoxide
Identifiers
1306-19-0 YesY
3D model (Jmol) Interactive image
ChemSpider 14099 YesY
ECHA InfoCard 100.013.770
EC Number 215-146-2
PubChem 14782
RTECS number EV1925000
UN number 2570
Properties
CdO
Molar mass 128.41 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</sup cm3/mol
Thermal conductivity 0.7 W/m·K
2.49
Structure
cubic, cF8
Fm3m, No. 225
a = 4.6958 Å
Thermochemistry
43.64 J/mol·K
55 J/mol·K
−258 kJ/mol
-229.3 kJ/mol
Hazards
Safety data sheet [1]
GHS pictograms The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word Danger
H330, H341, H350, H361, H372, H410
P201, P260, P273, P281, P284, P310
Very Toxic T+ Dangerous for the Environment (Nature) N
Carc. Cat. 2
Muta. Cat. 3
Repr. Cat. 3
R-phrases R45, R26, R48/23/25, R62, R63, R68, R50/53
S-phrases S53, S45, S60, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)
 72 mg/kg (oral, rat)
72 mg/kg (oral, mouse)
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)
US health exposure limits (NIOSH):
PEL (Permissible)
 [1910.1027] TWA 0.005 mg/m3 (as Cd)
REL (Recommended)
 Ca
IDLH (Immediate danger)
 Ca [9 mg/m3 (as Cd)]
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).
YesY  (what is YesYN ?)
Infobox references

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).

Since cadmium compounds are often found in association with zinc ores, cadmium oxide is a common by-product of zinc refining. It is produced by burning elemental cadmium in air. Pyrolysis of other cadmium compounds, such as the nitrate or the carbonate, also affords this oxide. When pure, it is red, but CdO is unusual in being available in many differing colours due to its tendency to form defect structures resulting from anion vacancies. Cadmium oxide is prepared commercially by oxidizing cadmium vapor in air.

Cadmium oxide is used in cadmium plating baths, electrodes for storage batteries, cadmium salts, catalyst, ceramic glazes, phosphors, and nematocide. Major uses for cadmium oxide are as an ingredient for electroplating baths, and in pigments.

CdO is used as a transparent conductive material, which was prepared as a transparent conducting film as early as 1907 by Karl Baedeker. Cadmium oxide in the form of thin films has been used in applications such as photodiodes, phototransistors, photovoltaic cells, transparent electrodes, liquid crystal displays, IR detectors, and anti reflection coatings. CdO microparticles undergo bandgap excitation when exposed to UV-A light and is also selective in phenol photodegradation.


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