Nomenclature
CAS number: 7440-43-9
Description and references
Cd; at. wt 112.411; at. no. 48; valence 2.
Group IIB (12) element. Abundance in earth's crust: 0.1 to 0.2
ppm. Naturally occurring isotopes (mass numbers): 114 (28.73%);
112 (24.13%); 111 (12.80%); 110 (12.49%); 113 (12.22%), T 1/2 9.3 × 1015 yrs, β-emitter; 116 (7.49%); 106 (1.25%);
108 (0.89%); known artificial radioactive isotopes: 97-105, 107,
109, 115, 117-122, 124, 126. Found in zinc ores; also as CdS, greenockite;
CdCO3, otavite. Obtained in vapor form when roasting zinc
ores, as sludge from zinc sulfate purification. Lab prepns from CdSO4: Treadwell, Helv. Chim. Acta 4, 551 (1921). Implicated as causative agent in Itai-Itai
(“ouch-ouch”) disease in Japan: Flick et al., Environ. Res. 4, 71-85 (1971);
Fassett, Annu. Rev. Pharmacol. 15, 425-435 (1975). Review: Aylett “Group
IIB” in Comprehensive Inorganic Chemistry vol. 3, J. C. Bailar Jr. et al., Eds. (Pergamon
Press, Oxford, 1973) pp 187-328; D. S. Carr in Kirk-Othmer Encyclopedia of Chemical Technology vol. 4 (John Wiley & Sons, New York, 4th ed., 1992) pp
748-760; N. Herron, ibid. 760-776. Review of carcinogenic
risk: IARC Monographs 11, 39-74 (1976); and toxicity: Cadmium in
the Human Environment: Toxicity and Carcinogenicity, IARC Scientific
Publ. 118, G. F. Nordberg et al., Eds. (1992) 469 pp; of toxicology and human exposure: Toxicological Profile for Cadmium (PB99-166621,
1999) 439 pp.
Properties
Silver-white, blue-tinged, lustrous metal; distorted
hexagonal close-packed structure; easily cut with a knife; available
in the form of bars, sheets or wire or a gray, granular powder. mp 321°. bp 765°. d25 8.65. Specific heat at constant pressure
(25°) 6.22 cal/mole deg. Slowly oxidized by moist air to form CdO.
E° (aq) Cd/Cd2+ 0.4025 V. Insol in water. Reacts readily
with dil HNO3; reacts slowly with hot HCl; does not react
with alkalies. Other reactions similar to those of zinc. Solns of
cadmium salts and H2S or Na2S yield a yellow
ppt insol in excess Na2S.Caution
Overexposure to cadmium and cadmium
compounds has been associated with acute and chronic toxicity. Potential
symptoms of acute poisoning from the inhalation of cadmium dusts or
fumes include headache, chest pains, cough, metal fume fever, weakness.
Potential symptoms of acute poisoning from ingestion of cadmium salts
are GI disturbances, headache, muscular cramps, vertigo, convulsions.
Chronic inhalation may cause pulmonary emphysema and chronic bronchitis.
See Clinical Toxicology of Commercial
Products, R. E. Gosselin et al., Eds. (Williams
& Wilkins, Baltimore, 5th ed., 1984) Section II, p 99; Section
III, p 77-84. Potential toxic effects due to chronic overexposure
by inhalation or ingestion are anemia; kidney damage; osteomalacia
and osteoporosis. Itai-itai disease is a skeletal disease associated
with a cadmium-induced renal disorder and is attributed to high oral
intake of cadmium in food and water; characterized by progressive
bone demineralization with painful joints and bones. See Patty's Industrial Hygiene and Toxicology vol. 2C, G. D. Clayton, F. E. Clayton, Eds. (John Wiley
& Sons, New York, 4th ed., 1994) p 1954-1967. See also NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 44. Cadmium and cadmium compounds are
listed as known human carcinogens: Report
on Carcinogens, Eleventh Edition (PB2005-104914, 2004)
p III-42.Use
Batteries, including Ni-Cd storage batteries; coating
and electroplating steel and cast iron; pigments; plastic stabilizers;
constituent of low melting or easily fusible alloys, e.g., Lichtenberg's,
Abel's, Lipowitz', Newton's, and Wood's metal; electronics and optics;
soft solder and solder for aluminum; reactor control rods; hardener
for copper; catalytsts.
Therapeutic Category (Veterinary)
Many cadmium salts, especially the oxide
and anthranilate, are used or have been suggested as anthelmintics
in swine and poultry.