Nomenclature
CAS number: 7646-79-9
Cobalt chloride (CoCl
2); cobalt dichloride; cobalt(II) chloride.
Cl
2Co; mol wt 129.84.
Cl 54.61%, Co 45.39%.
CoCl
2.
Description and references
Prepn of anhydr from Co powder and Cl2: Osthoff, West, J. Am. Chem. Soc. 76, 4732 (1954); from the acetate and acetyl chloride:
Watt et al., ibid. 77, 2752 (1955); by dehydration of the hexahydrate with
SOCl2: Hecht, Z. Anorg. Chem. 254, 51 (1947). Prepn of the hexahydrate by treating
an aqueous soln of a cobaltous salt with HCl: ACS Monograph Series no. 149, entitled “Cobalt
- Its Chemistry, Metallurgy, and Uses,” R. S. Young, Ed. (Reinhold,
New York, 1960) p 76. Review: de Bie, Doyen, Cobalt 15, 3-13; 16, 3-15 (1962). Toxicity studies: G. J. A. Speijers et al., Food Chem. Toxicol. 20, 311 (1982); P. P. Singh, A. Y. Junnarkar, Indian J. Pharmacol. 23, 153 (1991). Review
of toxicology: B. Venugopal, T. D. Luckey, Environ. Qual. Safety Suppl. 1, 4-73 (1975).
Properties
Pale-blue hygroscopic leaflets; colorless in very
thin layers; turns pink on exposure to moist air. mp 735°; bp 1049°; d425 3.367. Dec 400° on long heating
in air. Sublimes at 500° in HCl gas, forming iridescent, fluffy,
colorless cryst. Sol in water, alcohols, acetone, ether, glycerol,
pyridine. LD50 in mice, rats (mg/kg): 360.0, 171.0 orally; 92.6, 36.9 i.p.; 23.3, 4.3 i.v. (Singh, Junnarkar).Derivative
Hexahydrate.
Nomenclature
CAS number: 7791-13-1
CoCl
2.6H
2O; mol wt 237.93.
Co 24.77%, Cl 29.80%, H 5.08%, O 40.35%.
Properties
Monoclinic crystals. Structure is reported to
be [CoCl2(H2O)4].2H2O:
Mizuno et al., J. Phys. Soc. Jpn. 14, 383 (1959), C.A. 53, 14630i (1959). Pink to red, slightly deliquesc,
monoclinic, prismatic crystals. mp 87°; d20 1.924. On heating loses 4H2O at 52-56° forming
the dihydrate, violet or blue crystals, d2525 2.477, stable unless
exposed directly to moisture. Loses another H2O by 100°,
giving monohydrate, violet, hygroscopic, amorphous solid or needles.
Remaining H2O lost at 120-140°. Sol in water, alcohols,
acetone, ether, glycerol. pH of 0.2 molar aq soln 4.6. The aq soln
is pink to red, but turns blue when heated or when HCl or H2SO4 is added. Keep well closed. LD50 orally in rats: 766 mg/kg (Speijers).Caution
Large amounts of CoCl2 depress erythrocyte production. May lead to death in children.
Other effects include cutaneous flushing, chest pains, dermatitides,
tinnitus, nausea and vomiting, nerve deafness, thyroid hyperplasia,
myxedema, congestive heart failure. See E. Beutler et al., Clinical Disorders of Iron
Metabolism (Grune & Stratton, New York, 1963) pp 175-178.Use
Invisible ink; humidity and water indicator; color
standard; in hygrometers; temp indicator in grinding; in electroplating;
for painting on glass and porcelain; prepn of catalysts; fertilizer
and feed additive; foam stabilizer in beer; as absorbent for military
poison gas and ammonia; in manuf of vitamin B
12. Radioactive
cobalt chloride,
57CoCl
2 (half-life 271.79 days,
pure gamma emitter) used in M"ossbauer effect (nuclear clock).
Therapeutic Category
Hematinic.
Therapeutic Category (Veterinary)
Nutritional factor. Used in cobalt deficiency
in ruminants.
Keywords
Hematinic