Cobaltous chloride

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Anhydrous cobalt (II) chloride


Pale blue, flaky crystals. Cobaltous chloride is most commonly used as a color indicator of moisture. On exposure to moist air, anhydrous cobaltous chloride absorbs water forming pink-color hexahydrate crystals. The blue anhydrous form can be regenerated by heating at 52-56 C. Cobaltous chloride is added to silica gel and activated alumina type desiccant as a moisture indicator. It has also been used in indicator paper.

Chemical structure

Cobaltous chloride.jpg

Synonyms and Related Terms

cobalt chloride; cobalt dichloride; cobalt (II) chloride; Cobalt(II)-chlorid (Deut.)


  • Skin contact may cause allergies, especially on elbows, neck and ankles.
  • Chronic inhalation may cause asthma.
  • Ingestion may cause vomiting, diarrhea and the sensation of hotness.
  • Fisher Scientific: MSDS

Physical and Chemical Properties

Soluble in water, alcohols, acetone, ether, glycerol, pyridine.

Composition CoCl2
CAS 7646-79-9
Melting Point 735 C
Density 3.348 g/ml
Molecular Weight mol. wt. = 129.84
Boiling Point 1049 C

Additional Images

Resources and Citations

  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 406
  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • The Dictionary of Paper, American Paper Institute, New York, Fourth Edition, 1980
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 2498
  • B. Gascoigne, How to Identify Prints, Thames & Hudson, London, 2004
  • CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: ref. index=