Potassium iodide

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White cubic crystals or powder that slowly turns yellow as it decomposes due to the release of iodine. Potassium iodide is used in the manufacture of photographic emulsions. It is also used in infrared spectroscopy to make transparent salt pellets. Potassium iodide, mixed with Iodine, is used as an indicator for Starch.

Synonyms and Related Terms

iodide of potass; potide

Chemical structure

Potassium iodide.jpg

Other Properties

Soluble in water, ethanol, acetone, glycerol. Incompatible with calomel, potassium chlorate, metallic salts, organic acids.

Composition KI
CAS 7681-11-0
Melting Point 686
Density 3.123
Molecular Weight mol. wt. = 166.0
Boiling Point 1330

Hazards and Safety

Slowly decomposes with moisture and light. Contact may cause irritation.

Mallinckrodt Baker: MSDS

Sources Checked for Data in Record

  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 7809
  • A Glossary of Paper Conservation Terms, Margaret Ellis (ed.), Conservation Center of the Institute of Fine Arts, New York City, 1998
  • Website address 1 Comment: photographic chemicals at www.jetcity.com/~mrjones/chemdesc.htm