Title: Mercuric Iodide, Red

CAS Registry Number: 7774-29-0

Additional Names: Mercury biniodide

Molecular Formula: HgI2

Molecular Weight: 454.40

Percent Composition: Hg 44.14%, I 55.86%

Properties: Scarlet-red, heavy, odorless, almost tasteless powder; sensitive to light; at 130° becomes yellow, and then red on cooling. Poisonous! d 6.28. mp 259°. bp ~350° and sublimes. Soly in water (25°) 0.006 g/100 g. 1 g dissolves in 115 ml alcohol, 20 ml boiling alcohol, about 120 ml ether, about 60 ml acetone, 910 ml chloroform, 75 ml ethyl acetate, 260 ml carbon disulfide, readily in alkali iodides, HgCl2, Na2S2O3; sol in 230 ml olive oil, 50 ml castor oil. Protect from light.

Melting point: mp 259°

Boiling point: bp ~350° and sublimes

Density: d 6.28

Use: In anal. chemistry for preparation of Nessler's Reagent (alkaline mercuric potassium iodide solution).

Therap-Cat: Antiseptic (topical).

Therap-Cat-Vet: Has been used as a topical antiseptic, counterirritant, vesicant.