4043. Ferrous Chloride

Nomenclature

CAS number: 7758-94-3
Cl2Fe; mol wt 126.75.
Cl 55.94%, Fe 44.06%.
FeCl2.

Description and references

Occurs in nature as the mineral lawrencite. Preparation: Kovacic, Brace, Inorg. Synth. 6, 172 (1960); Kühnl, Ernst, Z. Anorg. Allg. Chem. 317, 84 (1962). Prepn of dihydrate: Gayer, Woontner, Inorg. Synth. 5, 179 (1957).

Properties

White rhombohedral crystals; may sometimes have a green tint. Very hygroscopic. mp 674°; bp 1023°; d25 3.16. Corrosive. Can be sublimed in a stream of HCl at about 700°. Forms FeCl3 and Fe2O3 on heating in air. Freely sol in water, alc, acetone; slightly sol in benzene. Practically insol in ether.

Derivative

Dihydrate.

Properties

White monoclinic crystals with pale green tint. Loses 1 H2O at 120°: Gayer, Woontner, loc. cit.; also reported to lose 1 H2O at 150-160°: Schafer, Z. Anorg. Allg. Chem. 258, 69 (1949). Sol in water.

Derivative

Tetrahydrate.

Properties

Pale green to blue-green, monoclinic crystals or cryst powder. Loses 2H2O at about 105-115°: Schafer, loc. cit. d 1.93. Sol in water, alcohol. The technical product may not be completely sol without the addn of acid. Aq solns are readily oxidized.

Caution

Potential symptoms of overexposure are irritation of eyes, skin, mucous membranes; abdominal pain, diarrhea, vomiting; possible liver damage. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 174.

Use

In metallurgy; as reducing agent; in pharmaceutical prepns; as mordant in dyeing.