Stannous Chloride Dihydrate

Stannous Chloride Dihydrate BP Ph Eur
SnCl2,2H2O --- 225.6 --- CAS 10025-69-1

DEFINITION
Content: 98.0 per cent to 102.0 per cent.

CHARACTERS
Appearance: White or almost white, crystalline powder or colourless crystals, efflorescent in air.
Solubility: Freely soluble in water (the solution becomes cloudy after standing or on dilution), freely soluble in ethanol (96 per cent). It dissolves in dilute hydrochloric acid.

IDENTIFICATION
A. To 1 ml of solution S1 (see Tests) add 5 ml of water R and 0.05 ml of mercuric chloride solution R . A blackish-grey precipitate is formed.
B. Dissolve 1.0 g in 3.0 ml of water. Add 0.5 ml of dilute sodium hydroxide solution to the cloudy solution; a yellowish flocculent precipitate is formed. Add 6.5 ml of water. To 1.0 ml of the previously shaken suspension add 1.0 ml of strong sodium hydroxide solution; the precipitate dissolves and the resulting solution is clear and colourless.
C. Dissolve 10 mg in 2 ml of dilute nitric acid. The solution gives reaction (a) of chlorides.

TESTS
Solution S1: To 0.40 g add 1 ml of dilute hydrochloric acid R and dilute to 20 ml with distilled water R .
Solution S2: Dissolve 1.0 g in dilute hydrochloric acid R and dilute to 30 ml with the same acid. Heat to boiling. Add 30 ml of thioacetamide solution R and boil for 15 min (solution A). Take 5 ml, filter and heat the filtrate to boiling. Add 5 ml of thioacetamide solution R and boil for 15 min. If a precipitate is formed, add the remainder of solution A (solution A') to the mixture. Add 10 ml of thioacetamide solution R and boil. Repeat the series of operations from "Take 5 ml" until a precipitate is no longer formed on addition of thioacetamide solution R to the filtrate obtained from the 5 ml of solution A (solution A', solution A'', etc. respectively). If no precipitate is formed or if no more precipitate is formed combine the solution obtained with the remainder of solution A (solution A', solution A'', etc. respectively), filter and wash the precipitate with 10 ml of water R . Heat the filtrate until the resulting vapour no longer turns a moistened piece of lead acetate paper R blackish-grey. Allow to cool and dilute to 50 ml with water R.
Appearance of solution: The solution is clear and colourless.
Dissolve 10.0 g in dilute hydrochloric acid R and dilute to 20 ml with the same acid.
Substances not precipitated by thioacetamide: Maximum 0.2 per cent.
Evaporate 25 ml of solution S2 to dryness and ignite at 600±50C. The residue weighs a maximum of 1 mg.
Sulphates: Maximum 500 ppm, determined on solution S1.
Iron: Maximum 100 ppm.
Heavy metals: Maximum 50 ppm.