Appearance: Greenish-brown crystal.
Properties: Strong humidity--absorbability, and can produce itsdihydrate and hexahydrate. Easy soluble in water, ethanol, acetone,also in liquid sulfur dioxide, ethylamine, aniline; But insolublein glycerol, or phosphorus trichloride. Its aqueous solution isacidic.
Usage: Especially for water-treatment in industries, corrosive forelectronic printed board, chlorinating agent in metallurgicalindustry, oxidant and mordant in dye industry, and catalyst,oxidant, and chlorinating agent in organic synthesis, and also formaking ferric salt, pigment as raw material.