Property: White, yellow or red thin flake with an odor of rotten eggs; Easily soluble in water, presenting strong alkaline solution; Easily oxidized when exposed in air; Contact with acids releases poisonous gas (H2S). Corrosive, cause burns; Harmful, if swallowed. Use in dyestuff industry, tanning industry, leather industry, textile industry, pigment and rubber industry etc. It is also used as raw material to produce sodium thiosulfate, sodium hydrosulfide.