Chemical Properties
Gray-black powder. Soluble in water. Dissolves in ethanol to a blue color, dissolves in ethylene glycol ether to a brilliant blue color, and is insoluble in other organic solvents. Aqueous solution is purple, and upon addition of concentrated hydrochloric acid, it becomes reddish-blue. Addition of concentrated sodium hydroxide solution produces a reddish-purple color with a precipitate. In concentrated sulfuric acid, it exhibits a bluish-green color, turning purple upon dilution and forming a precipitate. Partially soluble in concentrated nitric acid, it exhibits an olive color. When dyed, it exhibits a slightly green color when exposed to copper ions and a slightly reddish-dark color when exposed to iron ions.
