Methyl violet 2B (Tetramethylparosanilinium chloride, 4,4′-[(4-imino-2,5-cyclohexadien-1-yliden)methylen]bis(N,N-dimethylaniline)hydrochloride) is a violet triarylmethane dye from the group of cationic dyes and an essential component of C.I.

Basic Violet 1 (trivial name methyl violet).

Methyl violets are mixtures of tetramethyl (2B), pentamethyl (6B) and hexamethyl (10B) pararosanilins.

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