Resorcinol blue

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Dark violet, flaky crystals. Resorcinol blue is used as an acid-base indicator. As a 0.2% ethanol solution, it is red at pH 4.4 and blue at pH 6.4. Resorcinol blue is also used as an indicator stain for proteins. It has been used as a direct dye for wool and silk fibers.

Synonyms and Related Terms

resorcin blue; lacmoid; iris blue B; fluorescent blue; CI 51400

Physical and Chemical Properties

Soluble in ethanol, ether, acetone, phenol, glacial acetic acid. Slightly soluble in water. Insoluble in chloroform, benzene, ligroin.

Composition (OH)2C6H3N[C6H2(OH)3]2