Solochrome Dark Blue

CI 15705; calcon; mordant black 17; C₂₀H₁₃N₂NaO₅S = 416.4 (2538-85-4)

General reagent grade of commerce.

A brownish black powder with a violet sheen. Produces a purplish red colour with calcium ions in alkaline solutions. When metal ions are absent, for example, in the presence of an excess of disodium edetate, the solution is blue.