Chromithiocyanic Acid, H₃[Cr(SCN)₆]

Chromithiocyanic Acid, H₃[Cr(SCN)₆], is formed in the deep wine-red solution which results from the decomposition of the lead or silver salt of this acid. The solution is strongly acid, but the compound has not been isolated, since on heating the solution gives off thiocyanic acid, and chromium thiocyanate remains behind. It forms salts containing the complex ion [Cr(SCN)₆]''', whose solutions, however, on long standing, especially under the influence of light, undergo ionic dissociation, as shown by freezing-point and conductivity determinations, and the resulting chemical activity. The salts of the heavy metals are of characteristic colours. The absorption spectra of some chromithiocyanates have been studied.