H 2 0],thechlorpentammine or purpureo-chromium salts, R 1 2 [Cr(NH 3) 5 Cl], the nitrito pentammine or xanthochromium salts, R 1 2[N02 (NH3)5 Cr], the luteo or hexammine chromium salts, R 1 3[(NH3) 6 Cr], and the rhodochromium salts: where R 1 = a monovalent acid radical and M = a monovalent basic radical.
The pentammine purpureo-salts are formed from the luteo-salts by loss of ammonia, or from an air slowly oxidized ammoniacal cobalt salt solution, the precipitated luteosalt being filtered off and the filtrate boiled with concentrated acids.
They are formed by the action of nitrous fumes on ammoniacal solutions of cobaltous salts, or purpureo-salts, or by the mutual reaction of chlorpurpureosalts and alkaline nitrites.
They are of a reddish colour and usually crystallize well; on heating with concentrated acids are usually transformed into the purpureo-salts.
How would you define purpureo? Add your definition here.