Monochlor-pentahydroxy-platinic Acid, H₂PtCl(OH)₅

Monochlor-pentahydroxy-platinic Acid, H₂PtCl(OH)₅, is obtained by the action of dilute sulphuric acid upon the barium salt. It is a brown, deliquescent syrup. It is dibasic in character. Its solutions decompose carbonates, slowly in the cold, but readily on warming.

The calcium salt is obtained by the action of sunlight on chlor-platinic acid in the presence of lime. The barium and strontium salts have likewise been obtained in a similar manner. If alkali hydroxides are employed, however, instead of the alkaline earths, similar salts are not obtained.