Potassium Thio-palladite, K₂Pd₃S₄

Potassium Thio-palladite, K₂Pd₃S₄, is obtained as hexagonal needles on heating to redness a mixture of 1 part of palladous sulphide with 12 parts of a mixture containing caustic potash and sulphur in equal proportions. Extraction of the melt with water leaves a residue of crystalline thio-palladite. The crystals are insoluble in water, violet-blue in colour when moist, but metallic grey when dry. They dissolve, with decomposition, in hydrochloric acid.

The aqueous solution of potassium thio-palladite interacts with one of silver nitrate to yield insoluble hexagonal lamellae of Silver Тhio-palladite, Ag₂Pd₃S₄.