Physical properties
Crystals with brilliant polychromism
(pleochroism), iridescent violet-blue on the prism faces, yellow-green in the axial direction.
Preparation
A solution of PtCl2 or K2PtCl4 is added to a cold, saturated
solution of KCN. The precipitated K2Pt(CN)4·3H2O is filtered off with suction. If it is to be used for preparing
the barium salt, it is dissolved in water and treated with a concentrated aqueous solution of BaCl2. The precipitated BaPt(CN)4·4H2O is filtered off with suction and washed with cold water.
