Pentachlor-palladates, M₂PdCl₆

When the sesquioxide, Pd₂O₃.xH₂O, is suspended in ether in the presence of rubidium chloride at the temperature of ether and solid carbon dioxide, small greyish green crystals of the double salt, Rubidium Pentachlor-palladate, 2RbCl.PdCl₃ or Rb₂PdCl₅, are obtained. Caesium yields an analogous salt, Cs₂PdCl₅, in the form of dark green crystals.

Both salts decompose in contact with water, the corresponding tetrachlor-palladites, Rb₂PdCl₄ and Cs₂PdCl₄ respectively, being obtained.

Potassium chloride, in similar circumstances, does not yield a pentachlor-palladate, but only the tetrachlor-palladite, K₂PdCl₄, and the double salt, PdCl₂.4KCl.