Sodium tetrachloropalladate is an inorganic compound with the chemical formula Na<sub>2</sub>PdCl<sub>4</sub>. The compound crystallizes from water as a reddish-brown trihydrate (Na<sub>2</sub>PdCl<sub>4</sub>÷3H<sub>2</sub>O), which is the commercially available form. According to X-ray crystallography, the PdCl<sub>4</sub><sup>2-</sup> centers adopt square planar molecular geometry with Pd-Cl distances of 231 picometers.
This salt, and the analogous alkali metal salts of the form M<sub>2</sub>PdCl<sub>4</sub>, may be prepared simply by reacting palladium(II) chloride with the appropriate alkali metal chloride in aqueous solution. Palladium(II) chloride is insoluble in water, whereas the product dissolves:
This compound may further react with phosphines to give phosphine complexes of palladium.
An alternative method of preparing such phosphine complexes is to break up the coordination polymer of palladium(II) chloride into reactive, monomeric acetonitrile or benzonitrile complexes, followed by reaction with phosphines.