A new stacking variant of Na2Pt(OH)(6)

Abstract

A new stacking variant of sodium hexa-hydroxo platinate(IV), Na2Pt(OH)(6), was synthesized and its structure elucidated through X-ray diffraction. The new polymorph was prepared by direct reaction of PtO2 with an excess of NaOH solution applying elevated oxygen pressure at 300 degrees C. The structure consists of layers of edge sharing Pt(OH)(6) and Na(OH)(6) octahedra. These layers are separated by an edge-to-edge distance of similar to 2.4 angstrom. The packing of the hydroxide ions corresponds to the hcp sequence, the title compound thus may be regarded a cation ordered variant of the Brucite structure type. During heating above T 300 degrees C all constitutional water is released, and anhydrous Na2PtO3 remains as the solid residue.