β-PtO2: High pressure synthesis of single crystals and structure refinement

High Pressure and Chemical Bonding in Materials Chemistry

“…In such a case, the coordination number of the B n+ most charged cations remains constant (VI), the electrostatic repulsions B n+ B n+ inducing the transition from face sharing octahedra (BX 6 common edges between (M 4+ F 6 ) and (Li + F 6 ) octahedra decreases with the M 4+ size or under high pressures for a constant M 4+ cation (Fig. 2) [4].…”

“…On the contrary PtO 2 -due to the smaller electronegativity difference between Pt and O (2.28 and 3.44, respectively) -can adopt at ambient pressure the layered CdI 2 -type structure (α-PtO 2 ) [5]. Under high pressure conditions -due to the enhancement of the electrostatic repulsion -the α-PtO 2 (CdI 2 -type) is transformed to the rutile form (β -PtO 2 ) [6]. First principles electronic calculations have recently confirmed the relative stabilities of the rutile and CdI 2 structural types versus the metal-oxygen and oxygen-oxygen orbital, interactions [7].…”

“…The high-pressure behaviour of the GdFeO 3 -type orthorhombic perovskites (ABO 3 ) -in particular the tilting of the (BO 6 ) octahedra -has recently been explained in terms of relative compressibilities of the (BO 6 ) and (AO 12 ) polyhedra. If the (BO 6 ) octahedra are less compressible than the (AO 12 ) dodecahedra the structural distortion is increased under high pressures.…”

Raman investigation of simple and complex oxides of platinum

“…This is an orthorhombic distortion of the rutile structure based on the space group 0 : : with 2 = 2. 17 The platinum atoms are in C2! sites and the oxygen atoms The Raman spectrum taken from a platinum foil which had been heated for 3 days at 1100 K in pure oxygen at a pressure of 700 atm is shown in Fig.…”

The Oxidation of Methane at Low Temperatures Over Zirconia-Supported Pd, Ir and Pt Catalysts and Deactivation by Sulfur Poisoning

“…Further investigation is required to clarify what types of interactions between Ir and Pt stabilize the high dispersion and the high oxidation states of Pt. Here, it is only noted that b-PtO 2 has a crystal structure (distorted rutile; a = 4.484 Å , b = 4.539 Å , c = 3.136 Å [24]) similar to IrO 2 (rutile; a = 4.505 Å , c = 3.159 Å ), and that IrO 2 is stable up to 1100°C whereas PtO 2 decomposes by releasing O 2 at 400°C [25].…”