Theoretical study of P2O5 polymorphs at high pressure: hexacoordinated phosphorus.
Theoretical study of P2O5 polymorphs at high pressure: hexacoordinated phosphorus.
复制标题
高压下 P2O5 多晶型物的理论研究：六配位磷。
作者：
M. A. Salvadó;P. Pertierra
13-15族元素的二元氧化物，从基本观点来看，以及它们作为原型、玻璃或半导体的基础的技术应用，都具有特殊的意义。氧化铝Al2O3以刚玉结构结晶，在低压和高压下均稳定，Al呈八面体配位。氧化硅SiO2在低压下以四面体Si配位相的形式结晶为α -石英，而在高压下以八面体Si配位相的形式稳定存在于硅辉石多晶态中。唯一已知的二磷氧化物具有四面体P配位。本文应用密度泛函理论方法，研究了P2O5不同相在高压下的稳定性，得到了局部密度、广义梯度近似和平面波基集。结果表明，高压下P2O5最稳定的形态可能是六配位磷。所有Al、Si和P的高压相都可以被描述为相同金红石型块的不同连接。
Binary oxides of elements belonging to groups 13-15 are of special relevance from a fundamental point of view as well as because of their technological applications as a basis in zeotypes, glasses, or semiconductors. Aluminum oxide, Al2O3, crystallizes in the corundum structure, which is stable at low and high pressures, with the Al showing octahedral coordination. Silicon oxide, SiO2, crystallizes in phases with tetrahedral Si coordination at low pressures as alpha-quartz, but at high pressures, octahedral coordination is stable in the stishovite polymorph. The only known binary phosphorus(V) oxides have tetrahedral P coordination. We have studied the stability of different phases of P2O5 at high pressure, applying density functional theory methodology within the local density and generalized gradient approximations and a plane-wave basis set. Our results indicate that the most stable form of P2O5 at high pressure could be one with hexacoordinated phosphorus. All of the high-pressure phases of Al, Si, and P can be described as a different linking of the same rutile-type blocks.