Karazhanov S Zh, Ravindran P, Vajeeston P, Ulyashin A G, Fjellvåg H, Svensson B G
Centre for Material Science and Nanotechnology, Department of Chemistry, University of Oslo, PO Box 1033 Blindern, N-0315 Oslo, Norway. Institute for Energy Technology, PO Box 40, N-2027 Kjeller, Norway. Physical-Technical Institute, 2B Mavlyanov Street, Tashkent 700084, Uzbekistan.
J Phys Condens Matter. 2009 Dec 2;21(48):485801. doi: 10.1088/0953-8984/21/48/485801. Epub 2009 Nov 6.
Using density functional total energy calculations the structural phase stability and pressure-induced structural transition in different polymorphs of ZnSiO(3) and Zn(2)SiO(4) have been studied. Among the considered monoclinic phase with space groups (P 2(1)/c) and (C 2/c), rhombohedral [Formula: see text] and orthorhombic (Pbca) modifications the monoclinic phase (P 2(1)/c) of ZnSiO(3) is found to be the most stable one. At high pressure monoclinic ZnSiO(3) (C 2/c) can co-exist with orthorhombic (Pbca) modification. Differences in equilibrium volume and total energy of these two polymorphs are very small, which indicates that it is relatively easier to transform between these two phases by temperature, pressure or chemical composition. It can also explain the experimentally established result of metastability of the orthorhombic phase under all conditions. The following sequence of pressure-induced structural phase transitions is found for ZnSiO(3) polymorphs: monoclinic [Formula: see text] monoclinic [Formula: see text] rhombohedral [Formula: see text]. Among the rhombohedral ([Formula: see text]), tetragonal [Formula: see text], orthorhombic (Pbca), orthorhombic (Imma), cubic [Formula: see text] and orthorhombic (Pbnm) modifications of Zn(2)SiO(4), the rhombohedral phase is found to be the ground state. For this chemical composition of zinc silicate the following sequence of structural phase transitions is found: rhombohedral [Formula: see text] tetragonal [Formula: see text] orthorhombic [Formula: see text] orthorhombic (Imma) [Formula: see text] cubic [Formula: see text] orthorhombic (Pbnm). Based on the analogy of crystal structures of magnesium and zinc silicates and using the lattice and positional parameters of Mg(2)SiO(4) as input, structural properties of spinel Zn(2)SiO(4) have also been studied.
通过密度泛函总能量计算，研究了硅酸锌（ZnSiO₃）和硅酸锌（Zn₂SiO₄）不同多晶型物的结构相稳定性和压力诱导的结构转变。在所考虑的具有空间群（P 2(1)/c）和（C 2/c）的单斜相、菱面体[化学式：见原文]和正交（Pbca）变体中，发现硅酸锌（ZnSiO₃）的单斜相（P 2(1)/c）是最稳定的。在高压下，单斜硅酸锌（C 2/c）可以与正交（Pbca）变体共存。这两种多晶型物的平衡体积和总能量差异非常小，这表明通过温度、压力或化学成分在这两个相之间转变相对更容易。这也可以解释在所有条件下正交相亚稳性的实验结果。对于硅酸锌（ZnSiO₃）多晶型物，发现了以下压力诱导的结构相转变顺序：单斜[化学式：见原文]单斜[化学式：见原文]菱面体[化学式：见原文]。在硅酸锌（Zn₂SiO₄）的菱面体（[化学式：见原文]）、四方[化学式：见原文]、正交（Pbca）、正交（Imma）、立方[化学式：见原文]和正交（Pbnm）变体中，发现菱面体相是基态。对于这种硅酸锌的化学成分，发现了以下结构相转变顺序：菱面体[化学式：见原文]四方[化学式：见原文]正交[化学式：见原文]正交（Imma）[化学式：见原文]立方[化学式：见原文]正交（Pbnm）。基于镁和锌硅酸盐晶体结构的类比，并使用Mg₂SiO₄的晶格和位置参数作为输入，还研究了尖晶石Zn₂SiO₄的结构性质。
