Structure and thermodynamic properties of zircon-coffinite solid solutions according to the semiempirical atomistic simulation data

被引：6

作者：

Zamyatin, D. A. ^{[1
]}

Shchapova, Yu. V. ^{[1
]}

Votyakov, S. L. ^{[1
]}

Eremin, N. N. ^{[2
]}

Urusov, V. S. ^{[2
]}

机构：

[1] Russian Acad Sci, Inst Geol & Geochem, Ural Branch, Ekaterinburg 620075, Russia

[2] Moscow MV Lomonosov State Univ, Dept Geol, Moscow 119991, Russia

来源：

GLASS PHYSICS AND CHEMISTRY | 2013年 / 39卷 / 02期

基金：

俄罗斯基础研究基金会;

关键词：

zircon; coffinite; solid solution; semiempirical atomistic simulation; GULP; parameters of potentials; local structure; thermodynamic parameters; mixing properties; solubility range; HIGH-URANIUM ZIRCON; THORITE; DIFFUSION; GRANITE; SYSTEM;

D O I：

10.1134/S108765961302017X

中图分类号：

TQ174 [陶瓷工业]; TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

Structure and thermodynamic properties of zircon, coffinite, and zircon-coffinite solid solutions were subject to semiempirical atomistic simulation on the assumption of compositional disordering of mixed crystals: (Zr1 - x , U (x) )SiO4, where x = 0.02, 0.05, 0.08, 0.11, 0.14, 0.28, 0.50, 0.72, and 0.86. The solid solutions significantly depart from the Vegard and Retgers laws. The (Zr1 - x , U (x) )SiO4 mixed crystal structure is characterized by anisotropic expansion (largely in the a and b directions) under growth in x related to anisotropy of structural relaxation degree of the cation-oxygen interatomic spacing in the (Zr, U)O-8 polyhedron. Increase in x parameters is accompanied by increase in average size of cation-oxygen polyhedrons and silica-oxygen tetrahedrons and by growth of interatomic spacing dispersion; maximum dispersion values are observed at x = 0.5-0.6. The distortions in local structures of ZrO8 and UO8 dodecahedrons and silica-oxygen tetrahedrons in the solid solution were analyzed on the basis of calculated functions of interatomic distance distribution. The obtained results demonstrate the possibility to assess numerically the structural (geometrical) disordering degree of the compositionally disordered solid solution depending on its composition. The calculated thermodynamic characteristics of solid solutions forecast the following solubility range limits: 2 mol % USiO4 in zircon and 5 mol % ZrSiO4 in coffinite under similar to 1750 K.

引用

页码：182 / 192

页数：11

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