A Structure-mineralogical Study of Ringwoodite  

作　　者：傅平秋 谢鸿森 章礼明 

机构地区：[1]Institute of Geochemistry,Academia Sinica

出　　处：《Chinese Journal Of Geochemistry》1990年第2期99-104,共6页中国地球化学学报

摘　　要：The powder XRD analysis of ringwoodite(γ-Fe2SiO4),which was synthesized in a II-stage anvil high-pressure capsule,was made,Its unit-cell parameter was calculated:a=8.219A,After the refinements,for several cycles,of the oxygen parameter x and the occupancy rate of Si in octahedron site,i.e.,the iversion degree u,the final result is R=0.077,when x=0.379A and u=27.5%,with the structural formula (Fe1.725 Si0.275)VI(Si0.725Fe0.275)IV O4 and atomic distances(Fe,Si)VI-O=2.022 A and (Si,Fe)IV-O=1.836A,Meanwhile,the Moessbauer spectroscopic analysis of the sample was conducted and the results obtained are in good agreement with those of X-ray structural analysis ,This paper focuses on the phase transformation and the properties of bonds of α－Fe2SiO4→γ-Fe2SiO4.The powder XRD analysis of ringwoodite (γ-Fe_2SiO_4),which was synthesized in a Ⅱ-stage anvil high-pressure capsule.was made.Its unit-cell parameter was calculated:a=8.219 .After the refinements, for several cycles,of the oxygen parameter χ and the occupancy rate of Si in octahedron site,i.e.,the iversion degree u,the final result is R=0.077,when χ=0,379 A and u=27.5%,with the structural formula (Fel.725 Si_0.275)~VI(Si_0.725 Fe_0.275)~VI O_4 and atomic distances (Fe,Si)~VI O=2.022 and (Si,Fe)~VI-O =1. 836.Meanwhile,the Mssbauer spectroscopic analysis of the sample was conducted and the results obtained are in good agreement with those of X-ray structural analysis.This paper focuses on the phase transformation and the properties of bonds ofα-Fe_2SiO_4→γ-Fe_2SiO_4.

关 键 词：矿物学研究 X射线结构分析 XRD分析 橄榄石 晶胞参数 

分 类 号：P575.5[天文地球—矿物学]