摘要
硅铁灰石产于云南昭通莲峰二叠纪峨眉山玄武岩的晶洞中,晶体以(100)发育的板状、薄板状、厚板状、板柱状为主,根据电子探针成分数据,按阴离子数O15计算出所研究硅铁灰石的矿物分子式:Ca2.037(Fe20.+709Mn02.+187Mg20.+063)0.959Fe31.+182[(Si4.997Al0.003)5.0O14.768(OH)0.232]。采用侧槽装样法制备晶体结构解析用样片,使用X′Pert PRO型X射线粉晶衍射仪收集衍射数据,通过模型法和Rietveld结构精修方法精修了硅铁灰石的晶体结构,并收敛到Rp=0.035 1,Rwp=0.045 4,Rexp=0.028 86,χ2=2.475。精修后硅铁灰石的空间群为P1,a=0.746 6(1)nm,b=1.163 1(2)nm,c=0.668 4(1)nm,α=91.554(4)°,β=93.889(3)°,γ=104.193(3)°。硅铁灰石晶体单胞由铁氧八面体与钙氧十二面体连接沿[110]方向延伸的两条硅氧四面体单链组成,其中,铁氧八面体和钙氧十二面体都存在不同程度的畸变。
The babingtonite occurred in the drusy cavities of permian period Emeishan basalt, Yunnan province. Its crystal habit is tabular and prismatic, parallel with crystal face (100). The resulting chemical formulaof the Emeishan babingtonite sample is Ca2.037(Fe^2+0.709Mn^2+0.187Mg^2+0.187Mg^2+0.063)0.959Fe^+1.182[(Si4.997 Al0.003)5.0^O14.768(OH) 0 232 ]. The crystal structure of the babingtonite is determined from X-ray powder diffraction data by Ri-etveld method. The space group is confirmed to be P1 with unit cell parameters :α=0. 746 6 ( 1 )nm, b = 1. 163 1(2)nm, c=0.6684(1) nm, α=91. 554(4)°,β= 93. 889 (3) °and y = 104. 193 (3)°. The Rietveld refineof babingtonite crystal,two silica-oxygen tetrahedron single chains extend along [ ! 10 ] , and connected with dis- torted iron-oxygen octahedron and distorted calcium-oxygen dodecahedron.
出处
《桂林理工大学学报》
CAS
北大核心
2011年第2期177-184,共8页
Journal of Guilin University of Technology
基金
国家自然科学基金项目(40572026)
广西教育厅科研项目(201010LX182)