新矿物——罗布莎矿的晶体结构精修

RIETVELD STRUCTURE REFINEMENT OF NEW MINERAL LUOBUSAITE(β-FeSi_2)

利用微量衍射方法得到的粉晶衍射数据和Rietveld全谱拟合方法精修了合金新矿物罗布莎矿(β-FeSi2)的晶体结构,新矿物计算理论分子式为Fe0.83Si2.00,属斜方晶系,空间群为Cmca,a=0.98362 nm,b=0.78301 nm,c=0.78655 nm,z=16。结构精修发现Fe有明显的占位不足,并且这种不足只表现在Fe2位置上,结构中Fe2有明显的空位缺席构造特征。

Luobusaite（β-FeSi2 ）（IMA2005-052a）is a nature Si-Fe alloy new mineral with formula Fe0.83 Si2.00. The crystal structure was refined by the Rietveld method in space group Cmcα,α=0.983 62 nm,b= 0.783 01 nm,c=0.786 55 nm,z=16,by using powder diffraction data obtained by a combination of CCD rotation patterns. The occupancy refinement showed that there was a lack of Fe,and it only occurred at Fe2 site.