单斜星叶石矿物的穆斯堡尔光谱学研究

Mssbauer spectroscopic study of monoclinic astrophyllite.

本文对产于俄罗斯希宾地区的单斜星叶石进行了不同的温度条件下的穆斯堡尔光谱效应研究,通过在温度分别在298 K,180 K和80 K条件下的分析,发现单斜星叶石由2个Fe^(2+)和1个Fe^(3+)四极双峰组成,并进行了单斜星叶石中的畸变参数包括八面体键角(σ~2)和键长变量(Δ)的计算。但是,在两个畸变参数之间存在着明显的差异,将无法对它们的穆斯堡尔参数和四极双峰进行指派。本文对温度在同质异能位移和四极分裂中的作用进行了探讨,根据通过穆斯堡尔效应和f(Fe^(3+)(O))/f(Fe^(2+)(O))的平均值获得的三价铁对全铁的比值,改写了单斜星叶石的化学式。

Monoclinic astrophyllite from Kala Peninsula, Russia was investigated by 57Fe MSssbauer effect. The MSssbauer spectra of the sample at 298 K, 180 K and 80 K were measured. Each spectrum of monoclinic astrophyllite consists of two Fe2＋ and one Fe3＋ quadrupole doublets. The distortion parameters, the variances of the octahedral bond angles σ2 and the normalized bond-length variation A for monoclinic astrophyllite were calculated. However, since a discrepancy between two distortion parameters exists, an assignment of the quadrupole doublet to iron at the specific site was not given. Temperature dependences of the isomer shift and the quadrupole splitting were presented and discussed. According to the ratio of ferric to total iron obtained by the Mtissbauer effect and the mean value off （ Fe3＋ （O） ）/f （ Fe2＋ （O） ） , the chemical formula of monoclinic astrophyllite was rewritten.