尼日利亚石类矿物的晶体化学研究及其意义

CRYSTAL CHEMISTRY OF THE MINERALS OF NIGERITE SPECIES AND ITS SIGNAFICANCE

湖南省安化、临武、柿竹园等地区有一类含锡、镁、铁、锌、钛、锰、铝等多种元素的复杂氧化物矿物 ,它们是尼日利亚石、镁尼日利亚石 (彭志忠石 )等。本文从紧密堆积原理出发 ,深入探讨了尼日利亚石类矿物的晶体化学特征。它们的晶体结构可用O(阳离子八面体配位的层 )、T1(阳离子八面体配位与一种方向阳离子四面体配位的混合层 )、T2 (阳离子八面体配位与两种方向阳离子四面体配位的混合层 )堆积方式表征 ,O层与T层交替排列。尼日利亚石 6H的晶体结构表示为…OT2 OT1OT1… ,尼日利亚石 2 4R的晶体结构表示为…OT1OT2 OT2 OT1…× 3 ,等等 ;它们的晶体结构中既有尖晶石的…OT2 OT2 … ,又有铁钒矿的…OT1OT1…晶体结构单位。这类矿物研究在矿物学、宝石学。

There is a type of complex oxide minerals, composed of many elements such as Sn, Mg, Fe, Zn, Ti, Mn, Al, etc., in the areas of Anhua, Linwu, Shizhuyan, and Hunan Province. These minerals are nigerite, Mg nigerite(pengzhizhongite), etc.According to the principle of closest packing, discussed deeply their crystal chemical characteristics of nigerite(brown), pengzhizhongite(buff), Zn nigerite(fawn), Fe nigerite(bottle), Mn nigerite(greenish black) etc. are discussed in detail. Their crystal structures can be characterized with O (expressed as the layers of cation octahedral coordinations), T 1 (express the mixed layers of cation octahedral coordinations and cation tetrahedral coordinations in one direction), and T 2 (expressed as the mixed layers of cation octahedral coordinations and cation tetrahedral coordinations in two directions. The crystal structure of the mineral can be expressed by O, T 1, T 2 packing. O alternates with T. Such as the crystal structure of pengzhizhongite 6H can be expressed by ...OT 2OT 1OT 1...; taaffeite 8 H , ...OT 2OT 1OT 2OT 1...; and nigerite 24R , ...OT 1OT 2OT 2OT 1...×3, etc. In their structures, not only have the crystal structure units of spinel ...OT 2OT 2...; but also have the units of nolanite...OT 1OT 1.... The research of thhese minerals has important theoretic and actual significances in the fields of minneralogy, gemmology, materials science, etc.