Electronic Structures of Square Planar Coordinated Transition Metal Ions in Compounds with Gillespite Structure

Electronic structures of square planar coordinated transition metal ions in BaCuSi₄O₁₀ and CaCrSi₄O₁₀ are investigated using the ligand-field theory (LFT), angular overlap model (AOM) and iterative extended Hückel molecular orbital theory (IET). The electronic energy levels of the natural mineral dioptase are also investigated, in which the Cu²⁺ ions occupy the sites of pseudo D_4h symmetry. Both LFT and AOM predict that the crystal-field levels of transition metal ions in these compounds follow such an order that E (²B_1g <E(²B_2g <E(²A_1g )<E(²E_g ), and the frequencies of the crystal-field transitions obtained from point charge calculations are in good agreement with those observed. However, the energy-level order cannot be determined unambiguously from the IET calculation because it depends on the values of parameters chosen for the calculation.     

从地洼成矿作用看中国某些优质锰矿的成因与远景

研究发现中国某些优质锰矿,属复成矿床,它们都是地洼成矿作用的产物。福建连城锰矿就是典型实例,类似矿床特别是复成风化锰矿,还见于闽西南-粤东北及湖南。滇东南一些锰矿,例如著名的斗南锰矿与白显锰矿的成因,也可能与地洼成矿作用有一定联系。分析对比了一些优质复成锰矿和一些较贫的复成锰矿的成矿地质条件。从地洼成矿作用可以看出中国某些优质锰矿的成因与远景。提出在中国东南地洼区、南北地洼区南端及云贵地洼区某些地方,寻找优质复成风化锰矿与复成菱锰矿—硫锰矿矿床是较有希望的。     

广西锰矿床的基性火山喷发—沉积成因的研究

广西境内的4个主要含锰层位(上泥盆统榴江组和五指山组、下石炭统大塘阶、下二叠统孤峰组和中三叠统百逢组)中的锰质成份。全部富集在受基底深断裂和盖层同生沉积断裂控制的又有海底基性火山喷出活动的相对较深水的海槽相区(次要)和与其相沟通的靠近碳酸酸盐台地一侧的台沟相带(主要)中(图1、2、3)。锰矿层、硅质岩、硅质灰岩及基中酸性火山一次火山岩类。无论在时空上还是在成因上都有密切的联系。     

福建省连城锰矿四号矿点锰矿床成因探讨

本文从区域地质、矿床地质特征和矿床的碳、氧、硫同位素组成三方面,论述连城锰矿四号矿点锰矿床的成因,认为矿床赋存于断层带倒转向斜内,系沉积变质而成。     

绿砷钡铁石在广西的发现

本文研究了在广西德保铜锡矿床氧带化中发现的绿砷钡铁石,给出了它的物理性质、化学成分和晶胞参数等矿物学数据。