中国坡缕石晶体化学研究  

CRYSTAL CHEMISTRY OF PALYGORSKITE IN CHINA

作　　者：郑自立[1] 田煦[2] 蔡克勤 王濮 A.McDonald R.Whitehead 

机构地区：[1]中南工业大学地质系,长沙410073 [2]中南地质大学,北京100083 [3]DepartmentofGeology,LaurentainUniversity,SudberyOntarioCanada,P3E2C6

出　　处：《矿物学报》1997年第2期107-114,共8页Acta Mineralogica Sinica

摘　　要：本研究通过对坡缕石化学成分分析数据的系统数理统计分析及结合透射电镜研究提出了Al2O3、Fe2O3、Mgo同SiO2一样为坡缕石的自身氧化物组分，而CaO、K2O、Na2O、TiO2等为主要以吸附态存在的非自身氧化物成分。相应的坡缕石晶体化学式为（Mg、Al、Fe、）5SiO20。（OH）2：·4（H2O）·nH2O（□—空位）。Ala3+、Fe3+、Mg2+异价类质同象置换的线性方程为Mg2+=4．978－1．519（Al3+＋Fe3+）。穆斯堡尔谱、红外光谱及（020）面网晶格条纹象的分裂研究表明了阳离子占位形式：MIM2M3M3M1，其中边缘M1=（Fex3＋）（Mg），中间M3=（A13+＋Fe3＋），M2=Al3+（缺Fe3+）或M2=（Fe3+＋Al3+）或等于（Fe3+）和（□）。坡缕石的Mg2+－Al3+－Fe3+组分三角形图解揭示了：富Fe外生沉积成因为主的土状坡缕石和贫Fe富Al的热液交代蚀变充填作用为主的纤维状坡缕石的成分成因分类。Like SiO2, Al2O3, Fe2O3 and MgO are the components of palygorskite itself while CaO,TiO2, K2O and Na2O are the components in the form of adsorbates based on the mathematicalstatistic analysis of 36 chemical composition data of palygorskites from various locations in China.The crystal chemical formula of palygorskite is (Mg, Al, Fe, )5Si8O20 (OH)2. 4 (H2O). nH2O,and the linear relation of cations in the octahedral zone is Mg2+ = 4. 978~1. 519 (Al3+ +Fe3+ ), thenl. l4＜Al3+ +Fe3+＜2. 5. The Mossbauer spectra, infrared spectra and lattice figure indicate thatthere is only one kind of Fe3+ in palygorskite and the occupancies of cations in the octahedral siteare M2M1M3M1M2, M2 = (Mg.) (Fe1-x), M3 = (Al3+ ) or (Al3+ ＋Fe3+ ), M1 = (Al3+＋Fe3+ ) or Fe3+ and □ (□ is the empty octahedron site). The palygorskites were divided into clayeyor sedimentary palygorskite rich in Fe3+ and derived from sedimentation, and fibrous or hydrother-mal palygorskite poor in Fe3+ and rich in Al3+ and derived from hydrothermal alteration.

关 键 词：坡缕石 晶体化学 穆斯堡尔谱 红外光谱 晶格象 

分 类 号：P578.94[天文地球—矿物学] P573[天文地球—地质学]