论文部分内容阅读
菱镁铀矿(Bayleyite)是含水镁铀酰碳酸盐矿物.化学式为 Mg_2(UO_2)(CO_3)_3·18H_2O,单斜晶系,晶胞参数a=6.499(1)A,b=15.235(5)A,c=26.513(6)A,β=92.92(2)°V=2621.65A~3,z=4,空间群P2_1/c.文中首先用Patterson函数导出U参数,随后用Fourier法逐步导出Mg,O,C等非氢原子的坐标参数.用块矩阵最小二乘程序修正,最后的R值为0.043,加权后R_w=0.038. 菱镁铀矿属层状结构,结构单元层由一层铀酰-碳酸根络阴离子组成,镁阳离子分布在层间.Mg~(2+)周围以六个水分子配位形成八面体,Mg—O为 2.024—2.100A.结构层内和层间都是由分布在其间的水分子形成的氢键相连接。
Bayleyite is a hydrous magnesium uranyl carbonate mineral with the chemical formula of Mg 2 (UO 2) (CO 3) 3 · 18H 2 O, monoclinic system with unit cell parameters a = 6.499 (1) A and b = 15.235 5) A, c = 26.513 (6) A, β = 92.92 (2) ° V = 2621.65A ~ 3, z = 4, space group P2_1 / c. In this paper, the Patterson function is first used to derive U parameters, The coordinate parameters of Mg, O, C and other non-hydrogen atoms are deduced.The block matrix least-squares procedure is used to correct the final R value of 0.043 and the weighted R_w = 0.038.The magnesite uranium ore belongs to the layered structure and the structural unit layer consists of one Layer uranyl-carbonate complex anions, magnesium cations are distributed between the layers, the octahedron is coordinated by six water molecules around Mg 2+, and the Mg-O is 2.024-2.100 A. The intra- and inter- Are all connected by hydrogen bonds formed by water molecules distributed in between.