论文部分内容阅读
本文利用直接法和富利叶合成测定了产于我国四川省三叠系蒸发岩里的多钙钾石膏的晶体结构,结构参数经最小二乘法修正后,R=0.084。结构分析表明,多钙钾石膏属单斜晶系,空间群C2/c,a=17.462(8),b=6.828(2),c=18.219(9),β=113.45(4)°,V=1992(1)~3,Z=4,Dm=2.91,Dx=2.90(3)。三个硫酸根四面体各自的平均S—O键长为1.467、1.464和1.478。有三套Ca原子,其中Ca_1在二次对称轴上。Ca原子的配位数为9,各自的平均Ca—O键长为2.516、2.515和2.459。K原子的配位数为8。首次测定了矿物中氢原子的位置,证实矿物含1个结晶水,而不是含1.5个结晶水。晶体化学式为K_2Ca_5(SO_4)_6·H_2O。
In this paper, the crystal structure of calcium-calcium gypsum produced in Triassic evaporites in Sichuan Province, China, was determined by direct method and Fourier analysis. The structural parameters were corrected by the least square method, R = 0.084. Structural analysis shows that the polycalcium gypsum is a monoclinic with space group C2 / c, a = 17.462 (8), b = 6.828 (2), c = 18.219 (9), β = 113.45 = 1992 (1) ~ 3, Z = 4, Dm = 2.91, Dx = 2.90 (3). Each of the three sulfate tetrahedra each had an average S-O bond length of 1.467, 1.464 and 1.478. There are three sets of Ca atoms, of which Ca_1 is on the secondary axis of symmetry. The coordination number of Ca atoms is 9, and their average Ca-O bond lengths are 2.516, 2.515 and 2.459, respectively. The coordination number of K atom is 8. For the first time, the location of hydrogen atoms in the mineral was determined, confirming that the mineral contains 1 crystal water instead of 1.5 crystal water. Crystal chemical formula K_2Ca_5 (SO_4) _6 · H_2O.