Study on Synthesis and Crystal Structure of Rare-Earth Calcium Silicate

稀土硅酸钙的合成及晶体结构研究

基本信息

批准号：
10450238
负责人：
SHIMADA Masahiko
金额：
$ 8.7万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

In the present study, CaO-Y_2O_3-SiO_2 ternary system was taken up. In this ternary system, apatite-type structure compounds have been reported at the compositions of Ca_2Y_8Si_6O_<26>, Ca_3Y_6Si_6O_<24> and Ca_4Y_6Si_6O_<25>. It was pointed out that the composition of apatite-type compounds had not been established. The preparation of Ca_2Y_2Si_2O_9 having a cuspidine-type structure was carried out, but the crystallographic data has not been reported yet. Generally, silicates have many isomorphs and form many complicated structures. For this reason, new compounds having new structure are expected in this multicomponent system.In CaO-Y_2O_3-SiO_2 ternary system, the compounds prepared by reaction sintering at 1700K were Ca_2Y_8Si_6O_<26> (apatite-type structure), Ca_2Y_2Si_2O_9 (cuspidine-type structure), Ca_3Y_2Si_3O_<12> (silico-carnotite-type structure) and Ca_3Y_2Si_6O_<18> (new structure).A single-phase having an apatite-type structure was prepared at Ca_2Y_8Si_6O_<26>. This phase is hexagonal, a=b=0.9341(1), c=0.6788(1)nm. The sample with the composition of Ca_3Y_6Si_6O_<24> which was reported as apatite-type compound was two phases, Ca_2Y_8Si_6O_<26> and CaSiO_3. The sample prepared at the composition of Ca_4Y_6Si_6O_<25> consisted of Ca_2Y_8Si_6O_<26> and Ca_3Y_2Si_3O_<12>. 1t was confirmed that Ca_2Y_2Si_2O_9 had a cuspidine-type structure (monoclinic P2_l/c, a=0.74468(3), b=1.049240(3), c= 1.09661 (4)nm, β=110.170(3)゜).The new compound, Ca_3Y_2Si_3O_<12> is isostructual with silico-carnotite (Ca_5(PO_4)_2SiO_4). Ca_3Y_2Si_3O_<12> is orthorhombic P nma, a=0.65574(2), b=1.56066(3), c=1.00399(2)nm. Ca_3Y_2Si_6O_<18> (monoclinic C2/c, a=1.33422(5), b=0.77320(3), c=1.47959(6)nm, β=90.263(3)゜) is composed of ternary SiO_4 rings.

在本研究中，CAO-Y_2O_3-SIO_2三元系统被占用。在此三元系统中，已在CA_2Y_8SI_6O_6O_ <26>的组合物中报道了apatite-type结构化合物，CA_3Y_6SI_6O_6O_24>和Ca_4y_6si_6o_6o_ <25>。有人指出，尚未确定磷灰石型化合物的组成。进行了具有cuspidine型结构的CA_2Y_2SI_2O_9的制备，但尚未报告晶体学数据。通常，有机硅具有许多异义，并形成许多复杂的结构。 For this reason, new compounds having new structure are expected in this multicomponent system.In CaO-Y_2O_3-SiO_2 ternary system, the compounds prepared by reaction sintering at 1700K were Ca_2Y_8Si_6O_<26> (apatite-type structure), Ca_2Y_2Si_2O_9 (cuspidine-type structure), CA_3Y_2SI_3O__ <12>（硅 - 肉醇型型结构）和Ca_3y_2si_6O_6O_ <18>（新结构）。一种具有apatite-type结构的单相是在Ca_2y_8si_6o_6o_6o_ <26>上制备的。此阶段是六边形，a = b = 0.9341（1），c = 0.6788（1）nm。据报道为apatite-type化合物的CA_3Y_6SI_6O__6O__6O__6O__6O__6O_6O_6O_6O_6O_6O_6O_6O_6O_6O_6O_6O_6O_6O_6O_6O__6O_ <26>和casio_3的样品。在CA_4Y_6SI_6O__ <25>组成下制备的样品由CA_2Y_8SI_6O__ <26>和CA_3Y_2SI_3O_3O_ <12>组成。 1T证实CA_2Y_2SI_2O_9具有cuspidine型结构（单斜p2_l/c，a = 0.74468（3），b = 1.049240（3），c = 1.09661（1.09661（4）nm，β= 110.170（3）_3 i_______________________i and condoce con-condie con-coundie coundie coundie coundie coundie coundie coundi coundie coundoighoighone and Coundoighoigh。是带有硅氧石的同源结构（Ca_5（PO_4）_2SIO_4）。 CA_3Y_2SI_3O__ <12>是Orthorhombic P NMA，A = 0.65574（2），B = 1.56066（3），C = 1.00399（2）NM。 CA_3Y_2SI_6O__ <18>（单斜骨C2/C，A = 1.33422（5），B = 0.77320（3），C = 1.47959（6）NM，NM，β= 90.263（3））由ternary sio_4 Rings组成。