阳离子替换磷灰石固溶体的比晶体化学

利用XTD,IR对不同阳离子替换的磷灰石(Ap)固溶体进行了比较晶体化学研究，结果表明：端元二价阳离子对Ap晶格常数(a0,c0)影响是线性的，符合Vegard规律，有较好的x-V习性，可作为阳离子半径测定的"结构尺";对于Cl-PO4体系的Ap，端元离子半径须在0.095～0.134nm之间才能形成空间群为P63/m的Ap结构；异价固溶体可以研究Ca(1)、Ca(2)位置的结晶化学差异,Ca(2)位在晶核形成期生成且决定了晶胞的框架，而Ca(1)位主要影响Co；随阳离子半径增加，PO4]四面体的ν4,ν3,ν1红外振动峰向低频方向红移；Ap结构中发现"铅异常"，形成原因是铅在Ca(2)位的较大电负性。

Comparative crystal chemistry on aptite solid solution with cation substitution

Comparative crystal chemistry on apatite (Ap) solid solutions with cations substitution has been investigated by XRD and IR. The results indicated that a0 and co parameters of the Ap with extreme divalent cations increased linearly with substitution rate x and obeyed the Vegrad rule, the x-V behavior could be used as a "structure ruler" for determining cation radii. In the systems of Cl-PO4--Ap, space group P63/m was only consitituted by the cations of the radii between 0.095 nm and 0.134 nm. The crystal chemistry diffrence of Ca(2) site and Ca (1) site might be investigated in the systems of different valent solid solutions. Ca(2) site grew in crystal-core stage and contolled the crystal- cell framework but Ca(1) site mainly affected co; The IR vibational bands (ν4,ν3,ν1 modes) of PO4] tetrahedron varied from high wavenumbers to low wavenumbers with the inrease in the radius of the cation; The reason for formation of "lead-anomaly" found in Ap structure was the large electronegativity of lead in Ca(2) site.