含钡硫铝酸钙晶体的合成及其结构和形态

Synthesis,Structure and Morphology of Barium bearing Calcium Aluminosulphate Crystals

以ＣａＣＯ３，Ａｌ２Ｏ３，ＢａＳＯ４和ＣａＳＯ４·２Ｈ２Ｏ为原料，在１３５０℃加热合成Ｃ（４－ｘ）ＢｘＡ３Ｓ粉晶，然后以ＰｂＣｌ２为助熔剂，借助于熔盐法制备了含钡硫铝酸钙单晶，在对其粉晶Ｘ射线多晶衍射谱指标化的基础上，以高纯Ｓｉ作内标测定了Ｃ（４－ｘ）ＢｘＡ３Ｓ（ｘ＝０．２５，０．５，０．７５，１．００）晶体属等轴晶系，立方体心晶格，晶胞参数分别为ａ０＝９．２８０，９．２３３，９．２６１和９．３０３ｎｍ，与其成分变化成直线关系，符合Ｖｅｇａｒｄ定律。电镜观察该晶体外形为菱形十二面体。并分析了该晶体的红外光谱。

The barium bearing calcium aluminosulphate [C (4- x ) B x A 3 ]minerals were synthesized at 1350 ℃ using CaCO 3,Al 2O 3,BaSO 4 and CaSO 4·2H 2O as starting raw materials. C (4- x ) B x A 3 single crystals were obtained by means of flux method with PbCl 2 as the flux.On the basis of indexing of XRD data,the structure of C (4- x ) B x A 3 was determined to be a cubic body center structure.The cell parameters of C (4- x ) B x A 3 ( x =0.25, 0.5, 0.75, 1.00) are a 0= 9.208 nm, 9.233nm, 9.261nm and 9.303nm respectively,which is proportional to the content variation,and accord with Vegard law is valid in this case.The morphology of the crystal is rhombic dodecahedron observed with a SEM.IR spectrum revealed the existence of [AlO 4] tetrahedron in the structure.