SYNTHESIS OF SOME CRYSTALLOCHEMICAL ANALOGS STRONTIUM ANORTITE AND THEIR INTERRELATIONS. Arifov P.A. Inst. of Chemistry, Tashkent, Uzbekistan.
The results of syntesis and investigation of some strontium anortite varieties and their analogs interrelations are given. SrAl2Si2O8 and SrAl2Ge2O8 triclinnic forms were obtained by solid phase reactions, differently from the former, SrAl2Ge2O8 was obtained close to the melting temperature. Anortite hexagonal and orthorombic forms and their analogs were obtained by glass or melt crystallization. SrAl2Si2O8 a=8,21; b=12,84; d=3120 kg/m3 tricl. SrAl2Ge2O8 a=8,562; b=13,27; c=7,28; d=3740 kg/m3 tricl. The synthesis temperature of SrAl2Si2O8 corresponds to 1500o C and for SrAl2Ge2O8 - 1450oC, the melting temperature is respectivety 1710 and 1515oC. Also, studed the interrelations of hexagonal varieted of solid solution in the system SrAl2Si2O8 - BaAl2Si2O8 (Table).
Compound Dens Prms elem. Ind/refr.
cell,
A
kg/m3 a c V, A3 Ng Np
SrAl2Si2O8 2980 5,25 7,56 180 1,573 1,57
1
Sr0,9Ba0,1Al2 3010 5,25 7,58 181 1,573 1,57
Si2O8 1
Sr0,7Ba0,3Al2 3080 5,25 7,64 182 1,573 -
Si2O8
Sr0,5Ba0,5Al2 3150 5,25 7,68 183 1,573 -
Si2O8
Sr0,3Ba0,7Al2 3220 5,25 7,74 184 1,573 -
Si2O8
Sr0,1Ba0,9Al2 3300 5,25 7,76 185 1,573 -
Si2O8
BaAl2Si2O8 3320 5,25 7,82 186 1,573 -
The crystallochemical similarities in the homological series system of SrGa2Si2O8 - SrGa2Ge2O8 have also been studied.