Studies in oxide chemistry
I 31/1/1799 Studies in oxide chemistry. Cervantes-Lee F.J.The effects caused by simultaneous substitution of the pair of oxides (Na 20, Si02) and (Na 20, Fe203) on tricalcium aluminate have been studied. Neither Si02 nor Fe203 seem to increase the amount of Na20 going into solid solution or prevent the structural changes caused by the limited substitution of Ca by Na atoms in the cubic lattice of pure Ca3A'206 but they have a stabilizing effect on a "pseudo-tetragonal" form of Ca3Al206 solid solution whose true symmetry is now established here as orthorhombic with possible space group P.c a a. A review of the powder diffraction data available for sodium containing Ca3A1206 solid suolutions has been made and new data contributed.Crystallographic data and indexed powder diffraction patterns are presented for two potassium barium silicates, two sodium strontium silicates and a metastable sodium titanate.The crystal structure of k2Be7Si16040 has been solved from three dimensional single-crystal x-ray diffraction data. k2Ba7Si16040 is0monoclinic, space group C2/m, with a - 31.991, b - 7.704, c 8.255 A,3 100.600 and Z - 2. The structure consists of infinite Si205 sheets linked through Be and k atoms.Compound formation and subsolidus equilibria have been studied in the system Na2O _Y203 -S'02' Six ternary phases have been found. Three of these had not been previously reported. Powder diffraction data for their characterization is given. Preliminary data for the liquidus' surface in the system Soda Yttria silica are also reported.