Orthosilicates with glaserite-type crystal structures: NaBaZr[SiO] and NaBaHf[SiO].

Single crystal particles of NaBaZr[SiO] [systematic name: disodium barium zirconium bis-(orthosilicate)] and NaBaHf[SiO] [disodium barium hafnium bis-(orthosilicate)] were extracted from grain-grown polycrystals obtained by heating compacts of binary oxide mixtures at 1473 K. Single crystal X-ray diffraction analysis revealed that these are isostructural orthosilicates with a glaserite-type crystal structure, in which all sites of , , , and in the general formula [(O)] are fully occupied by atoms of different elements. The crystal structures of the title compounds were refined in space group 3 under consideration of a two-component twin model. The SiO tetra-hedra are rotated approximately ±10.2° from the mirror plane of space group 3 around an axis parallel to [001].