Open AccessTetragermanates of strontium, lead, and barium of formula type AB4O9
Author(s) -
Carl R. Robbins,
Eenest M. Levin
Publication year - 1961
Publication title -
journal of research of the national bureau of standards. section a. physics and chemistry
Language(s) - English
Resource type - Journals
eISSN - 2376-5704
pISSN - 0022-4332
DOI - 10.6028/jres.065a.016
Subject(s) - isostructural , barium , strontium , metastability , melting point , crystallography , congruent melting , germanium , materials science , silicate , atmospheric temperature range , diffraction , chemistry , mineralogy , crystal structure , silicon , physics , phase (matter) , thermodynamics , metallurgy , phase diagram , optics , organic chemistry , composite material
Three new tetragermanates, SrGe 4 O 9 , PbGe 4 O 9 , and BaGe 4 O 9 , of formula type AB 4 O 9 were found. BaTiGe 3 O 9 , the germanium analog of the mineral silicate benitoite (BaTiSi 3 O 9 ) was prepared for study and comparison. Indexed X-ray powder diffraction patterns of the tetragermanates and of BaTiGe 3 O 9 and BaTiSi 3 O 9 show: (1) the tetragermanates are apparently isostructural; (2) the unit cell of BaTiGe 3 O 9 at room temperature is related to that of the tetragermanates by a doubling of the c -axis of the latter; (3) the tetragermanates and the metastable (room temperature) form of BaTiGe 3 O 9 are apparently structurally similar to, but not isostructural with benitoite; (4) within its temperature stability range, BaTiGe 3 O 9 appears to be isostructural with BaTiSi 3 O 9 . Density, melting point, and partial optical data for the tetragermanates were obtained.