Etude cristallographique du systeme ternaire LiVWO6-WO3-LiV12W32O6 á 700°C》.pdf

J. inorg,nucl.Chem.,197LVol.33,pp.2403to 2418. P¢qlamonPress. PrintedinGreatBritain E T U D E C R I S T A L L O G R A P H I Q U E D U S Y S T E M E T E R N A I R E LiVWOe-WO3-LiVl/2Wa/2Oe A 700°C JEAN GALY, GEORGES MEUNIER, JEAN SENEGAS et PAUL H A G E N M U L L E R Service de Chimie Min6rale Structurale de la Facult6 des Sciences de Bordeaux associ6 ou C.N.R.S., 351 Cours de la Lib6ration, 33 Talence, France (First received 15January 1969; in revisedform 5 July 1970) R(~mn~-L6tude du syst~me ternaire obtenu h partir de la phase LiVWOe par les substitutions V 5++ Li + = W 6++ [] et 2V 5+ = W e++ V + a permis de d61imiter h 700°C les domaines dhomog6n6it6 de deux phases, lune de type brann6rite, Iautre de type columbite. Une 6tude structurale complete montre que les atomes de vanadium et de tungst~ne sont distribu6s de mani~re d6sordonn6e dans les sites cristallographiques, saul pour une composition voisine de LiVll2Wsl=Oe,pour laqueUe a 6t6 mis en 6vidence un ordre cristaUographique. Les auteurs montrent la filiation structurale entre les phases PbO~, columbite et LiVlj2W312Os. Al~tract-The study of the ternary system obtained from LiVWO6 phase by the substitutions V 5++ Li+ = W 6++ [] and 2V ~+ = We++ V4÷ has allowed to delimit at 700C the homogeneity ranges of two phases, one of the brannerite type, the other of the columbite type. A complete structural study shows a disordered distribution for the vanadium and tungsten atoms in the crystallographic sites except for a random composition of LiV11~W312Oewhere a crystallographic order has been determined. The authors show the structural filiation between the PbO2t~, columbite and LiV~z~W3~206phases.