title: High-Pressure Framework Silicates
abstract: Recent syntheses of high-pressure alkali and alkaline earth silicates reveal a class of framework structures with corner-linked 4- and 6-coordinated silicon. These compounds possess the structural formula (A4-2x1+Bx2+)SimVI(SinIVO2(m+n)+2), where x, m, and n specify the amounts of alkaline earth, 6-coordinated silicon, and 4-coordinated silicon, respectively. Appropriate values of m and n yield a range of high-pressure structures, from fully 4-coordinated to fully 6-coordinated silicate frameworks. Recognition of this class of framework silicates leads to predictions of high-pressure structures as well as room-pressure isomorphs of high-pressure silicates.
authors.affiliation: Geophysical Laboratory and Center for High Pressure Research, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015-1305, USA.
authors.initials: RM
authors.lastname: Hazen
authors.initials: RT
authors.lastname: Downs
authors.initials: LW
authors.lastname: Finger