High-pressure region of the silica isotypes

Effect of Pressure and Temperature on the Reversal Transitions of Stishovite

“…A study of the effect of temperature on natural stishovite was also made a-f3 quartz boundary by Yoder (1950). Quartz-Coesite boundary (lower temperature) by Dachille and Roy (1959a) and the other by Boyd and England (1960). Coesite-stishovite boundary (lower temperature) by Ostrovsky (1966) and the other by Stishov and Popova (1963).…”

Surface Chemistry and Catalytic Properties of Boron Phosphate: 1. Surface Area and Acidity

“…Gerrard and Griffey (4) discussed a novel preparation of boron phosphate from triethyl phosphate and boron trichloride. A number of papers (5,6,7) have been concerned with high-pressure forms of boron phosphate. V. F. Ross and co-workers (8) prepared boron phosphate for their n.m.r.…”

Synthesis and properties of a high-pressure rutile-type AlAsO4

“…The ratio for the A1AS0 4 polymorphs is 1.51 and the ratio for the Si0 2 polymorphs is 1.49 (SCLAR et al, 1962). The mean of the three published values for the GeO a polymorphs, which range from 1.48 to 1.54, is 1.51 (LIPPIN- COTT et al, 1958;DACHILLE andROY, 1959, andSCLAR et al, 1962). The effect of coordination on the force constant, therefore, is apparently independent of the chemical composition.…”

“…Rutile structure was dominant at about 0.40. DACHILLE and ROY (1959A) suggested that some AB0 4 compounds, not normally rutile, with radius ratios close to 0.40 might be converted to the rutile structure at high pressure. The recent conversion of Si0 2 to the rutile structure at about 120 kbar and 1200C (STISHOV and BELOV, 1962) furnished some experimental basis for the possibility that some AB0 4 compounds, which normally have the quartz structure, might also be converted to the rutile structure at sufficiently high pressure and temperature.…”