Hydrothermal Synthesis of Some Varieties of Zircon

Autor: Izumi Nakai, Tetsuo Shima, Mihoko Izawa, Kozo Nagashima
Rok vydání: 1976
Předmět:
Zdroj: Bulletin of the Chemical Society of Japan. 49:3548-3551
ISSN: 1348-0634
0009-2673
DOI: 10.1246/bcsj.49.3548
Popis: Some varieties of zircon which contain yttrium, niobium, and phosphorus in solid solution have been synthesized at temperatures 500–550 °C and under pressures 700–1000 kg/cm2. In zircon containing yttrium, the unit cell constants a and c increase with increase in yttrium content up to 70 mol%. From IR and TGA studies, a valence compensation accompanying the substitution of yttrium is assumed to be effected by a concomitant substitution of OH for O sites, and the variety is represented by a formula (Zr,Y)Si(O,OH)4. On the other hand, the substitution of Nb5+ for Zr4+ is followed by a decrease in the cell constants. Zircon phase did not form from starting materials with more than 20 mol% of niobium content. From the syntheses of zircon containing both yttrium and niobium, the formula (Zr,Y,Nb) Si(O,OH)4 is found to be appropriate for naegite. An attempt was made to synthesize some solid solutions between zircon and xenotime. The unit cell constant c of the products is found to decrease with the substitution...
Databáze: OpenAIRE