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PROPERTIES OF SOME SUBSTANCES ISOSTRUCTURAL WITH SILICA *
Author(s) -
Hummel F. A.
Publication year - 1949
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1949.tb18905.x
Subject(s) - cristobalite , quartz , mineralogy , thermal expansion , materials science , thermal , endothermic process , isostructural , tridymite , chemical engineering , chemistry , crystallography , thermodynamics , crystal structure , composite material , physics , adsorption , engineering
A bstract Quartz and cristobalite types of AlPO 4 were prepared in a pure condition and compared with silica regarding thermal behavior. The thermal expansion of the cristobalite type of AlPO 4 is remarkably similar to that of cristobalite, indicating a close structural relationship at elevated temperatures as well as at room temperature. The temperature of inversion of the cristobalite type of AlPO 4 apparently depends on previous thermal history, as in the case of cristobalite, but the presence of a double endothermic peak during the low‐high inversion may indicate that the mechanism is different from that involved in the low‐high cristobalite transition. Data on the thermal expansion of the network structures NaAlSiO 4 (carnegieite) and Na 2 CaSiO 4 are presented and are discussed in the light of the known structural relationships in the series high cristobalite, high carnegieite, and Na 2 CaSiO 4 .