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Stability of the Aluminum Silicates
Author(s) -
FLOOD H.,
KNAPP W. J.
Publication year - 1957
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.1151-2916.1957.tb12604.x
Subject(s) - kyanite , andalusite , sillimanite , silicate , ionic bonding , mineralogy , ternary operation , phase diagram , phase (matter) , aluminium , chemistry , silicate minerals , materials science , thermodynamics , inorganic chemistry , geology , metamorphic rock , metallurgy , geochemistry , ion , quartz , physics , organic chemistry , biotite , computer science , programming language
From the ternary phase diagrams of Al 2 O 3 –SiO 2 with CaO, MgO, or FeO, it can be concluded that the free energies of formation of kyanite, andalusite, and sillimanite, according to the reaction Al 2 O 3 + SiO 2 = Al 2 O 3 .SiO 2 , are of the order of magnitude of 0 to –10 kcal. rather than the previously accepted value of –40 to –45 kcal. However, this result may be expected from the general variation of free energies of formation with the ionic potential of the silicate‐forming cation; this conclusion is supported by a plot for some silicates, carbonates, and sulfates.