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High‐Pressure‐High‐Temperature Polymorphism of the Oxides of Lead
Author(s) -
WHITE W. B.,
DACHILLE FRANK,
ROY RUSTUM
Publication year - 1961
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.1151-2916.1961.tb13739.x
Subject(s) - disproportionation , chemistry , mole , analytical chemistry (journal) , lead oxide , mole fraction , high pressure , rutile , materials science , mineralogy , thermodynamics , chromatography , organic chemistry , physics , catalysis
The common oxides of lead, PbO, PbO 2 , and Pb 3 O 4 , were examined at pressures of 0 to 60,000 atmospheres and temperatures of 100° to 600° C. The pressure‐temperature curve for the litharge‐massicot transition was measured, giving a ΔH of transition of 57 cal. per mole. Unusual meta‐stability and inversion characteristics of the massicot phase were examined in detail. PbO 2 (rutile) transformed at pressures in excess of 13,000 atmospheres at 300°C. to an ortho‐rhombic form. The univariant equilibrium curve for the transition gave a Δ H of 11 cal. per mole. Pb 3 O 4 underwent a disproportionation reaction yielding PbO and “Pb 2 O 3 .” The equilibrium curve for this reaction was measured, and Δ H was determined to be 4500 cal. per mole.