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Title: Energetics of stable and metastable low-temperature iron oxides and oxyhydroxides

Journal Article · · Geochimica et Cosmochimica Acta
;  [1]
  1. Univ. of California, Davis, CA (United States). Dept. of Chemical Engineering and Materials Science

The energetics of a set of synthetic iron oxides and oxyhydroxides were determined by transposed temperature drop calorimetry and high temperature solution calorimetry using sodium molybdate as a solvent at 979 K. The experiments allow the calculation of the enthalpy of formation from the elements of {gamma}-Fe{sub 2}O{sub 3} with tetragonal symmetry (812.7 {+-} 2.6 kJ/mol) and with cubic symmetry ({minus}812.3 {+-} 2.5 kJ/mol) and {beta}-FeOOH (557.6 {+-} 2.4 kJ/mol), values currently unavailable in the literature. Maghemite, {gamma}-Fe{sub 2}O{sub 3}, is 15.3 {+-} 0.9 kJ/mol less stable in enthalpy than hematite, {alpha}-Fe{sub 2}O{sub 3}.

OSTI ID:
329209
Journal Information:
Geochimica et Cosmochimica Acta, Vol. 62, Issue 17; Other Information: PBD: Sep 1998
Country of Publication:
United States
Language:
English