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High-temperature heat capacity of Co3O4 spinel: thermally induced spin unpairing transition

K. Mocala·A. Navrotsky·David M. Sherman
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Abstract

A strong anomaly was found in the heat capacity of Co3O4 between 1000 K and the decomposition temperature. This anomaly is not related to the decomposition of Co3O4 to CoO. The measured entropy of transition, ??S=46??4 J mol-1 K-1 of Co3O4, supports the interpretation that this anomaly reflects a spin unpairing transition in octahedrally coordinated Co3+ cations. Experimental values of heat capacity, heat content and entropy of Co3O4 in the high temperature region are provided. The enthalpy of the spin unpairing transition is 53??4 kJ mol-1 of Co3O4. ?? 1992 Springer-Verlag.

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K. Mocala, A. Navrotsky, David M. Sherman. 1992. High-temperature heat capacity of Co3O4 spinel: thermally induced spin unpairing transition. https://doi.org/10.1007/bf00198606

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