The entropy of zinc chromite (ZnCr_2O_4)

摘要

The low-temperature heat capacity of zinc chromite (ZnCr_2O_4) was measured between 6.5 K and 400 K using adiabatic calorimetry, and some thermochemical functions (CP(t), 5(7), S~o_(298) H_(t)-H_(o) were derived from the results. The standard entropy (S~o_(298) = 128.6 + -0.3 J mol~(-1) K~(-1)) for zinc chromite was calculated from the results. Our calorimetric measurements indicate one extremely large anomaly in the heat capacity curve at approx 12.3 K which is related to the cubic-tetragonal transition in ZnCr_2O_4.