Enthalpy, heat capacity and enthalpy of transformation of Li2TiO3

The enthalpy of β- and γ-Li2TiO3 (Li/Ti=1.88) was measured between 397 and 1650 K by isothermal drop calorimetry. The smoothed enthalpy curve between 298 and 1700 K results in H°(T)−H°(298 K)=−49181+131.876T+0.011097T2+2651112T−1 J/mol (298–1410 K) and H°(T)−H°(298 K)=+49729+50.517T+0.031679T2−20 143 786T−1J/mol (1410–1700 K). The heat capacity was derived by differentiation of the enthalpy curve. The value extrapolated to 298 K is Cp,298=(108.6±2.5) J/K mol. The enthalpy of the monoclinic–cubic transformation of Li2TiO3 was determined by anisothermal calorimetry and gives ΔtrH=(9200±300) J/mol at about 1410 K.