The molar heat capacities of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ were obtained using the differential scanning calorimetry (DSC) technique in a temperature range from 298 to 1473 K. The DSC curve of La2Mo2O9 showed an endothermal peak around 834 K corresponding to a first-order monoclinic-cubic phase transition, and the enthalpy change accompanying this phase transition is 5.99 kJ/mol. No evident endothermal peak existed in the DSC curve of La1.9Sr0.1Mo2O9-δ, but a broad thermal anomaly existed in its heat capacity curve at around 832 K. In addition, the heat capacity values of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ began to decrease at 1196 and 1330 K, respectively. The non-transitional heat capacity values of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ were formulated using multiple regression analysis in two temperature ranges.
Baijun Yan Jianhua Liu Yunduo Dai Qifeng Shu Zhihua Ren
Sr-doped La2Mo2O9 were prepared by solid state reaction and characterized by XRD,impedance spectroscopy and HebbWagner polarization method.XRD patterns of the samples indicated that the solubility limit of Sr2+ in La2-xSrxMo2O9-δ was in the range of 7 mol.% to 7.5 mol.%,i.e.,the maximum stoichiometric coefficient x in La2-xSrxMo2O9-δ was larger than 0.14 and less than 0.15.The cubic lattice parameter of La2-xSrxMo2O9-δ(0
Single-phase La_(2–x)Nd_xMo_2O_9(0≤x≤1.8) compounds were prepared using solid-state reaction technique. Their structural and thermal p roperties were characterized by room and high temperatures X-ray diffraction(XRD), thermo gravimetric analysis-differential scanningcalorimetry(TG-DSC), and high temperature Raman spectra. The transport properties were investigated using D.C. four-probe technique and Hebb-Wagner polarization method. The substitution limit of Nb^(3+) in La_(2–x)Nd_xMo_2O_9 was determined to be in the range of 1.8
