Heat capacities and thermodynamic functions of CdNb2O6 and CdTa2O6

The molar heat capacity parameters of CdNb2O6 and CdTa2O6 oxides, which attracted attention for their promising catalytic and optical properties, were measured between 323 and 1273 K by DSC (differential scanning calorimeter). Heat capacities and thermodynamic functions such as enthalpy increments (HT∘-H298.15∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$H_{{\text{T}}}^{ \circ } - H_{{{298}{\text{.15}}}}^{ \circ }$$\end{document}), entropies (ST∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$S_{{\text{T}}}^{ \circ }$$\end{document}), Gibbs energy functions—(GT∘-H298.15∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$G_{{\text{T}}}^{ \circ } - H_{{{298}{\text{.15}}}}^{ \circ }$$\end{document}) T−1 were computed for the temperature range of 298.15–1273 K. The Cp.m∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C_{{{\text{p}}.{\text{m}}}}^{ \circ }$$\end{document} (298.15) values of CdNb2O6 and CdTa2O6 oxides were computed as 176.111 J K−1 mol−1 and 179.650 J K−1 mol−1, respectively. The fit heat capacities of the oxides showed good agreement with Neumann–Kopp rule (NKR), both at room temperature (Cp.m∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C_{{{\text{p}}.{\text{m}}}}^{ \circ }$$\end{document} (298.15)) and the corresponding temperature increase (Cp.m∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C_{{{\text{p}}.{\text{m}}}}^{ \circ }$$\end{document} (T)) in the range of 298.5–1000 K.