A new heterometallic complex {[Cu(pic)2(H2O)2][Cd2(Hdipic)2(H2O)2Cl2]}n (Mr = 1007.73) has been synthesized under hydrothermal condition and characterized by single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 5.8397(4), b = 9.8664(7), c = 14.1739(10) , α = 82.0150(10), β = 80.4540(10), γ = 82.3570(10)o, Z = 1, V = 792.47(10) 3, Dc = 2.112 g/cm3, μ(MoKα) = 2.247 mm-1, F(000) = 495, the final R = 0.0232 and wR = 0.0644 for 2748 observed reflections (I > 2σ(I)). In the complex, seven-coordinated Cd ions form a zigzag chain based on the alternated dinuclear Cd units. The neutral [Cu(pic)2(H2O)2] units are located at the centers of the inter space and fasten to the 1-D chain by hydrogen bonds.
BaCe0.45Zr0.45M0.1O3–δ (M=Y, In) and BaCe0.9Y0.1O3–δ were prepared through the conventional solid state reaction route. The chemical stability was investigated in hydrogen, carbon dioxide, and boiling water. Crystalline phase and microstructure of the proton conductor before and after stability test were measured with X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results showed that all materials were quite stable in H2 atmosphere. In CO2 atmosphere, BaCe0.45Zr0.45M0.1O3–δ (M=Y, In) were rela- tively stable, while BaCe0.9Y0.1O3–δ decomposed. In boiling water, BaCe0.9Y0.1O3–δ was quickly decomposed into Ba(OH)2 and corresponding oxide. BaCe0.45Zr0.45M0.1O3–δ slightly reacted with boiling water and some amorphous phases were formed. However, BaCe0.45Zr0.45In0.1O3–δ was observed to exhibit better stability than BaCe0.45Zr0.45Y0.1O3–δ in water. The experimental results were interpreted in terms of thermodynamic data and tolerance factor.
The standard Gibbs free energy of formation of magnesium ferrite was determined by means of two types of solid state electrochemical cells: one using MgZr4(PO4)6 (MZP) as the solid electrolyte and the other using CaF2 as the solid electrolyte. The first cell was operated in the range of 950 to 1100 K. The second cell was operated in the range of 1125 to 1200 K. The reversibility of the cell EMFs was confirmed by microcoulometric titration. The Gibbs energy changes of magnesium ferrite relative to component oxides were calculated based on EMF measurements and are given by following expressions, respectively: △G I = -3579-15 T (J/mol) and △G II =6258-24.3 T (J/mol). The results obtained from two different cells are consistent with each other. The results also are in agreement with Rao’s and Tretjakov’s data in the measured temperature range. When the Gibbs free energies of formation of MgO and Fe2O3 were substituted in the reaction, the Gibbs free energies of formation of MgFe2O4 was obtained in two temperature ranges and the formations are shown as follows: △G I Formation = -1427394+360.5 T (J/mol) and △G II Formation = -1417557+351.2 T (J/mol).
