Authors:J. Song, R. Hu, B. Kang, Y. Lei, F. Li, and K. Yu
[Cd(NTO)4Cd(H2O)6]4H2O was prepared by mixing the aqueous solution of 3-nitro-1,2,4-triazol-5-one and cadmium carbonate in excess. The single crystal
structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, space group C2/c with crystal parameters
of a=2.1229(3) nm, b=0.6261(8) nm, c=2.1165(3) nm, β=90.602(7), V=2.977(6) nm3, Z=4, Dc=2.055 gcm−3, μ=15.45 cm−1, F(000)=1824, λ(MoKα)=0.071073 nm. The final R is 0.0282. Based on the results of thermal analysis, the thermal decomposition mechanism of [Cd(NTO)4Cd(H2O)6]4H2O was derived. From measurements of the enthalpy of solution of [Cd(NTO)4Cd(H2O)6]4H2O in water at 298.15 K, the standard enthalpy of formation, lattice energy, lattice enthalpy and standard enthalpy of dehydration
have been determined as -(1747.84.8), -2394, -2414 and 313.6 kJ mol−1 respectively.
Authors:S. Jirong, C. Zhaxou, Hu Rongzu, X. Heming, and L. Fuping
The single crystal of lead salt of 3-nitro-1,2,4-triazol-5-one (NTO), [Pb(NTO)2(H2O)] was prepared and its structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, its space group is P21/n with crystal parameters of a=0.7262(1) nm, b=1.2129(2) nm, c=1.2268(3) nm, =90.38(2)°, V=1.0806(2) nm3, Z=4, Dc=2.97 g cm–3, µ=157.83cm–1, F(000)=888. The final R is 0.027. By using SCF-PM3-MO method we obtained optimized geometry for [Pb(NTO)2
H2O] and particularly positions for hydrogen atoms. Through the analyses of MO levels and bond orders it is found that Pb atom bond to ligands mainly with its 6pz and 6py AOs. The thermal decomposition experiments are elucidated when [Pb(NTO)2
H2O] is heated, ligand water is dissociated first and NO2 group has priority of leaving. Based on the thermal analysis, the thermal decomposition mechanism of [Pb(NTO)2
H2O] has been derived. The lattice enthalpy and its lattice energy were also estimated.
An earlier published concept, showing correlations between the “average lattice energy” of glasses (i.e. their mean molar atomization enthalpy ΔAH at 298 K), the network dimensionalityD and some properties of different chalcogenide and oxide glasses, was used to interpret the transformation temperaturesTg of glasses containing fluorine or nitrogen instead of oxygen. A plot of Tgvs. ΔAH allows the comparison of completely different glasses from only one graph. Such a consistent evaluation of composition/property relationships is useful for the further improvement of fluoride and nitride glasses, which are important for applications in optics and telecommunications and as quality-limiting components in silicon nitride-based ceramics.
Authors:A. La Ginestra, R. Cerri, F. Giannetta, and P. Fiorucci
Li, Na, K, Rb, Cs and NH4 hexamolybdochromates have been prepared, characterized by X-ray and IR spectra, and their thermal behaviour was studied. We observed that the anion decomposition occurs only when the last 3 H2O are eliminated. TheΔH values for this elimination decrease from the Li to the Cs salt in the same manner as the lattice energies found in other alkali salts with a common anion. The exothermic reactions in the decomposition of the complexes are interpreted by inspection of the compounds obtained.
Authors:Sergei N. Danilchenko, Aleksei N. Kalinkevich, Roman A. Moskalenko, Vladimir N. Kuznetsov, Aleksandr V. Kochenko, Evgenia V. Husak, Vadim V. Starikov, Fuyan Liu, Junhu Meng, and Jinjun Lü
crystal lattice, which depends on the level of imperfection and disorder in the structure of biominerals [ 21 ]. More ordered crystals (e.g., in mature bone) have much smaller latticeenergy than low-mineralized apatites with numerous structural defects
Authors:Farhad Gharagheizi, Mohammad Hossein Keshavarz, and Mehdi Sattari
Gharagheizi , F , Sattari , M , Tirandazi , B . 2011 . Prediction of crystal latticeenergy using enthalpy of sublimation: a group contribution-based model . Ind Eng Chem Res . 50 4 2482 – 2486 10