Thermal decomposition mechanism, thermodynamical and quantum chemical of properties [Pb(NTO)(2)(H2O)]

The single crystal of lead salt of 3-nitro-1,2,4-triazol-5-one (NTO), [Pb(N TO)(2).(H2O)] was prepared and its structure was determined by a four-circl e X-ray diffractometer. The crystal is monoclinic, its space group is P2(1) /n with crystal parameters of a=0.7262(1) nm, b=1.2129(2) nm, c=1.2268(3) n m, beta=90.38(2)degrees, V=1.0806(2) nm(3), Z=4, D-c=2.97 gcm(-)3, +=157.83 cm(-1), F(000)=888. The final R is 0.027. By using SCF-PM3-MO method we ob tained optimized geometry for [Pb(NTO)(2).(H2O)] and particularly positions for hydrogen atoms. Through the analyses of MO levels and bond orders it i s found that Pb atom bond to ligands mainly with its 6p(z) and 6p(y) AOs. T he 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 mechanis m of [Pb(NTO)(2).(H2O)] has been derived. The lattice enthalpy and its latt ice energy were also estimated.