Abstract

Evaluation of thermo dynamical parameters of synthesized triheteropolymolybdate containing Zn2+ and Cu2+ cations

Author(s): Uma Shankar Upadhyay, Alok Kr.Thakur, Rajesh Kr., R.R.Jha,S.Misra, Nalin Kant Roy

The triheteropolyoxomolybdate containing Zn2+ and Cu2+ cations was synthesised in the dilute acid medium adjusting pH of the solution 4.5 at reflux temperature. The thermal stability analysis of the product was performed and it was observed that the complex involve one step decomposition according to TGA graph producing about 9.01% weight loss which was also duly supported by DTA graph indicating one large exothermic peak maxima a 334.060 C. The thermo dynamical parameters evaluation of thermal decomposition reaction of complex suggests the transaction at high temperature indicating the phase transition with a change in entropy of the system. This type of phase transition at high temperature is attributed as discontinuous change accompanied by the release of heat energy. The product recovered was light bluish-green in appearance. The magnetic moment value at room temperature indicate the six co-ordinate distorted octahedral around Cu (II) environmental in the weak field. The IR spectrum of the isolated product indicates the presence of NH4 +, Mo=O, Mo-O-Mo, Hydrogen bonded H2O group, Zn-O and Cu-O. On the basis of analytical, I.R. spectral, thermal stability and thermo dynamical parameters determination the composition of the product is assigned as (NH4)2 [ZnCuMo5O18]2.14H2O.