Synthesis, Crystal Structure and Thermal Decomposition of [HGdP2O7 · 2 H2O] · NH3 Electric properties of HGdP2O7 and Gd2P4O13
A new gadolinium diphosphate [HGdP2O7 · 2 H2O] · NH3 was synthesized via a soft chemistry route from evaporation of aqueous solution. It crystallizes in the space group Pī with Z = 2 and the following unit cell dimensions: a = 6.4609(2), b = 6.9810(2), c = 9.813(4) Ǻ, α = 81.345(3), β = 80.547(3), γ = 88.430(3)°. IR spectroscopy confirmed the presence of P-OH group, and both ammonia and water molecule in the studied material.
The thermal decomposition of [HGdP2O7 · 2 H2O] · NH3, as investigated by Controlled Rate Thermal Analysis, took place in three stages between -23 and 600 °C leading to the anhydrous salt HGdP2O7. The calcination of the synthesized product at 850 °C in a static air furnace allowed us to obtain the tetraphosphate Gd2P4O13. X-ray powder diffraction and infrared spectroscopy were used to identify these materials.
The electrical properties of HGdP2O7 and Gd2P4O13 were investigated through impedance complex analysis. Modest conductivity has been observed in both materials at relatively medium temperature range. Activation energies of 0.62 and 1.21 eV, were deduced from the Arrhenius plots for HGdP2O7 and Gd2P4O13, respectively.
