Synthesis, Crystal Structure and Thermal Decomposition of [HGdP₂O₇ · 2 H₂O] · NH₃ Electric properties of HGdP₂O₇ and Gd₂P₄O₁₃

<p>A new gadolinium diphosphate [HGdP₂O₇ · 2 H₂O] · NH₃ was synthesized <i>via</i> 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.</p> <p>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.</p> <p>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.</p