Intermediate products in solid‐state reactions of gadolinium oxide and ammonium dihydrogen phosphate

The solid‐state reactions of Gd₂O₃ with NH₄H₂PO₄ using various molar ratios (3:6, 2:8, 1:6 and 1:8) of the reactants were investigated at different temperatures (350‐1100°C) to observe the intermediate compounds. Analysis of the X‐ray powder diffraction patterns of the products obtained at 350°C; for the compositions of 2:8, 1:6 and 1:8 molar ratios revealed the formation of a new compound, NH₄GdHP₃O₁₀ which was reported previously for Nd, Ho and Er. At higher temperatures, gadolinium tripolyphosphate was obtained for all of the molar ratios. On the other hand, the IR data of the products also confirmed the proposed reaction pathways. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)