Beiträge zur Kristallchemie und zum thermischen Verhalten von wasserfreien Phosphaten. XXXVI [1] Synthese, Kristallstruktur und spektroskopische Charakterisierung von Palladium(II)‐diphosphat Pd 2 P 2 O 7

Synthesis, Crystal Structure and Spectroscopical Characterization of Palladium(II)‐Diphosphate Pd 2 P 2 O 7 Pd 2 P 2 O 7 is synthesized by heating (T max = 500 °C) stoichiometric amounts of PdO and phosphoric acid. Using chemical vapour transport experiments (850 °C → 750 °C, addition of PdCl 2 ) Pd 2 P 2 O 7 was crystallized. Pd 2 P 2 O 7 adopts its own structure type (C 2/c (No. 15), Z = 4, a = 13,151(2) Å, b = 5,172(1) Å, c = 8,139(1) Å, β = 97,52(1)°, 1160 independent reflections, 55 variables, R1 = 0,021 and wR2 = 0,050). Square‐planar [PdO 4 ]‐units $({\bar d}\rm (Pd-O)=2,020 \AA)$ are linked by diphosphate‐groups generating a 3D framework. Within this framework ribbons $^{1}_{\infty}\rm[Pd(P_{2}O_{7})]^{2-}$ may be distinguished. Thus Pd 2 P 2 O 7 might be described as palladium(II)‐[diphosphatopalladate(II)]. The results of various spectroscopic measurements (IR, Raman, UV/VIS, 31 P‐MAS‐NMR) are reported and discussed within the context of the crystal structure.