A New Cadmium-Based Pb2Cd3(PO4)2(P2O7) with Two Types of Isolated P–O Groups

Introduction transition metal with d 10 electrons and lone pair cations with large radius into phosphate systems are helpful to get new crystal structure configuration. Guided by the above method, the first lead cadmium phosphate, Pb 2 Cd 3 (PO 4 ) 2 (P 2 O 7 ), was synthesized. Pb 2 Cd 3 (PO 4 ) 2 (P 2 O 7 ) features a three-dimensional (3D) structure, in which Pb(1) 2 O 8 dimer and Pb(2)O 5 polyhedra are filled between the two-dimensional (2D) layers, which are composed of unique [Cd 6 P 8 O 30 ] groups. In the Pb II M II PO (M II = without or divalent metal ions) systems, the title compound is the first phosphate containing two different P–O groups simultaneously. The ratios of cation/phosphorus (C/P) and polymerization modes of P–O anions have a close relationship by many structural comparisons. Thermal analysis shows that Pb 2 Cd 3 (PO 4 ) 2 (P 2 O 7 ) melts congruently and is thermally stable. In addition, the UV/Vis-IR diffuse reflectance spectrum and infrared (IR) spectrum have been reported. The relationship between electronic structure and optical properties was clarified by first-principles studies. Graphical The crystal structure of a new cadmium-based compound Pb 2 Cd 3 (PO 4 ) 2 (P 2 O 7 ), containing two kinds of P–O groups, exhibits unique [Cd 6 P 8 O 30 ] ∞ layers.