Synthesis, crystal structure, and vibrational spectroscopic and UV-visible studies of Cs2MnP2O7

A new member of the A(2)MP(2)O(7) diphosphate family, Cs2MnP2O7, has been synthesized and structurally characterized. The crystal structure was determined by single crystal X-Ray diffraction. Cs2MnP2O7 crystallizes in the orthorhombic system, space group Pnma (#62), with the unit cell parameters a=16.3398(3), b=5.3872(1), c=9.8872(2) angstrom, Z=4 and V=870.33(3) angstrom(3). The structure parameters were refined to a final R-1/wR(2)=0.0194/0.0441 for 1650 observed reflections. The 2D framework of Cs2MnP2O7 structure consists of P2O7 and MnO5 units. The corner-shared MnO5 and P2O7 units are alternately arranged along the b axis to form [(MnO)P2O7]infinity chains. These chains are interconnected by an oxygen atom to form sheets parallel to the (b, c) plane. The cesium atoms are located between the sheets in 9- and 10-fold coordinated sites. The infrared and Raman vibrational spectra have been investigated. A factor group analysis leads to the determination of internal modes of (P2O7) groups. UV-visible spectrum consists of weak bands, between 340 and 700 nm, assigned to the forbidden d-d transitions of Mn2+ ion, and of a strong band around 250 nm, attributed to the O-Mn charge transfer. (C) 2012 Elsevier Inc. All rights reserved.