Structure and vibrational spectra of a new trihydrate diphosphate, MnNH₄NaP₂O₇·3H₂O

Abstract

Abstract The new trihydrate diphosphate, MnNH 4 NaP 2 O 7 ·3H 2 O, were synthesized and investigated by X‐ray diffraction and vibrational spectroscopy. Single crystal structure has been obtained using 1361 reflections with a final R value of 0.0564. This salt crystallizes in the monoclinic system, space group Cc, with Z = 4 and the following unit‐cell parameters: a = 10.1125(12), b = 16.4370(3), c = 5.5987(7) Å, β = 104.314° (9), V = 901.7 Å 3 . The atomic arrangement is a three‐dimensional framework built from P 2 O 7 4− diphosphate anions linked by MnO 6 , NaO 6 and NH 4 O 6 octahedra. The P 2 O 7 4− anion shows bent eclipsed configuration with bridge angle P‐O‐P of 125.9(4)°. The infrared and Raman spectra of this salt have been recorded and interpreted using factor group analysis. Most of the bands are observed in both infrared and Raman spectra, which confirms a non‐centrosymmetric space group. The apparence of υ as POP and υ s POP in infrared and Raman spectra point to a bent POP bridge in MnNH 4 NaP 2 O 7 ·3H 2 O. Copyright © 2003 John Wiley & Sons, Ltd.