1H NMR, 31P NMR and Raman Study of CaHPO4and SrHPO4

Abstract

CaHPO4and SrHPO4were investigated using Raman, 1HNMR and 31PNMR techniques to study the environment of their PO43- tetrahedra and the percentage of mobile protons. ‘HNMR spectra at room temperature suggest the presence of three types of protons, in agreement with RX investigation. The percentage of mobile protons in SrHPO4is greater than in CaHPO4because Sr2+is bigger than Ca2+. 31P NMR spectra at room temperature show two lines in the spectrum of SrHPO4, revealing an equal environment of two sets of pairs of PO43-. The 31P NMR spectrum of CaHPO4, however, exhibits three lines. This result was confirmed using a cross polarization (CP) sequence program. The first peak is attributed to the first set of pairs of P(1)O4units and the two other ones to P(2)O4and P(2’)O4units. © 2005, Verlag der Zeitschrift für Naturforschung. All rights reserved.