Correlation between Raman wavenumbers and P?O bond lengths in crystalline inorganic phosphates

TLDR: A linear empirical correlation was established between Raman stretching wavenumbers of phosphorus-oxygen bonds and their bond lengths in inorganic crystalline phosphates as discussed by the authors, which can be applied to glassy and amorphous phosphate materials (GAMs).

Abstract: A linear empirical correlation was established between Raman stretching wavenumbers of phosphorus–oxygen bonds and their bond lengths in inorganic crystalline phosphates. Although established on samples of inorganic crystalline phosphates, the correlation can be applied to glassy and amorphous phosphate materials (GAMs). Their unpolarized vibrational spectra are often similar because they are determined largely by short-range order. The correlation was used to predict PO bond length in the α-form of Li3PO4, which is stable over only a small range of temperatures below the melting-point. It can also be used to estimate the length of PO single bonds, terminal PO and OPO chain bonds and terminal double bonds in many technologically important amorphous materials containing phosphate groups. This correlation is expected to offer invaluable insight into the structures of phosphate species for which diffraction or other spectroscopic techniques provide incomplete structural information. That would enhance the value of Raman spectroscopy as a complementary technique in structural studies of phosphates. Copyright © 2004 John Wiley & Sons, Ltd.