Vibrational properties of calcium phosphate compounds .1. Raman spectrum of beta-tricalcium phosphate

We present a study of the Raman spectrum of polycrystalline beta-Ca-3(PO4)(2) (beta-TCP) over its whole optical frequency range. Raman scattering bands associated with the normal vibrational modes of the PO43- tetrahedron were clearly identified, confirming the molecular character of the beta-TCP crystal as regards to its vibrational properties. External lattice modes involving Ca2+ and PO43- sublattices were also observed. Several characteristic features of the spectrum are discussed in relation to the crystallographic structure of beta-TCP.