Vibrational Properties of Calcium Phosphate Compounds. 1. Raman Spectrum of β-Tricalcium Phosphate

Abstract

We present a study of the Raman spectrum of polycrystalline β-Ca3(PO4)2 (β-TCP) over its whole optical frequency range. Raman scattering bands associated with the normal vibrational modes of the PO4 3- tetrahedron were clearly identified, confirming the molecular character of the β-TCP crystal as regards to its vibrational properties. External lattice modes involving Ca2+ and PO4 3- sublattices were also observed. Several characteristic features of the spectrum are discussed in relation to the crystallographic structure of β-TCP.

Mechanism of Phosphorus Removal from Hanford Tank Sludge by Caustic Leaching

“…Figure 3.4 compares the Raman spectra of Ca 3 (PO 4 ) 2 , the residual Ca solids, and commercially procured Ca 5 (PO 4 ) 3 (OH). The Raman spectrum of the Ca 3 (PO 4 ) 2 used in this work agreed very well with that reported in the literature, with the ν 1 phosphate stretch split into two bands at 948 and 971 cm -1 , compared to the literature values of 949 and 970 cm -1 (de Aza et al 1997a). The Raman spectrum of the Ca residual was nearly identical to that of hydroxyapatite, although there was a minor difference in the band positions measured-a single ν 1 phosphate band was observed at 963 cm -1 for the residual Ca solids compared to 960 cm -1 for hydroxyapatite.…”

Development of valve train rig for assessment of cam/follower tribochemistry

“…Other components of the tribofilm within the wear scar are FeS 2 with peaks at 330-341 cm -1 . Narrow bands at 527-530cm -1 may be internal vibrations of PO 4 3- [48] or an iron oxide [47]. The peaks at 901-920 cm -1 are due to bending of the phosphate from the secondary antiwear additive.…”

Sol-gel bioactive glass-ceramics Part II: Glass-ceramics in the CaO-SiO2-P2O5-MgO system

“…In Ca-1 sample there were three sites for ν 4 4 3-) and 986 cm -1 (for ν 1 PO 4 3-) can be ascribed to the presence of β-TCP [36][37][38]. In Ca-1 and Ca-2 samples the absorption bands at 400, 402, 417, and 518 cm -1 could be ascribed to the presence of Mg-O bond [39].…”