K. Vivekanandan et al., RAMAN AND FT-IR STUDIES OF PB-4(NO3)(2)(PO4)(2)CENTER-DOT-2H(2)O CRYSTAL, Materials chemistry and physics, 39(4), 1995, pp. 284-289
Lead nitrate phosphate single crystals were grown in silica hydrogel a
t room temperature. A controlled reaction was employed between orthoph
osphoric acid and lead nitrate solution by the slow diffusion process
in the gel medium. The laser Raman and FT-IR spectra of the lead nitra
te phosphate crystal were recorded. The vibrational assignments of PO4
3-, NO3- and H2O vibrations have been approximated in terms of T-d, D-
3h and C-2v symmetry species, respectively. The vibrational modes of P
O43- ion indicate that this ion is distorted in this crystal and its s
ymmetry is lowered to free ion symmetry. The vibrational spectrum indi
cates that the NO3- ion is slightly distorted in the crystal. From the
spectrum the presence of water molecules is indicated.