Figure 1. FTIR spectra of synthesized apatite at different
temperature. (b) Table shows the peak positions of different assignments
related to PO43- and OH bonds at
different temperatures.
Across all temperatures, we detected the high intensity bands in the
range 561-606 cm-1 that are assigned to the ν4” out
of plane and ν4”’ bending modes of the
PO43- unit. Moreover, the intense
infrared bands between 1023-1099 cm-1, which are
attributed to the PO43- ν3’ and ν3”’
stretching vibrations, were observed. Furthermore, infrared bands
between 960-965 cm-1, known as the
PO43- ν1 symmetric stretching
vibrational mode were observed.
Weak infrared peaks were also seen at 865-870 cm-1 for
the precipitate formed at 90ᵒC and for the HAp
Captal® R spectra respectively, which corresponds to
the carbonate groups (CO32-). This
confirms the previous findings of Okazaki37 who stated
that the 875 cm-1 corresponds to
CO32- groups substituted with
PO43- tetrahedron (type B carbonated
apatite), and when shifted to a lower frequency, it indicates higher
degree of fluoridation. This is due to the conformation of the carbonate
groups in the lattice are significantly affected by the
F- content.
Table 1 : Peak positions of different assignments related to
PO43-, OH, and
CO32- bands at different temperatures.