Table 2.

Wavenumbers, chemical groups and description of the FT-IR spectrum of RB, HA-900, HA-1000 and HA-1100.

Sample code and Wavenumber (cm−1)				Chemical group	Description	References
RB	HA-900	HA-1000	HA-1100
563, 601	570, 601	570, 601	570, 601	PO43−	bending mode	[3], [4], [5], [12], [13], [14]
671, 3417	632, 3417	632, 3417	632, 3417	OH−	OH− ions prove presence of HA	[3], [4], [7], [12], [13], [14]
1033, 1134	1049, 1095	1049, 1095	1049, 1095	PO43−	Antisymmetric stretching mode	[1], [3], [4], [5], [9], [12], [13], [14]
1412, 1466, 1643,	1411, 1465, 1550, 1643, 2152, 2345	1411, 1465, 1643, 2152, 2345	1411, 1465, 1643, 2553	CO32−	Substitutes phosphate ion, B-type HA (i.e. CO3 substituting for PO4) is formed	[2], [6], [7], [8], [9], [12], [13], [14]
2862, 2924	2931	2924	2924	Adsorbed water	Under influence of thermal treatment, absorption band becomes narrower	[2], [8], [9], [12], [13], [14]