Infrared spectroscopic characterization of carbonated apatite: A combined experimental and computational study

Abstract

A combined experimental and computational approach was employed to investigate the feasibility and effectiveness of characterizing carbonated apatite (CAp) by infrared (IR) spectroscopy. First, an experimental comparative study was conducted to identify characteristic IR vibrational bands of carbonate substitution in the apatite lattice. The IR spectra of pure hydroxyapatite (HA), carbonate adsorbed on the HA surface, a physical mixture of HA and sodium carbonate monohydrate, a physical mixture of HA and calcite, synthetic CAps prepared using three methods (precipitation method, hydrothermal route, and solid-gas reaction at high temperature) and biological apatites (human enamel, human cortical bone, and two animal bones) were compared. Then, the IR vibrational bands of carbonate in CAp were calculated with density functional theory. The experimental study identified characteristic IR bands of carbonate that cannot be generated from surface adsorption or physical mixtures and the results show that the bands at ∼880, 1413, and 1450 cm(-1) should not be used as characteristic bands of CAp since they could result from carbonate adsorbed on the apatite crystals surface or present as a separate phase. The combined experimental and computational study reveals that the carbonate v3 bands at ∼1546 and 1465 cm(-1) are, respectively, the IR signature bands for type A CAp and type B CAp.

Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy

“…This is because both Mg 2+ and Na + can substitute for Ca 2+ in the HA lattice, while CO 3 2− can simultaneously substitute for PO 4 3− or OH − [47]. Theoretical calculations suggested that the precipitation of CDHA incorporated with Mg 2+ , Na + , CO 3 2− is more favorable than stoichiometric HA [49].…”

“…Due to asymmetric stretching ν 3 and out of plane bending ν 2 vibration mode, carbonate brand (CO 3 2− ) is present at 1473, 1446 and 856 cm −1 . The presence of the carbonate group in IR spectra is either surface absorption or incorporation of CO 3 [47]. Fig.…”

SEM-EDX Study of the Degradation Process of Two Xenograft Materials Used in Sinus Lift Procedures

“…The figure includes Type I collagen for comparison purposes. Above 1300 cm −1 , almost all the bands are exclusively assigned to collagen vibrations, the exception being those brought about by CO 3 2− at 1460 cm −1 , and a broad band present at 3500, which is attributed to the presence of the structural OH- groups [12,45,46]. …”

Transition from Endothermic to Exothermic Dissolution of Hydroxyapatite Ca5(PO4)3OH–Johnbaumite Ca5(AsO4)3OH Solid Solution Series at Temperatures Ranging from 5 to 65 °C

“…In contrast, the shift in the Raman bands attributed to P-O vibrations was irregular; we could not determine the reason for this behavior. (a) (c) (V) (a) (c) (V) The IR spectra of apatites have been investigated by many authors [2,[18][19][20][21][22][23][24]. The most intense absorption bands observed in the spectra are derived from PO 4 and AsO 4 ( Figure 6).…”