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A series of cobalt-exchanged hydroxyapatite (CoHAp) powders with different Ca/Co ratios and nominal unit-cell contents Ca10−xCox(PO4)6(OH)2, x = 0, 0.5, 1.0, 1.5 and 2.0, were synthesized by hydrothermal treatment of a precipitate at 473 K for 8 h. Based on ICP (inductively coupled plasma) emission spectroscopy analysis, it was established that the maximum amount of cobalt incorporation saturated at ∼12 at.% under these conditions. The effects of cobalt content on the CoHAp powders were investigated using ICP emission spectroscopy, particle size analysis, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) analyses as well as X-ray powder diffraction (XRPD) including Rietveld analysis. According to XRPD, all the materials are single-phase HAp and CoHAp of low crystallinity. Rietveld analysis shows that Co enrichment causes the c cell parameter to decrease at a faster rate than the a cell parameter. A microstructural analysis showed anisotropic X-ray line broadening due to crystallite size reduction. In CoHAp there is significant crystal elongation in [001], and the average size decreases with increasing cobalt content. The crystallite morphology transforms from rod-like for the pure HAp to lamellae at the highest degree of Co substitution. The results of Rietveld refinement (symmetry, size and morphology of the crystallites) were confirmed by TEM and HRTEM analysis.
Supporting information
For all compounds, program(s) used to refine structure: FULLPROF.
Crystal data top
HCa5O13P3 | V = 528.83 (1) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540562 Å |
Hall symbol: -P 6c | T = 293 K |
a = 9.4210 (1) Å | ?, ? × ? × ? mm |
c = 6.8800 (1) Å | |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Radiation source: X-ray tube | |
Refinement top
Rp = 9.494 | Profile function: pseudo-Voigt |
Rwp = 13.492 | 4 parameters |
Rexp = 10.132 | 4 restraints |
RBragg = 3.721 | |
χ2 = NOT FOUND | Background function: square polynomial for each range |
5096 data points | |
Crystal data top
HCa5O13P3 | V = 528.83 (1) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540562 Å |
a = 9.4210 (1) Å | T = 293 K |
c = 6.8800 (1) Å | ?, ? × ? × ? mm |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Refinement top
Rp = 9.494 | χ2 = NOT FOUND |
Rwp = 13.492 | 5096 data points |
Rexp = 10.132 | 4 parameters |
RBragg = 3.721 | 4 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Ca1 | 0.33330 | 0.66670 | 0.00092 | 0.01900* | |
Ca2 | 0.24525 | 0.99333 | 0.25000 | 0.01900* | |
P | 0.39811 | 0.36952 | 0.25000 | 0.01900* | |
O1 | 0.32711 | 0.48474 | 0.25000 | 0.01900* | |
O2 | 0.58616 | 0.46500 | 0.25000 | 0.01900* | |
O3 | 0.34152 | 0.25583 | 0.07261 | 0.01900* | |
O4 | 0.00000 | 0.00000 | 0.18819 | 0.01900* | |
(Co5HAp) cobalt exchanged hydroxyapatite
top
Crystal data top
Ca9.57Co0.43(PO4)6(OH)2 | V = 527.38 (3) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540560 Å |
Hall symbol: -P 6c | T = 293 K |
a = ? Å | ?, ? × ? × ? mm |
c = 6.8670 (2) Å | |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Radiation source: X-ray tube | |
Refinement top
Rp = 9.424 | Profile function: pseudo-Voigt |
Rwp = 12.024 | 28 parameters |
Rexp = 15.346 | 4 restraints |
RBragg = 5.094 | |
χ2 = NOT FOUND | Background function: square polynomial for each range |
5096 data points | |
Crystal data top
Ca9.57Co0.43(PO4)6(OH)2 | V = 527.38 (3) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540560 Å |
a = ? Å | T = 293 K |
c = 6.8670 (2) Å | ?, ? × ? × ? mm |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Refinement top
Rp = 9.424 | χ2 = NOT FOUND |
Rwp = 12.024 | 5096 data points |
Rexp = 15.346 | 28 parameters |
RBragg = 5.094 | 4 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
Ca1 | 0.33330 | 0.66670 | 0.00225 | 0.01900* | |
Co1 | 0.33330 | 0.66670 | 0.00225 | 0.01900* | 0.01359 |
Ca2 | 0.24490 | 0.99335 | 0.25000 | 0.01900* | 0.978 (3) |
Co2 | 0.24490 | 0.99335 | 0.25000 | 0.01900* | 0.03904 |
P | 0.39666 | 0.36968 | 0.25000 | 0.01900* | |
O1 | 0.32952 | 0.48825 | 0.25000 | 0.01900* | |
O2 | 0.58479 | 0.46372 | 0.25000 | 0.01900* | |
O3 | 0.34411 | 0.26013 | 0.06854 | 0.01900* | |
O4 | 0.00000 | 0.00000 | 0.17779 | 0.01900* | 0.50678 |
(Co10HAp) cobalt exchanged hydroxyapatite
top
Crystal data top
Ca9.05Co0.95(PO4)6(OH)2 | V = 524.81 (4) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540562 Å |
Hall symbol: -P 6c | T = 293 K |
a = 9.4039 (4) Å | ?, ? × ? × ? mm |
c = 6.8526 (4) Å | |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Radiation source: X-ray tube | |
Refinement top
Rp = 4.382 | Profile function: pseudo-Voigt |
Rwp = 5.550 | 36 parameters |
Rexp = 7.200 | 4 restraints |
RBragg = 3.841 | |
χ2 = NOT FOUND | Background function: square polynomial for each range |
5096 data points | |
Crystal data top
Ca9.05Co0.95(PO4)6(OH)2 | V = 524.81 (4) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540562 Å |
a = 9.4039 (4) Å | T = 293 K |
c = 6.8526 (4) Å | ?, ? × ? × ? mm |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Refinement top
Rp = 4.382 | χ2 = NOT FOUND |
Rwp = 5.550 | 5096 data points |
Rexp = 7.200 | 36 parameters |
RBragg = 3.841 | 4 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
Ca1 | 0.33330 | 0.66670 | 0.00279 | 0.01900* | 1.000 (9) |
Co1 | 0.33330 | 0.66670 | 0.00279 | 0.01900* | 0.052 (9) |
Ca2 | 0.24671 | 0.99608 | 0.25000 | 0.01900* | 0.958 (12) |
Co2 | 0.24671 | 0.99608 | 0.25000 | 0.01900* | 0.094 (12) |
P | 0.39606 | 0.36749 | 0.25000 | 0.01900* | |
O1 | 0.32980 | 0.48701 | 0.25000 | 0.01900* | |
O2 | 0.58438 | 0.46506 | 0.25000 | 0.01900* | |
O3 | 0.34435 | 0.25765 | 0.06824 | 0.01900* | |
O4 | 0.00000 | 0.00000 | 0.18325 | 0.01900* | 0.52604 |
(Co15HAp) cobalt exchanged hydroxyapatite
top
Crystal data top
Ca8.83Co1.17(PO4)6(OH)2 | V = 525.05 (4) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540560 Å |
Hall symbol: -P 6c | T = 293 K |
a = 9.4109 (4) Å | ?, ? × ? × ? mm |
c = 6.8456 (4) Å | |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Radiation source: X-ray tube | |
Refinement top
Rp = 3.396 | Profile function: pseudo-Voigt |
Rwp = 4.267 | 22 parameters |
Rexp = 5.533 | 4 restraints |
RBragg = 4.230 | |
χ2 = NOT FOUND | Background function: square polynomial for each range |
5096 data points | |
Crystal data top
Ca8.83Co1.17(PO4)6(OH)2 | V = 525.05 (4) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540560 Å |
a = 9.4109 (4) Å | T = 293 K |
c = 6.8456 (4) Å | ?, ? × ? × ? mm |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Refinement top
Rp = 3.396 | χ2 = NOT FOUND |
Rwp = 4.267 | 5096 data points |
Rexp = 5.533 | 22 parameters |
RBragg = 4.230 | 4 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
Ca1 | 0.33330 | 0.66670 | 0.00500 | 0.01900* | |
Co1 | 0.33330 | 0.66670 | 0.00500 | 0.01900* | 0.06105 |
Ca2 | 0.24759 | 0.99841 | 0.25000 | 0.01900* | 0.96239 |
Co2 | 0.24759 | 0.99841 | 0.25000 | 0.01900* | 0.09868 |
P | 0.39594 | 0.36777 | 0.25000 | 0.01900* | |
O1 | 0.33308 | 0.48992 | 0.25000 | 0.01900* | |
O2 | 0.58404 | 0.46711 | 0.25000 | 0.01900* | |
O3 | 0.34558 | 0.25591 | 0.07011 | 0.01900* | |
O4 | 0.00000 | 0.00000 | 0.17821 | 0.01900* | 0.53051 |
(Co20HAp) cobalt exchanged hydroxyapatite
top
Crystal data top
Ca8.85Co1.15(PO4)6(OH)2 | V = 524.21 (4) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540560 Å |
Hall symbol: -P 6c | T = 293 K |
a = ? Å | ?, ? × ? × ? mm |
c = 6.8400 (2) Å | |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Radiation source: X-ray tube | |
Refinement top
Rp = 3.942 | Profile function: pseudo-Voigt |
Rwp = 4.933 | 38 parameters |
Rexp = 6.353 | 4 restraints |
RBragg = 3.720 | |
χ2 = NOT FOUND | Background function: square polynomial for each range |
5096 data points | |
Crystal data top
Ca8.85Co1.15(PO4)6(OH)2 | V = 524.21 (4) Å3 |
Mr = ? | Z = 2 |
Hexagonal, P63/M | X-ray radiation, λ = 1.540560 Å |
a = ? Å | T = 293 K |
c = 6.8400 (2) Å | ?, ? × ? × ? mm |
Data collection top
Philips 1050 diffractometer | 2θmin = 8°, 2θmax = 110°, 2θstep = 0.02° |
Refinement top
Rp = 3.942 | χ2 = NOT FOUND |
Rwp = 4.933 | 5096 data points |
Rexp = 6.353 | 38 parameters |
RBragg = 3.720 | 4 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
Ca1 | 0.33333 | 0.66667 | 0.00311 | 0.01900* | 1.00 (3) |
Co1 | 0.33333 | 0.66667 | 0.00311 | 0.01900* | 0.03 (3) |
Ca2 | 0.24657 | 0.99761 | 0.25000 | 0.01900* | 0.91 (2) |
Co2 | 0.24657 | 0.99761 | 0.25000 | 0.01900* | 0.12 (2) |
P | 0.39627 | 0.36770 | 0.25000 | 0.01900* | |
O1 | 0.33249 | 0.48918 | 0.25000 | 0.01900* | |
O2 | 0.58452 | 0.46578 | 0.25000 | 0.01900* | |
O3 | 0.34295 | 0.25749 | 0.06836 | 0.01900* | |
O4 | 0.00000 | 0.00000 | 0.17498 | 0.01900* | 0.51464 |
Experimental details
| (HAp) | (Co5HAp) | (Co10HAp) | (Co15HAp) |
Crystal data |
Chemical formula | HCa5O13P3 | Ca9.57Co0.43(PO4)6(OH)2 | Ca9.05Co0.95(PO4)6(OH)2 | Ca8.83Co1.17(PO4)6(OH)2 |
Mr | ? | ? | ? | ? |
Crystal system, space group | Hexagonal, P63/M | Hexagonal, P63/M | Hexagonal, P63/M | Hexagonal, P63/M |
Temperature (K) | 293 | 293 | 293 | 293 |
a, c (Å) | 9.4210 (1), 6.8800 (1) | ?, 6.8670 (2) | 9.4039 (4), 6.8526 (4) | 9.4109 (4), 6.8456 (4) |
V (Å3) | 528.83 (1) | 527.38 (3) | 524.81 (4) | 525.05 (4) |
Z | 2 | 2 | 2 | 2 |
Radiation type | X-ray, λ = 1.540562 Å | X-ray, λ = 1.540560 Å | X-ray, λ = 1.540562 Å | X-ray, λ = 1.540560 Å |
Specimen shape, size (mm) | ?, ? × ? × ? | ?, ? × ? × ? | ?, ? × ? × ? | ?, ? × ? × ? |
|
Data collection |
Diffractometer | Philips 1050 diffractometer | Philips 1050 diffractometer | Philips 1050 diffractometer | Philips 1050 diffractometer |
Specimen mounting | ? | ? | ? | ? |
Data collection mode | ? | ? | ? | ? |
Scan method | ? | ? | ? | ? |
2θ values (°) | 2θmin = 8 2θmax = 110 2θstep = 0.02 | 2θmin = 8 2θmax = 110 2θstep = 0.02 | 2θmin = 8 2θmax = 110 2θstep = 0.02 | 2θmin = 8 2θmax = 110 2θstep = 0.02 |
|
Refinement |
R factors and goodness of fit | Rp = 9.494, Rwp = 13.492, Rexp = 10.132, RBragg = 3.721, χ2 = NOT FOUND | Rp = 9.424, Rwp = 12.024, Rexp = 15.346, RBragg = 5.094, χ2 = NOT FOUND | Rp = 4.382, Rwp = 5.550, Rexp = 7.200, RBragg = 3.841, χ2 = NOT FOUND | Rp = 3.396, Rwp = 4.267, Rexp = 5.533, RBragg = 4.230, χ2 = NOT FOUND |
No. of data points | 5096 | 5096 | 5096 | 5096 |
No. of parameters | 4 | 28 | 36 | 22 |
No. of restraints | 4 | 4 | 4 | 4 |
| (Co20HAp) |
Crystal data |
Chemical formula | Ca8.85Co1.15(PO4)6(OH)2 |
Mr | ? |
Crystal system, space group | Hexagonal, P63/M |
Temperature (K) | 293 |
a, c (Å) | ?, 6.8400 (2) |
V (Å3) | 524.21 (4) |
Z | 2 |
Radiation type | X-ray, λ = 1.540560 Å |
Specimen shape, size (mm) | ?, ? × ? × ? |
|
Data collection |
Diffractometer | Philips 1050 diffractometer |
Specimen mounting | ? |
Data collection mode | ? |
Scan method | ? |
2θ values (°) | 2θmin = 8 2θmax = 110 2θstep = 0.02 |
|
Refinement |
R factors and goodness of fit | Rp = 3.942, Rwp = 4.933, Rexp = 6.353, RBragg = 3.720, χ2 = NOT FOUND |
No. of data points | 5096 |
No. of parameters | 38 |
No. of restraints | 4 |
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