Effects of pH and Ca/P molar ratio on the quantity and crystalline structure of calcium phosphates obtained from aqueous solutionsEffets du pH et du ratio molaire Ca/P sur la quantité et la structure cristalline des phosphates de calcium obtenus à partir de solutions aqueuses.

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Table II.

Characteristics of the suspensions and precipitates of calcium phosphates obtained at drifting pH (* traces of OCP). Precipitate analyses performed using XRD and FTIR.

Initial conditions		Terminal conditions							Precipitate characterization
pH	Ca/P	pH	∆pH	Precipitated calcium		Precipitated phosphate		Ca/P	XRD		FTIR
				mmol·L⁻¹	% total	mmol·L⁻¹	% total
6.70	1.00	4.84	1.86	5.60	28.00	5.33	26.65	1.05	Brushite		Brushite
6.70	1.50	4.61	2.09	7.90	26.33	7.07	35.35	1.12	Brushite		Brushite
6.70	2.00	4.48	2.22	7.17	17.93	4.28	21.40	1.67	Brushite		Brushite
7.50	1.00	5.75	1.75	17.40	87.00	13.63	68.15	1.28	Brushite		Brushite
7.50	1.50	5.36	2.14	14.96	49.87	14.99	74.95	1.00	Brushite		Brushite
7.50	2.00	5.13	2.37	14.91	37.28	15.26	76.30	0.98	Brushite		Brushite
8.50	1.00	5.83	2.67	15.20	76.00	11.87	59.35	1.28	Brushite		Brushite
8.50	1.50	5.6	2.90	17.53	58.43	17.03	85.15	1.03	Brushite		Brushite
8.50	2.00	5.37	3.13	15.15	37.88	17.06	85.30	0.89	Brushite		Brushite
9.50	1.00	5.96	3.54	16.40	82.00	12.93	64.65	1.27	Brushite	OCP^*	Brushite
9.50	1.50	5.5	4.00	16.73	55.77	14.82	74.10	1.13	Brushite	OCP^*	Brushite
9.50	2.00	5.4	4.10	15.24	38.10	16.97	84.85	0.90	Brushite	OCP^*	Brushite