Table 2.
Properties of the major CaPs obtained from aqueous solutions [21]
| Name | Chemical formula | Ca/P ratio | Solubility at 25ºC, -log(Ks) | Solubility at 25ºC (g L−1) | pH stability range at 25ºC |
|---|---|---|---|---|---|
| MCPM | Ca(H2PO4)2·H2O | 0.5 | 1.14 | ~ 18 | 0.0–2.0 |
| DCPD | CaHPO4·2H2O | 1.0 | 6.59 | ~ 0.088 | 2.0–6.0 |
| OCP | Ca8(HPO4)2(PO4)4·5H2O | 1.33 | 96.6 | ~ 0.0081 | 5.5–7.0 |
| ACP | CaxHy(PO4)z·nH2O, n = 3–4.5; 15–20% H2O | 1.2–2.2 | a | a | ~ 5–12 |
| CDHA | Ca10-x(HPO4)x(PO4)6-x(OH)2 (0 < x < 1) | 1.5–1.67 | ~ 85 | ~ 0.0094 | 6.5–9.5 |
| HAp | Ca10(PO4)6(OH)2 | 1.67 | 116.8 | ~ 0.0003 | 9.5–12 |
| FAp | Ca10(PO4)F2 | 1.67 | 120.0 | ~ 0.0002 | 7–12 |
MCPM monocalcium phosphate monohydrate, DCPD (brushite) dicalcium phosphate dehydrate, OCP octacalcium phosphate, FAp fluorapatite
aMetastable, no exact value due to various variables