Table 1.

Selected CaP phases of interest for biomedical applications [[21], [22], [23], [24], [25], [26]].

Ca/P Molar Ratio	CaP phase Name	Formula	pH Stability Range	Density (g/cm3)
0.5	MCPM (monobasic calcium phosphate monohydrate)	Ca(H2PO4)2·H2O	0.0–2.0	2.22
1.0	DCPA (dicalcium phosphate anhydrous)	CaHPO4	2.0–5.5 (>80 ​°C)	2.929
1.0	DCPD (dibasic calcium phosphate dehydrate)	CaHPO4·2H2O	2.0–6.0	2.319
1.3	OCP (octa calcium phosphate)	Ca8(HPO4)2(PO4)4·5H2O	5.5–7.0	2.673
1.5	TCP (tricalcium phosphate)	Ca3(PO4)2	–	2.814
1.2–2.2	ACP (amorphous calcium phosphate)	CaxHy(PO4)z·nH2O n ​= ​3–4.5 15%–20% H2O	5–12	–
1.5–1.67	CDHAp (calcium deficient hydroxyapatite)	Ca10-x (HPO4) x (PO4)6-x (OH)2-x (0 ​< ​x ​< ​2)	6.5–9.5	–
1.67	HAp (Hydroxyapatite)	Ca10(PO4)6(OH)2	9.5–12.0	3.155
2.0	TTCP (tetra calcium phosphate)	Ca4(PO4)2O	–	3.056