IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Calcium formate with Phosphoric acid and Water

Components:
   (1) Calcium formate; Ca(CHO2)2; [544-17-2]  NIST Chemistry WebBook for detail
   (2) Phosphoric acid; H3PO4; [7664-38-2]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Kuanisheva, N.A., Khazikhanova, B.H.; Kalacheva, V.G., Zh. Neorg. Khim. 31, 2426-8 (1986).

Variables:

   Concentration = Composition at 25 ºC

Prepared By:
   Chr. Balarew and St. Trendafilova

Experimental Remarks:

   The molality values were calculated by the compilers.

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)

Solubility values in the Ca(CHO₂)₂-H₃PO₄-H₂O system at 25 °C.
Chemical₁	Phase	Mass Fraction w₁	m₁ [mol kg-1]	Chemical₂	Mass Fraction w₂	m₂ [mol kg-1]	Chemical₃	Mass Fraction w₃	m₃ [mol kg-1]	Chemical₄	Mass Fraction w₄	m₄ [mol kg-1]	Solid Phase(s)^a
CaO	Liquid	7.41	1.427	P2O5	0	0	Ca(CHO2)2	17.19	1.595	H3PO4	---	---	A
CaO	Liquid	5.26	0.995	P2O5	0.51	0.038	Ca(CHO2)2	12.20	1.076	H3PO4	0.697	0.082	B
CaO	Liquid	5.06	0.957	P2O5	0.66	0.049	Ca(CHO2)2	11.73	1.032	H3PO4	0.906	0.106	B
CaO	Liquid	4.25	0.801	P2O5	1.15	0.086	Ca(CHO2)2	9.86	0.856	H3PO4	1.593	0.184	B
CaO	Liquid	4.2	0.793	P2O5	1.4	0.104	Ca(CHO2)2	9.74	0.847	H3PO4	1.933	0.223	C
CaO	Liquid	4.47	0.883	P2O5	5.24	0.409	Ca(CHO2)2	10.37	0.967	H3PO4	7.235	0.896	C
CaO	Liquid	6.0	1.305	P2O5	12.00	1.031	Ca(CHO2)2	13.92	1.539	H3PO4	16.569	2.433	D
CaO	Liquid	4.11	0.973	P2O5	20.58	1.925	Ca(CHO2)2	9.53	1.180	H3PO4	28.417	4.674	E
CaO	Liquid	2.33	0.622	P2O5	30.83	3.249	Ca(CHO2)2	5.40	0.798	H3PO4	42.570	8.350	E
CaO	Liquid	2.8	0.679	P2O5	23.68	2.269	Ca(CHO2)2	6.49	0.820	H3PO4	32.69	5.485	E

Notes:
   ^a  The solid phases are: A = Ca(CHO₂)₂; B = Ca(CHO₂)₂ + CaHPO₄; C = CaHPO₄; D = Ca(H₂PO₄)₂•H₂O + CaHPO₄; E = Ca(H₂PO₄)₂.

Method/Apparatus/Procedure:
   The isothermal method was used. Equilibrium was attained in 5-6 hours. The glass vessels in the thermostat were coated with glycerin.

Source and Purity of Materials:
   75% p.a. grade H₃PO₄ was used. p.a. grade calcium formate was recrystallized.

Estimated Errors:

   Temperature: t = ±0.1 °C.