IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Magnesium formate with Boric acid and Water

Components:
   (1) Boric acid; H3BO3; [10043-35-3]  NIST Chemistry WebBook for detail
   (2) Magnesium formate; Mg(CHO2)2; [557-39-1]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Kalacheva, V.G.; Eremeeva, I.L.; Schwartz, E.M., Izv. Acad. Nauk. Latv. SSR, Ser. Khim. N 4, 406-9 (1977).

Variables:

   Concentration = Composition at 50 ºC

Prepared By:
   Chr. Balarew and St. Trendafilova

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

Solubility values in the Mg(CHO₂)₂-H₃BO₃-H₂O system at 50 °C.
Chemical₁	Phase	Mass Fraction w₁	m₁ [mol kg-1]^a	Chemical₂	Mass Fraction w₂	m₂ [mol kg-1]^a	Solid Phase(s)^b
Mg(CHO2)2	Liquid	---	---	H3BO3	10.35	1.867	A
Mg(CHO2)2	Liquid	3.74	0.379	H3BO3	10.05	1.885	A
Mg(CHO2)2	Liquid	5.02	0.517	H3BO3	10.05	1.914	A
Mg(CHO2)2	Liquid	5.57	0.577	H3BO3	10.04	1.924	A
Mg(CHO2)2	Liquid	9.50	1.03	H3BO3	9.95	2.00	A
Mg(CHO2)2	Liquid	12.20	1.368	H3BO3	9.83	2.04	A
Mg(CHO2)2	Liquid	12.32	1.384	H3BO3	9.84	2.04	A
Mg(CHO2)2	Liquid	12.40	1.395	H3BO3	9.88	2.06	A
Mg(CHO2)2	Liquid	12.80	1.448	H3BO3	9.88	2.07	A
Mg(CHO2)2	Liquid	13.02	1.480	H3BO3	10.06	2.115	A+B
Mg(CHO2)2	Liquid	13.68	1.465	H3BO3	4.65	0.921	B
Mg(CHO2)2	Liquid	13.70	1.427	H3BO3	2.33	0.449	B
Mg(CHO2)2	Liquid	13.72	1.391	H3BO3	---	---	B

Notes:
   ^a  The molality values were calculated by the compilers.
   ^b  The solid phases are: A = H₃BO₃; B = Mg(CHO₂)₂•2H₂O.

Method/Apparatus/Procedure:
   The isothermal method was used. The mixtures were shaken in sealed glass vessels for 5-6 hrs. The boric acid concentration was determined by titration with alkali using mannitol. The Mg²⁺ content was determined complexometrically using Complexon III. The composition of the solid phases was determined by the Schreinemakers method.

Source and Purity of Materials:
   p.a. grade boric acid was recrystallized from water. Magnesium formate dihydrate was obtained by the reaction of Mg(OH) ₂ and formic acid. The solid was recrystallized twice from water.

Estimated Errors:

   Temperature: The temperature was controlled to within ± 0.02 °C.