IUPAC-NIST Solubility Database
NIST Standard Reference Database 106


Glass Ball as Bullet Solubility System: Magnesium formate with Zinc formate and Water

Components:
   (1) Magnesium formate; Mg(CHO2)2; [557-39-1]  NIST Chemistry WebBook for detail
   (2) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
   (3) Zinc formate; Zn(CHO2)2; [557-41-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Stoilova, D.; Balarew, C.; Vassileva, V., St. Russeva, Zh. Neorg. Khim. 26, 1641 (1981).

Variables:

   Concentration = Composition at 80 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-Zn(CHO2)2-H2O system at 80 °C.
Chemical1PhaseMass Fraction w1m1 [mol kg-1]aChemical2Mass Fraction w2m2 [mol kg-1]aSolid Phase(s)bDistribution CoefficientMg2+/Zn2+Distribution CoefficientZn2+/Mg2+
Zn(CHO2)2Liquid14.881.125Mg(CHO2)20.000.00A------
Zn(CHO2)2Liquid13.931.055Mg(CHO2)21.110.114B0.342.94
Zn(CHO2)2Liquid11.450.871Mg(CHO2)23.960.409B0.333.03
Zn(CHO2)2Liquid10.570.807Mg(CHO2)25.160.536B0.352.86
Zn(CHO2)2Liquid9.860.757Mg(CHO2)26.330.661B0.363.00
Zn(CHO2)2Liquid9.150.708Mg(CHO2)27.690.809B0.432.33
Zn(CHO2)2Liquid7.050.540Mg(CHO2)29.010.939B0.442.27
Zn(CHO2)2Liquid6.510.504Mg(CHO2)210.411.096B0.432.33
Zn(CHO2)2Liquid4.280.331Mg(CHO2)212.541.318B0.472.13
Zn(CHO2)2Liquid4.130.320Mg(CHO2)212.801.348B0.561.79
Zn(CHO2)2Liquid3.340.257Mg(CHO2)213.051.365B0.651.54
Zn(CHO2)2Liquid2.190.168Mg(CHO2)213.941.454B0.641.56
Zn(CHO2)2Liquid1.020.079Mg(CHO2)216.181.709B0.721.39
Zn(CHO2)2Liquid0.000.00Mg(CHO2)216.521.731C------
Notes:
   a  The molality values were calculated by the compilers.
   b  The solid phases are: A= Zn(CHO2)2•2H2O; B = (Zn,Mg)(CHO2)2•2H2O; C = Mg(CHO2)2•2H2O.

Method/Apparatus/Procedure:
   Equilibrium was reached in 15-20 hrs using the isothermal decrease of supersaturation method. The sum of the Mg2+ and Zn2+ content of both phases was determined using Complexon III at pH 9-10 and Eriochrome Black T as indicator. Zn2+ was determined using Complexon III at pH 5.5-6.0 with Xylenol Orange as indicator. The composition of the suction-dried mixed crystals was determined by the method of algebraic indirect identification of the solid phase.1

Source and Purity of Materials:
   The zinc and magnesium formates were prepared by dissolving the normal or basic carbonates in dilute formic acid.

Estimated Errors:
   Solubility: The solubilities were determined in a slight excess of formic acid.
   Temperature: Not given.

References:
   1D. Trendafelov and Chr. Balarew, Comm. Dept. Chem. Bulg. Acad. Sci. 1 , 73 (1968).