IUPAC-NIST Solubility Database
NIST Standard Reference Database 106


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

Components:
   (1) Manganese formate; Mn(CHO2)2; [3251-96-5]  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:
   Balarew, C.; Stoilova, D.; Vassileva, V., J. Solid State Chem. 57, 260-6 (1985).

Variables:

   Concentration = Composition at 25 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 Mn(CHO2)2-Zn(CHO2)2-H2O system at 25 °C.
Chemical1PhaseMass Fraction w1m1 [mol kg-1]aChemical2Mass Fraction w2m2 [mol kg-1]aSolid Phase(s)bDistribution CoefficientMn2+/Zn2+Distribution CoefficientZn2+/Mn2+
Mn(CHO2)2Liquid6.280.462Zn(CHO2)20.000.00A------
Mn(CHO2)2Liquid5.380.398Zn(CHO2)21.290.089B0.681.47
Mn(CHO2)2Liquid4.200.309Zn(CHO2)22.020.139B0.741.36
Mn(CHO2)2Liquid2.500.183Zn(CHO2)23.200.218B0.591.70
Mn(CHO2)2Liquid0.000.00Zn(CHO2)25.380.366C------
Notes:
   a  The molality values were calculated by the compiler.
   b  The solid phases are: A = Mn(CHO2)2•2H2O; B = (Mn,Zn)(CHO2)2•2H2O; C = Zn(CHO2)2•2H2O.

Method/Apparatus/Procedure:
   The method used was the isothermal decrease of supersaturation. The Mn2+ content of the liquid and solid phases was determined complexometrically at pH 9.5-1 0 using Eriochrome Black T as indicator after masking Zn2+ as cyanide. The sum of Mn2+ and Zn2+ was also determined complexometrically using Xylenol Orange at pH 5.5 as indicator. The composition of the suction-dried solid phase was calculated using the algebraic indirect identification of solid phase composition method.1 The mixed crystals were also studied by x-ray diffraction.

Source and Purity of Materials:
   The reagents used were of p. a. grade. The manganese and zinc formates were prepared by action of dilute formic acid on manganese and basic zinc carbonates, respectively.

Estimated Errors:
   Solubility: The solubility of the salts was determined in a slight excess of formic acid (about 2%) to suppress salt hydrolysis.
   Temperature: Not given.

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