IUPAC-NIST Solubility Database
NIST Standard Reference Database 106


Glass Ball as Bullet Solubility System: Cobalt formate with Water

Components:
   (1) Cobalt formate; Co(CHO2)2; [544-18-3]  NIST Chemistry WebBook for detail
   (2) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

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

Variables:
   Temperature = 10 ºC to 80 ºC

Prepared By:
   Chr.Balarew and St. Trendafilova

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)
  
Solubility polytherm of the Co(CHO2)2-H2O system.
t/°CPhaseMass Fraction w1m1 [mol kg-1]aSolid Phase(s)b
10Liquid2.030.139A
15Liquid2.180.150A
20Liquid2.340.161A
25Liquid2.440.168A
30Liquid2.550.176A
35Liquid2.690.186A
40Liquid2.850.197A
45Liquid3.050.211A
50Liquid3.330.231A
55Liquid3.410.237A
60Liquid3.590.250A
65Liquid3.790.264A
70Liquid4.020.281A
75Liquid4.190.294A
80Liquid4.280.300A
Notes:
   a  These values were calculated by the compilers.
   b  The solid phase is: A = Co(CHO2)2•2H2O.

Method/Apparatus/Procedure:
   The decrease of supersaturation was studied isothermally in about a 2% excess of formic acid to suppress hydrolysis of the salt. Equilibrium was reached in 15-20 h. The cobalt concentration was determined using Complexone III at pH 5.5-6 with Xylenol orange as indicator. The composition of the solid phase was determined by x-ray diffraction and chemical analysis.

Source and Purity of Materials:
   Cobalt formate was prepared by neutralizing basic cobalt carbonate with dilute formic acid.

Estimated Errors: