IUPAC-NIST Solubility Database
NIST Standard Reference Database 106


Glass Ball as Bullet Solubility System: Strontium formate with Copper formate and Water

Components:
   (1) Copper formate; Cu(CHO2)2; [544-19-4]  NIST Chemistry WebBook for detail
   (2) Strontium formate; Sr(CHO2)2; [592-89-2]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Vasileva, V., Cryst. Res.Technol. 30, 339-343 (1995).

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 Sr(CHO2)2-Cu(CHO2)2-H2O system at 50 °C.
Chemical1PhaseMass Fraction w1m1 [mol kg-1]aChemical2Mass Fraction w2m2 [mol kg-1]aSolid Phase(s)b
Cu(CHO2)2Liquid25.172.190Sr(CHO2)20.000.00A
Cu(CHO2)2Liquid23.352.74Sr(CHO2)26.730.542A
Cu(CHO2)2Liquid22.812.291Sr(CHO2)212.301.068A
Cu(CHO2)2Liquid24.012.673Sr(CHO2)217.501.684A
Cu(CHO2)2Liquid25.072.929Sr(CHO2)219.201.939eutonic
Cu(CHO2)2Liquid24.312.800Sr(CHO2)219.161.902B
Cu(CHO2)2Liquid21.982.433Sr(CHO2)219.201.837B
Cu(CHO2)2Liquid19.862.133Sr(CHO2)219.531.814B
Cu(CHO2)2Liquid17.511.813Sr(CHO2)219.601.754B
Cu(CHO2)2Liquid15.681.585Sr(CHO2)219.901.713B
Cu(CHO2)2Liquid14.101.417Sr(CHO2)221.021.826eutonic
Cu(CHO2)2Liquid12.601.221Sr(CHO2)220.231.695C
Cu(CHO2)2Liquid8.010.706Sr(CHO2)218.131.382C
Cu(CHO2)2Liquid4.750.399Sr(CHO2)217.761.290C
Cu(CHO2)2Liquid0.000.00Sr(CHO2)217.161.166C
Notes:
   a  The molality values were calculated by the compilers.
   b  The solid phases are: A = Cu(CHO2)2•2H2O; B = CuSr(CHO2)4•4H2O; C = Sr(CHO2)2•2H2O.

Method/Apparatus/Procedure:
   The solubility in the system was studied by the Khlopin method of isothermal decrease of supersaturation.1 Equilibrium was reached in 10-15 hr. Cu2+ was determined complexometrically at pH 5.5-6.0 using Xylenol Orange as indicator. Sr2+ was also determined complexometrically at pH 11 using Thymolphtalexon as indicator. The solid phase composition was determined by the graphic method of Schreinemakers for wet residues. X-ray diffraction analysis, DT and TG analysis were also used.

Source and Purity of Materials:
   The formates of copper and strontium were prepared by dissolving copper carbonate, and strontium carbonate respectively, in diluted formic acid. The reagents used were "p.a.".

Estimated Errors:

   Temperature: Not given.

References:
   1Chr. Balarew, V. Karaivanova, and T. Oikova, Comm. Dept. Chem. Bulg. Acad. Sci. 3, 637 (1970).