IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Glass Ball as Bullet Solubility System: Potassium formate with Potassium chloride
Components:
   (1) Potassium formate; KCHO2; [590-29-4]  NIST Chemistry WebBook for detail
   (2) Potassium chloride; KCl; [7447-40-7]  NIST Chemistry WebBook for detail
Original Measurements:
   Leonesi, D.; Braghetti, M.; Cingolani, A.; Franzosini, P., Z. Naturforsch. 25a, 52-5 (1970).

 Variables:


Prepared By:
   P. Baldini

 Experimental Remarks:
   Note 1: In the original paper the results were shown in graphical form. The numerical values listed above were given in a personal communication from one of the authors (F. P.) to the compiler.
Note 2: The system could not be investigated above about 300 ºC due to thermal instability of the formate.
Note 3: There is a eutectic at 163.5 ºC and 100x2 = 3.7.
Note 4: According to the authors, the trend of the liquidus branch richer in component 1 is close to ideal, and the formation of solid solutions in this region ought to be either insignificant or, at least, contained within narrow limits. Previous investigations by the same group2 stated that the cryometric constant of potassium formate was K = 11.5 ± 0.1 K molality-1 and that
lim (ΔT/m) = 11.6 K molality-1
m→=0                                      
(ΔT is the experimental freezing point constant and m is the molality of the solute) when KCl was the solute.

 Experimental Data:   (Notes on the Nomenclature)
  
t/°CT/KMole Fraction2
168.7441.90
168.3441.50.20
168.1441.30.43
167.7440.90.60
167.4440.60.84
166.7439.91.06
165.7438.91.83
165.5438.71.98
165.0438.22.55
164.3437.52.95
163.8437.03.46
163.6436.83.67
163.6436.83.75
166.6439.83.78
172.1445.34.02
176.6449.84.16
179.2452.4  4.22
183.5456.7  4.45
195.8469.0  4.96
218.4491.6  6.09
244.0517.2  7.50
270.1543.3  9.02
299.7572.911.16
 Method/Apparatus/Procedure:
   A Pyrex device, suitable for work under an inert atmosphere, and allowing one to observe the system visually, was used (for details, refer to Ref. 1). The initial crystallization temperatures were measured with a Chromel-Alumel thermouple checked by comparison with a certified Pt resistance thermometer, and connected to a L&N Type K-3 potentiometer.

 Source and Purity of Materials:
   C. Erba RP materials, dried by heating under vacuum, were used.

 Estimated Errors:
   Solubility: No information is given.
   Temperature: The compiler estimates the accuracy of the temperature measurements to be probably ± 0.1 K.

 References:
   1M. Braghetti, D.Leonesi, and P. Franzosini, Ric. Sci. 38, 116 (1968).
   2D. Leonesi, C. Piantoni, G. Berchiesi, and P. Franzosini, Ric. Sci. 38, 702 (1968).