IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Glass Ball as Bullet Solubility System: Potassium formate with Potassium nitrite
Components:
   (1) Potassium formate; KCHO2; [590-29-4]  NIST Chemistry WebBook for detail
   (2) Potassium nitrite; KNO2; [7758-09-0]  NIST Chemistry WebBook for detail
Original Measurements:
   Sokolov, N.M.; Minich, M.A., Zh. Neorg. Khim. 6, 2558-62. (1961*); Russ. J. Inorg. Chem. (Engl. Transl.) 6, 1293-5 (1961).

 Variables:


Prepared By:
   P. Baldini

 Experimental Remarks:
   Note: There is a eutectic at 107 ºC and 100x2 = 33.5.
      There is a peritectic at 143 ºC and 100x2 = 44.
     There is an intermediate compound incongruently melting.
      The authors have tentatively assigned it the formula K2CHO2NO2.

 Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)   
t/°CT/KMole Fraction2
168441  0
163436  5
15542810
14742015
13540820
13040325
11939230
11438735
13741040
16944245
19947250
223496  55
253526  60
278551  65
305578  70
330603  75
353626  80
376649  85
399672  90
420693  95
436709100
 Notes:
   a  The T/K values were calculated the compiler.

 Method/Apparatus/Procedure:
   A visual polythermal method was used.

 Source and Purity of Materials:
   Component (1) was a commercial "chemically pure" material recrystallized from formic acid; it undergoes phase transitions at 60, 135 and 157 °C.1 Component (2) was prepared by reducing potassium nitrate with lead. It melted at 436 °C after three recrystallizations. It undergoes a phase transition at 45 °C.2

 Estimated Errors:
   Solubility: No information is given.
   Temperature: The compiler estimates the accuracy of the temperature measurements to be probably ± 2 K.

 References:
   1N. M. Sokolov, Tezisy Dokl. X Nauch. Konf. S.M.I. (1956).
   2S. I. Berul' and A. G. Bergman, Izv. Sektora Fiz.-Khim. Anal. 21, 178 (1952).