IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Potassium formate with Sodium formate

Components:
   (1) Potassium formate; KCHO2; [590-29-4]  NIST Chemistry WebBook for detail
   (2) Sodium formate; NaCHO2; [141-53-7]  NIST Chemistry WebBook for detail

Original Measurements:
   Dmitrevskaya, O.I., Zh. Obshch. Khim. 28, 299-304 (1958)*; Russ J. Gen. Chem. (Engl. Transl.) 28, 295-300 (1958).

Variables:

Prepared By:
   P. Baldini

Experimental Remarks:

   Note: There is one eutectic at 168 ºC and 100x₁ = 49.5; and another at 167 ºC and 100x₂ = 4. There is also an intermediate compound, (CHO₂)₄K₃Na, with a congruent melting point at 182 ºC (compiler).

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)


t/°C	T/K	10⁰ * Mole Fraction₁
258	531	0
252	525	5
246	519	10
240	513	15
232	505	20
222	495	25
209	482	30
198	471	35
186	459	40
176	449	45
168	441	49.5
169	442	50
172	445	55
176	449	60
179	452	65
180	453	70
182	455	75
181	454	80
179	452	85
173	446	90
167	440	96
168	441	97
171	444	98
169	442	99
168	441	99.5
167	440	100

Notes:
   ^a  The T/K values were calculated the compiler.

Method/Apparatus/Procedure:
   A visual polythermal method was used. The temperatures were measured with a Nichrome-Constantan thermouple.

Source and Purity of Materials:
   "Chemically pure" materials were recrystallized and dried to a constant weight. Component (1) undergoes phase transitions at 60, 135 and 157 °C.¹ Component (2) undergoes a phase transition at 242 °C¹

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).