IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

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 Solubility System: Sodium formate with Formic Acid and Water

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Components:
   (1) Formic acid; CH2O2; [64-18-6]  NIST Chemistry WebBook for detail
   (2) Sodium formate; NaCHO2; [141-53-7]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Elöd, E.; Tremmel, K., Z. Anorg. Allg. Chem. 165, 161 (1927).

Variables:

   Concentration = Composition and temperature

Prepared By:
   T. A. Ageyeva

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

Solubility values in the NaCHO₂-CH₂O₂-H₂O system.

T/K	Chemical1	Mass Fraction w1	100 * Mole Fraction1a	Chemical2	Mass Fraction w2	Mole Fraction2a	Chemical3	Mass Fraction w3	Mole Fraction3a	Solid Phase(s)b
298.2 K	NaCHO2	26.0	19.2	CH2O2	74.0	80.8	H2O	0.0	0.0	A
298.2 K	NaCHO2	31.2	18.9	CH2O2	54.8	49.1	H2O	14.0	32.0	A
298.2 K	NaCHO2	37.2	20.2	CH2O2	39.2	31.5	H2O	23.6	48.4	A
298.2 K	NaCHO2	37.8	19.8	CH2O2	35.4	27.4	H2O	26.8	52.9	B
298.2 K	NaCHO2	40.8	19.7	CH2O2	24.8	17.7	H2O	34.4	62.6	B
298.2 K	NaCHO2	42.4	18.6	CH2O2	14.1	9.16	H2O	43.5	72.2	B
298.2 K	NaCHO2	43.1	18.9	CH2O2	12.7	8.20	H2O	44.2	73.0	B
298.2 K	NaCHO2	43.3	18.8	CH2O2	11.7	7.50	H2O	45.0	73.7	B
298.2 K	NaCHO2	43.7	18.9	CH2O2	10.6	6.75	H2O	45.7	74.4	C
298.2 K	NaCHO2	39.8	14.9	CH2O2	0.0	0.0	H2O	60.2	85.1	C
296.6 K	NaCHO2	28.9	21.6	CH2O2	71.1	78.4	H2O	0.0	0.0	A
296.6 K	NaCHO2	41.3	24.4	CH2O2	40.8	35.6	H2O	17.9	39.9	A + B
296.6 K	NaCHO2	40.6	23.3	CH2O2	39.2	33.2	H2O	20.1	43.5	B
296.6 K	NaCHO2	49.0	21.6	CH2O2	6.5	4.2	H2O	44.5	74.1	B + D
296.6 K	NaCHO2	48.5	21.1	CH2O2	5.7	3.7	H2O	45.8	75.2	D
296.6 K	NaCHO2	46.7	18.8	CH2O2	0.0	0.0	H2O	53.3	81.2	D
296.6 K	NaCHO2	41.26	24.38	CH2O2	40.80	35.62	H2O	17.94	40.00	A + B
296.6 K	NaCHO2	41.18	24.27	CH2O2	40.73	35.48	H2O	18.09	40.25	A + B
296.6 K	NaCHO2	49.03	21.65	CH2O2	6.51	4.25	H2O	44.46	74.10	B + D
296.6 K	NaCHO2	49.15	21.75	CH2O2	6.55	4.28	H2O	44.30	73.97	B + D
318.2 K	NaCHO2	34.9	26.6	CH2O2	65.1	73.4	H2O	0.0	0.0	A
318.2 K	NaCHO2	40.5	26.8	CH2O2	49.6	48.5	H2O	9.9	24.7	A + B
318.2 K	NaCHO2	52.0	24.6	CH2O2	9.4	6.6	H2O	38.6	68.9	B + E
318.2 K	NaCHO2	52.5	23.2	CH2O2	2.4	1.6	H2O	45.1	75.2	E
318.2 K	NaCHO2	52.7	22.8	CH2O2	0.0	0.0	H2O	47.3	77.2	E
318.2 K	NaCHO2	40.52	26.80	CH2O2	49.55	48.42	H2O	9.93	24.8	A + B
318.2 K	NaCHO2	40.83	27.17	CH2O2	49.58	48.75	H2O	9.59	24.1	A + B
318.2 K	NaCHO2	52.00	24.56	CH2O2	9.35	6.53	H2O	38.65	68.91	B + E
318.2 K	NaCHO2	52.50	24.94	CH2O2	9.25	6.49	H2O	38.25	68.57	B + E

Notes:
   ^a  These values were calculated by the compiler.
   ^b  The solid phases are: A = NaCHO₂•CH₂O₂; B = 3NaCHO₂•CH₂O₂; C = NaCHO₂•3H₂O₂; D = NaCHO₂•2H₂O₂; E = NaCHO₂.

Method/Apparatus/Procedure:
   The isothermal method was used. The sodium formate content was determined by the method of Lieben. Formic acid was determined acidimetrically. The solid phases were identified with a polarizable microscope and analyzed gravimetrically.

Source and Purity of Materials:
   No information is given.

Estimated Errors:

   Temperature: The temperature was controlled to within ± 0.05 °C.

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Last updated: February 18, 2015 (Created: August 17, 2007)