Compilation - Rubidium formate with Water (IUPAC SDS Volume 73)
SDS Volume (4829)
Volume 73. Metal and Ammonium Formate Systems, p None
Original Measurements
Sidgwick, N. V.; Gentle, J. A. H. R.; J. Chem. Soc. 121, 1837 (1922).
Variables:
Room Temp: -1.82 - 170 °C
Prepared by:
St. Trendafilova, Chr. Balarew
Method/Apparatus/Procedure:
The freezing points were measured in a Beckmann apparatus. Analysis was done gravimetrically by evaporating the solution to dryness. At higher temperatures mixtures were sealed in tubes and the temperature at which the last crystal disappeared on warming was observed.
Source and Purity of Materials:
- The rubidium formate was prepared by neutralizing the carbonate with formic acid. Commercial 80% formic acid was distilled in a vacuum at 70°C with enough sulfuric acid to remove the water.
Estimated Errors:
Ambient temperature: No information is given.
Mass concentration (m/v) (1): No information is given.
Components:
- Rubidium formate, $\ce{ RbCHO2 }$; [3495-35-0] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Melting point of rubidium formate determined to be 107°C. Phase composition at 16.5°C B + C and at 51°C C + D.
Composition of equilibrium liquid phase
| $T$ (°C) | 100w1 | $100 x_{1}$ | m1 (mol/kg) | Phase (s) () |
|---|---|---|---|---|
| -1.82 | 6.23 | 0.909 | 0.509 | A |
| -5.62 | 15.93 | 2.549 | 1.452 | A |
| -7.82 | 20.62 | 3.463 | 1.991 | A |
| -10.62 | 25.79 | 4.573 | 2.663 | A |
| -13.88 | 30.62 | 5.744 | 3.382 | A |
| 3.3 | 78.86 | 33.97 | 28.59 | B |
| 7.8 | 80.71 | 36.59 | 32.06 | B |
| 9.5 | 81.37 | 37.59 | 33.47 | B |
| 14.0 | 83.59 | 41.09 | 39.04 | B |
| 16.3 | 84.61 | 43.12 | 42.13 | B |
| 28.3 | 85.6 | 45.1 | 45.6 | C |
| 43.6 | 87.77 | 49.75 | 55.00 | C |
| 49.9 | 89.23 | 53.34 | 63.49 | C |
| a | 89.23 | 53.34 | 63.49 | D |
| 60.8 | 90.06 | 55.55 | 69.43 | D |
| 101.7 | 93.89 | 67.95 | 117.8 | D |
(a) Metastable point.
(b) The solid phases are: A = ice; B = RbCHO2·H2O; C = RbCHO2·0.5H2O; D = RbCHO2.
(c) The molality values were calculated by the compilers.
