SDS Volume
Volume 73. Metal and Ammonium Formate Systems, p None
Source Publication
Sidgwick, N. V.; Gentle, J. A. H. R.; J. Chem. Soc. 121, 1837 (1922).
Conditions:
Room Temp: -1.82 - 170 °C
Compilers:
St. Trendafilova, Chr. Balarew
Methodology:
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.
Sample Information:
- 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.
Measurement Errors:
Ambient temperature: No information is given.
Mass concentration (m/v) (1): No information is given.
System 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.
| $T$ (°C) | 100w1 | $100 x_{1}$ | m1 (mol/kg) c | Phase (s) () b |
|---|---|---|---|---|
| -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.
