SDS Volume (4737)
Volume 73. Metal and Ammonium Formate Systems, p None
Original Measurements
Dmitrevskaya, O. I.; Russ. J. Gen. Chem. 28, 295-300 (1958).
Variables:
Prepared by:
Method/Apparatus/Procedure:
A visual polythermal method was used. The temperatures were measured with a Nichrome-Constantan thermocouple.
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°C [1].
Estimated Errors:
Ambient temperature: The compiler estimates the accuracy of the temperature measurements to be probably ±2 K.
Mass concentration (m/v) (1): No information is given.
References
1 Sokolov, N. M.; Tezisy Dokl. X Nauch. Konf. S. M. I. (1956).
Components:
- Potassium formate, $\ce{ KCHO2 }$; [590-29-4] NIST WebBook
- Sodium formate, $\ce{ NaCHO2 }$; [141-53-7] NIST WebBook
Experimental Data
Note: There is one eutectic at 168°C and 100 x1 = 49.5; and another at 167°C and 100 x2 = 4. There is also an intermediate compound, (CHO2)4K3Na, with a congruent melting point at 182°C (compiler).
Melting temperatures for different mole fractions
| $T_{\rm{m}}$ ($\pu{K}$) | $T_{\rm{m}}$ (°C) | $100 x_{1}$ |
|---|---|---|
| 531 | 258 | 0 |
| 525 | 252 | 5 |
| 519 | 246 | 1E+1 |
| 513 | 240 | 15 |
| 505 | 232 | 2E+1 |
| 495 | 222 | 25 |
| 482 | 209 | 3E+1 |
| 471 | 198 | 35 |
| 459 | 186 | 4E+1 |
| 449 | 176 | 45 |
| 441 | 168 | 49.5 |
| 442 | 169 | 5E+1 |
| 445 | 172 | 55 |
| 449 | 176 | 6E+1 |
| 452 | 179 | 65 |
| 453 | 180 | 7E+1 |
| 455 | 182 | 75 |
| 454 | 181 | 8E+1 |
| 452 | 179 | 85 |
| 446 | 173 | 9E+1 |
| 440 | 167 | 96 |
| 441 | 168 | 97 |
| 444 | 171 | 98 |
| 442 | 169 | 99 |
| 441 | 168 | 99.5 |
| 440 | 167 | 1E+2 |
(a) The T/K values were calculated the compiler.
