SDS Volume (4764)
Volume 73. Metal and Ammonium Formate Systems, p None
Original Measurements
Sokolov, N. M.; Minich, M. A.; Russ. J. Inorg. Chem. 6, 1293-5 (1961).
Variables:
Prepared by:
Method/Apparatus/Procedure:
A visual polythermal method was used.
Source and Purity of Materials:
- Component (1) was a commercial "chemically pure" material recrystallized from formic acid; it undergoes phase transitions at 60, 135 and 157°C [1]. Component (2) was prepared by reducing potassium nitrate with lead. It melted at 436°C after three recrystallizations. It undergoes a phase transition at 45°C [2].
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).
2
Berul', S. I.; Bergman, A. G.; Izv. Sektora Fiz. -Khim. Anal. 21, 178 (1952).
Components:
- Potassium formate, $\ce{ KCHO2 }$; [590-29-4] NIST WebBook
- Potassium nitrite, $\ce{ KNO2 }$; [7758-09-0] NIST WebBook
Experimental Data
Note: There is a eutectic at 107°C and 100 x2 = 33.5.
There is a peritectic at 143°C and 100 x2 = 44.
There is an intermediate compound incongruently melting.
The authors have tentatively assigned it the formula K2CHO2NO2.
Melting temperatures for different mole fractions
| $T_{\rm{m}}$ ($\pu{K}$) | $T_{\rm{m}}$ (°C) | $100 x_{2}$ |
|---|---|---|
| 441 | 168 | 0 |
| 436 | 163 | 5 |
| 428 | 155 | 1E+1 |
| 420 | 147 | 15 |
| 408 | 135 | 2E+1 |
| 403 | 130 | 25 |
| 392 | 119 | 3E+1 |
| 387 | 114 | 35 |
| 410 | 137 | 4E+1 |
| 442 | 169 | 45 |
| 472 | 199 | 5E+1 |
| 496 | 223 | 55 |
| 526 | 253 | 6E+1 |
| 551 | 278 | 65 |
| 578 | 305 | 7E+1 |
| 603 | 330 | 75 |
| 626 | 353 | 8E+1 |
| 649 | 376 | 85 |
| 672 | 399 | 9E+1 |
| 693 | 420 | 95 |
| 709 | 436 | 1E+2 |
(a) The T/K values were calculated the compiler.
