Compilation - Ammonium dihydrogenphosphate with Ammonium fluorosilicate and Water (IUPAC SDS Volume 66)
SDS Volume (2866)
Volume 66. Ammonium Phosphates, p None
Original Measurements
Morgunova, E. M.; Maslova, N. D.; Golovina, V. I.; Zh. Neorg. Khim. 1972, 17, 2006.
Variables:
Composition and temperature
Prepared by:
Method/Apparatus/Procedure:
The isothermal method was used. The samples were equilibrated in polyethylene vessels at 25 °C and 50 °C, and in ebonite vessels at 75 °C and 90 °C. Equilibrium was attained in three weeks at 25 °C, in seven days at 50 °C and in two days at 75 °C and 90 °C. The composition of the solid phases was determined by the Schreinemakers' method. Ammonium was determined by the distillation method. $\ce{[SiF6]^{2-}}$ was determined by precipitation as $\ce{K2[SiF6]}$ [1].
Source and Purity of Materials:
- $\ce{(NH4)2[SiF6]}$ was prepared from reagent grade $\ce{H2[SiF6]}$ (MRTU 609-4821-67) and recrystallized. $\ce{NH4H2PO4}$ was prepared as described by others [2].
Estimated Errors:
Ambient temperature: The temperature was controlled to within ±0.1 K. No other information is given.
Mass concentration (m/v) (1): No information is given.
References
1
Ricci, J. E.; Skarulis, J. A.; J. Am. Chem. Soc. 1951, 73, 3624.
2
Karyakin, Yu. V.; Chistye Khimicheskie Reaktivy, Moscow, p. 58 (1947).
Components:
- Ammonium dihydrogenphosphate, $\ce{ NH4H2PO4 }$; [7722-76-1] NIST WebBook
- Ammonium fluorosilicate, $\ce{ (NH4)2[SiF6] }$; [16919-19-0] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Solubility isotherms in the (NH4)2[SiF6]-NH4H2PO4-H2O system.
| $T$ (°C) | 100w1 | 100w2 | 100w3 | m1 (mol/kg) | m2 (mol/kg) | Phase (s) () |
|---|---|---|---|---|---|---|
| 25 | 18.70 | 81.30 | 1.29 | A | ||
| 25 | 18.01 | 1.66 | 80.33 | 1.26 | 0.18 | A |
| 25 | 16.59 | 3.38 | 80.03 | 1.16 | 0.37 | A |
| 25 | 15.47 | 5.62 | 78.91 | 1.10 | 0.62 | A |
| 25 | 13.50 | 9.33 | 77.17 | 0.98 | 1.05 | A |
| 25 | 12.42 | 11.50 | 76.08 | 0.92 | 1.31 | A |
| 25 | 11.59 | 13.48 | 74.93 | 0.87 | 1.56 | A |
| 25 | 10.96 | 15.20 | 73.84 | 0.83 | 1.79 | A |
| 25 | 10.11 | 16.93 | 72.96 | 0.78 | 2.02 | A |
| 25 | 9.55 | 18.02 | 72.43 | 0.74 | 2.16 | A |
| 25 | 9.26 | 19.48 | 71.26 | 0.73 | 2.38 | A |
| 25 | 8.59 | 21.34 | 70.07 | 0.69 | 2.65 | A |
| 25 | 7.97 | 22.42 | 69.61 | 0.64 | 2.80 | A |
| 25 | 7.80 | 23.60 | 68.60 | 0.64 | 2.99 | A + B |
| 25 | 7.06 | 24.53 | 68.41 | 0.58 | 3.12 | B |
| 25 | 5.45 | 25.87 | 68.68 | 0.45 | 3.27 | B |
| 25 | 3.65 | 26.89 | 69.46 | 0.29 | 3.37 | B |
| 25 | 1.84 | 28.11 | 70.05 | 0.15 | 3.49 | B |
| 25 | 29.77 | 70.23 | 3.69 | B | ||
| 50 | 25.77 | 74.23 | 1.95 | A | ||
| 50 | 22.13 | 7.17 | 70.70 | 1.76 | 0.88 | A |
| 50 | 17.26 | 13.57 | 69.17 | 1.40 | 1.71 | A |
| 50 | 12.77 | 21.54 | 65.69 | 1.09 | 2.85 | A |
| 50 | 9.75 | 27.34 | 62.91 | 0.87 | 3.78 | A |
| 50 | 7.80 | 31.72 | 60.48 | 0.72 | 4.56 | A + B |
| 50 | 4.07 | 35.13 | 60.80 | 0.38 | 5.02 | B |
| 50 | 43.95 | 56.05 | 6.82 | B | ||
| 75 | 32.30 | 67.70 | 2.68 | A | ||
| 75 | 25.16 | 8.88 | 65.96 | 2.14 | 1.17 | A |
| 75 | 20.69 | 15.07 | 64.24 | 1.81 | 2.04 | A |
| 75 | 7.17 | 42.35 | 50.48 | 0.80 | 7.29 | A + B |
| 75 | 6.30 | 44.33 | 49.37 | 0.72 | 7.81 | B |
| 75 | 3.30 | 46.26 | 50.44 | 0.37 | 7.97 | B |
| 75 | 55.66 | 44.34 | 10.91 | B | ||
| 90 | 35.82 | 64.18 | 3.13 | A | ||
| 90 | 33.16 | 1.14 | 65.70 | 2.83 | 0.15 | A |
| 90 | 27.08 | 9.71 | 63.21 | 2.40 | 1.34 | A |
| 90 | 22.06 | 16.48 | 61.46 | 2.01 | 2.33 | A |
| 90 | 17.72 | 24.27 | 58.01 | 1.71 | 3.64 | A |
| 90 | 18.86 | 27.21 | 53.93 | 1.96 | 4.39 | A |
| 90 | 11.17 | 38.52 | 50.31 | 1.25 | 6.66 | A |
| 90 | 9.02 | 43.18 | 47.80 | 1.06 | 7.85 | A |
| 90 | 7.13 | 46.95 | 45.92 | 0.87 | 8.89 | A |
| 90 | 6.40 | 48.44 | 45.16 | 0.80 | 9.32 | A + B |
| 90 | 4.98 | 48.74 | 46.28 | 0.60 | 9.16 | B |
| 90 | 2.82 | 51.17 | 46.01 | 0.34 | 9.67 | B |
| 90 | 1.11 | 51.87 | 47.02 | 0.13 | 9.59 | B |
| 90 | 61.85 | 38.15 | 14.09 | B |
(a) These values were calculated by the compiler. The unit is: mol kg-1.
(b) The solid phases are: A = (NH4)2[SiF6]; B = NH4H2PO4.
