SDS Volume (3012)
Volume 66. Ammonium Phosphates, p None
Original Measurements
Bergman, A. G.; Opredelenkova, L. V.; Dzuev, A. B.; Ukr. Khim. Zh. 33, 285 (1967).
Variables:
Temperature and composition.
Prepared by:
Method/Apparatus/Procedure:
A visual polythermic method was used [1]. The appearance of the first crystals as well as the disappearance of the last crystals was observed, the difference between these values being kept to a minimum.
Source and Purity of Materials:
- Reagent grade urea and $\ce{NH4H2PO4}$ were recrystallized and dried before being used. Their melting points were 132.5°C and 200°C, respectively.
Estimated Errors:
Ambient temperature: No information is given.
Mass concentration (m/v) (1): No information is given.
References
1 Bergman, A. G.; Luzhnaya, N. P.; Fiziko-Khimicheskie Osnovy Izucheniya i Ispol'zovaniya Solyanykh Mestorozhdeniy Khlorid-Sul'fatnogo Tipa, Moscow, IAN USSR (1951).
Components:
- Ammonium dihydrogenphosphate, $\ce{ NH4H2PO4 }$; [7722-76-1] NIST WebBook
- Urea, $\ce{ CH4N2O }$; [57-13-6] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Additional Data: Solubility polytherm and solubility isotherms in the temperature range -10°C to +50°C are given, but only in graphical form.
Relative areas of crystallization fields are: ice = 9.98 %, α-NH4H2PO4 = 8.01 %; β-NH4H2PO4 = 62.18 %; -α-CO(NH2)2 = 4.99 %; β-CO(NH2)2 = 2.28 %; γ-CO(NH2)2 = 12.56 %.
Composition and crystallization temperature of invariant points in the NH4H2PO4-CO(NH2)2-H2O system.
| $T$ (°C) | 100w1 | 100w2 | 100w3 | m1 (mol/kg) | m2 (mol/kg) | Phase (s) () |
|---|---|---|---|---|---|---|
| -17.5 | 30.0 | 13.5 | 56.5 | 8.84 | 2.08 | A + B + C |
| -6.0 | 35.0 | 14.5 | 50.5 | 11.5 | 2.50 | B + C + D |
| 28.0 | 51.5 | 15.0 | 33.5 | 25.6 | 3.89 | C + D + E |
| 46.0 | 58.0 | 15.0 | 27.0 | 35.8 | 4.83 | D + E + F |
(a) The molality values were calculated by the compiler.
(b) The solid phases are: A = ice; B = α-NH4H2PO4; C = α-CO(NH2)2; D = β-NH4H2PO4; E = β-CO(NH2)2; F = γ-CO(NH2)2.
