Ammonium dihydrogenphosphate with Ammonium chloride and Water (IUPAC SDS Volume 66)
Evaluator
Jitka Eysseltová Department of Inorganic Chemistry, Charles University
Evaluation
7.6 NH4H2PO4-NH4Cl-H2O

Figure 18 presents isotherms for the NH4H2PO4-NH4Cl-H2O system at 0°C1 and 20°C.2 The comparison appears to be reasonable and the isotherms in each of these reports can be accepted tentatively.

Figure
Solubility graph
FIG. 18. Solubility isotherms in the NH4H2PO4–NH4Cl–H2O system.
Sources:

1 Askenasy, P.; Nessler, F.; Z. Anorg. Allg. Chem. 189, 305 (1930).
2 Volkov, A. A.; Sosnina, O. E.; Uch. Zap. Perm. Univ. 1970, 229, 35.