This paper presents a theoretical and experimental study of the N{{a}^{ + }}, S{{r}^{{2 + }}}||{{F}^{{-}}}, MoO₄^{2 - } three-component reciprocal system. The partition of the composition square to simplexes was modeled. The thermodynamic method confirmed the variant with NaF–SrF2–SrMoO4, NaF–2NaF·Na2MoO4–SrMoO4, and 2NaF·Na2MoO4–SrMoO4–Na2MoO4 three-phase triangles. Experimentally the partition was confirmed by the X-ray powder diffraction (XRD) analysis of a 50 equiv. % Na2MoO4 and 50 equiv. % SrF2 mixture, whose composition corresponds to the full conversion point. A phase tree was designed, and the main chemical reactions in the mixtures corresponding to equivalence points were described. A series of polythermal sections was studied by differential thermal analysis (DTA) and thermogravimetry (TG), from which the directions to three invariant points were determined. The coordinates of the eutectic point and two peritectic points were identified. All invariant points lie inside the 2NaF·Na2MoO4–SrMoO4–Na2MoO4 phase triangle. The phase assemblage of the system is represented by five crystallization fields of sodium fluoride, strontium fluoride, strontium molybdate, an incongruently melting compound, and sodium molybdate-base terminal solid solutions. The smallest crystallization fields are those of the compound 2NaF·Na2MoO4 and the sodium molybdate-base terminal solid solution.
Matveev et al. (Sat,) studied this question.