Quaternary reciprocal systems of alkali metal fluorides, chlorides, and bromides were partitioned into simplexes by a geometric method and a graph method. Phase transformations and chemical reactions in the bordering ternary reciprocal systems were described. Conversion lines were experimentally studied, and information on crystallizing phases within the composition prisms of the M1,M2‖F,Cl,Br systems (M1 and M2 are group 1 s-block elements) was obtained.