In this study we predict, based on our ab initio electronic structure calculations, the existence and relative stabilities of several new species such as H3SMgF3, H2SMgF2, and HSMgF derived from combining the geometrically metastable and electronically stable parent doubly charged ions H4S+2 and MgF4-2. Although this study focuses on compounds obtained from these particular double ions, we suggest that analogous observations will be obtained when other double ions are used. Stable structures of the HSMgF, and H2SMgF2 molecules, as well as a local energy minimum and two different second-order saddle point geometries for the H3SMgF3 molecule were found. The lowest-energy stable structure is that found for H3SMgF3, which is best described as a dative adduct of H2S, MgF2, and HF, and which lies approximately 570 kcal/mol below the separated-ion starting materials and approximately 140 kcal/mol below the (H4S+2) (MgF4-2) contact ion pair.