In general, glasses have a random structure, but they can take on unique structures due to bond selectivity. In this paper, we introduce the bond selectivity of oxygen- and fluorine-containing glasses and the formation of glass structures derived from the bond selectivity of each anion. We present the relationship between BaMgBO₃F crystals and BaF₂-MgO-B₂O₃ glasses. The crystal is composed of oxide and fluoride layers. The corresponding glass is suggested to have a bicontinuous structure from structural analysis and simulation. The glass has a favorable structure for luminescence and shows higher luminescence efficiency than the corresponding crystal. Such a structure is also favorable for nucleation; the BaF₂-ZnO-B₂O₃ glass precipitated fluoride crystals with a very small particle size distribution at 5 nm upon heat treatment. Various structural analyses suggest that the fluoride sites in the fluoride-rich domain of this glass structure are similar to the crystals. This paper suggests that various functionalities can be developed by utilizing the mixing heterogeneity derived from the selective binding of fluoride and oxide.