The stabilization of complex fluoroanions derived from weakly acidic parent fluorides is a significant and ongoing challenge. The [SF5](-) anion is recognized as one such case, and only a limited number of [SF5](-) salts are known to be stable at room temperature. In the present study, glyme-coordinated alkali metal cations (K+, Rb+, and Cs+) are employed to stabilize [SF5](-), which provides a simple synthetic route to a [SF5](-) salt. The reactivities of KF and RbF with SF4 are significantly enhanced by complexation with G4, based on Raman spectroscopic analyses. A new room-temperature stable salt, [Cs(G(4))(2)][SF5] (G4 = tetraglyme), was synthesized by stoichiometric reaction of CsF, G4, and SF4. The vibrational frequencies of [SF5](-) were assigned based on quantum chemical calculations, and the shift of the G4 breathing mode accompanying coordination to metal cations was confirmed by Raman spectroscopy. Single-crystal X-ray diffraction revealed that Cs+ is completely isolated from [SF5](-) by two G4 ligands and [SF5](-) is disordered along the crystallographic two-fold axis. Hirshfeld surface analysis reveals that the H center dot center dot center dot H interaction between two neighboring [Cs(G4)(2)](+) moieties is more dominant on the Hirshfeld surface than the interaction between the H atom in glyme molecules and the F atom in [SF5](-), providing a CsCl-type structural model where the large and spherical [Cs(G(4))(2)](+) cations contact each other and the [SF5](-) anions occupy interstitial spaces in the crystal lattice. The [SF5](-) anion, combined with [Cs(G(4))(2)](+), exhibits a very limited deoxofluorinating ability toward hydroxyl groups in both neat conditions and THE solutions.