Extending the chemistry of disilene fluoride adducts studied earlier by us, we investigated the formation of 1,1-bis(trimethylsilyl)-fluorodiphenylsilylsilanide, which was prepared by reaction of (Me3Si)(3)SiSiPh2F with (KOBu)-Bu-t. The formed FPh2SiSi(Me3Si)(2)K displays distinctively different structural and spectroscopic features compared to the earlier reported F(Me3Si)(2)SiSi(SiMe3)(2)K. While the latter eliminates metal fluoride upon reaction with MgBr2, the respective magnesium silanide is formed from FPh2SiSi(Me3Si)(2)K. Reaction of (Me3Si)(3)SiSiPh2Cl with KO'Bu proceeded similarly, but the formed ClPh2SiSi(Me3Si)(2)K easily undergoes potassium chloride elimination to the disilene Ph2Si=Si(SiMe3)(2). Compared to F(Me3Si)(2)SiSi(SiMe3)(2)K, which can be regarded as a disilene fluoride adduct, structural, spectroscopic, and reactivity properties of FPh2SiSi(Me3Si)(2) K distinguish it as a beta-fluorodisilanide.