Molybdenum sulfide tetrafluoride was synthesized from MoF6 and S(Si(CH3)(3))(2) in CFCl3 at low temperature and was fully characterized by Raman, infrared, and F-19 NMR spectroscopy and by X-ray crystallography. The crystal structure revealed that MoSF4 forms infinite fluorine-bridged chains. Quantum-chemical calculations using B3LYP and PBE1PBE methods were used to calculate the gas-phase geometry and vibrational frequencies of monomeric MoSF4 and (MoSF4)(3)F-. The vibrational frequencies of (MoSF4)(3)F- have been used in the assignment of the vibrational spectra of solid MoSF4. Natural bond order analyses were carried out for monomeric MoSF4 and, for comparison, for WSF4.