Results of mass spectrometric measurements are reported which characterize the chemical bonding in the radical cations (CH3SiH)(.+) and (CH3)(2)Si-.+ and provide evidence for the existence of the corresponding neutral silylene molecules CH3SiH and (CH3)(2)Si in the gas phase. The experiments were performed with a modified four-sector ZAB mass spectrometer with a BEBE configuration and collision cells mounted in the intermediate field-free regions B(1)/E(1), E(1)/B(2), and B(2)E(2). Observed collisional activation (CA) mass spectra of the ions [H-4,C,Si](+) and [H-6,C-2,Si](+) generated from electron impact of tetramethylsilane and other precursors and CA/CA spectra of the [C,H-3,Si](+) derived from them are most compatible with the connectivities CH3SiH.+ and (CH3)(2)Si-.+. Neutralization-reionization (NRMS) experiments and CA experiments with the "recovery" signals established identical connectivities for the corresponding neutral species.