Laser-ablated group 6 metal atoms react with, silane to form inserted SiH3-MH hydride intermediates, which are identified from M-H and Si-H stretching modes. Following two successive alpha-H-transfers, the HSi MH3 (M = Mo, W) silylidyne molecules are produced. These silicon-metal triple-bonded species are identified as major products from the strong. M-H stretching modes through deuterium substitution and comparison with frequencies and intensities from density functional calculations and from the analogous methylidynes. The silylidynes have calculated C-3v structures and longer Si-H bonds than silane, but the C-3v methylidyne analogues have shorter C-H bonds than methane. The Si Mo and Si W bonds are polarized differently and have slightly lower effective bond orders than their carbon analogues. In addition, calculations for the group 6 silylidene molecules reveal C-s structures with no evidence of agostic distortion, in contrast to the corresponding methylidene molecules.