The　viability　of　functionalization　of　the　semiconductor　surfaces　of　diamond　(100),　Si　(100),　and　Ge　(100)　by　traditional　[3　+　2]　cycloaddition　of　transition　metal　oxides　has　been　predicted　using　effective　cluster　models　in　the　framework　of　density　functional　theory.　The　cycloaddition　of　transition　metal　oxides　(OsO4,　RuO4,　and　MnO4-)　onto　the　X　(100)　(X=C,　Si,　and　Ge)　surface　is　much　more　facile　than　that　of　other　molecular　analogues　including　ethylene,　fullerene,　and　single-walled　carbon　nanotubes　because　of　the　high　reactivity　of　surface　dimers　of　X　(100).　Our　computational　results　demonstrate　the　plausibility　that　the　well-known　[3+2]　cycloaddition　of　transition　metal　oxides　to　alkenes　in　organic　chemistry　can　be　employed　as　a　new　type　of　surface　reaction　to　functionalize　the　semiconductor　X　(100)　surface,　which　offers　the　new　possibility　for　self-assembly　or　chemical　functionalization　of　X　(100)　at　low　temperature.　More　importantly,　the　chemical　functionalization　of　X　(100)　by　cycloaddition　of　transition　metal　oxides　provides　the　molecular　basis　for　preparation　of　semiconductor-supported　catalysts　but　also　strongly　advances　the　concept　of　using　organic　reactions　to　modify　the　solid　surface,　particularly　to　modify　the　semiconductor　C　(100),　Si　(100),　and　Ge　(100)　surfaces　for　target　applications　in　numerous　fields　such　as　microelectronics　and　heterogeneous　photocatalysis.　©　2009　American　Chemical　Society.