Generic name for H2Si: and substitution derivatives thereof, containing an electrically neutral bivalent silicon atom with two non-bonding electrons. (The definition is analogous to that given for carbene.)
The silanediyl group (H2Si), analogous to the methylene group (H2C).
Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1164 (https://doi.org/10.1351/pac199466051077)