Carbene analoguesIUPAC Term

The electrically neutral mononuclear hydrides of group 14 having two non-bonding electrons, the electrically neutral mononuclear hydrides of group 15 having four non-bonding electrons, and also the compound HB:. The names of a number of these are shown below. br/   table class table table-condensed tr td RB: /td td boranylidenes /td td RAs: /td td arsanylidenes /td /tr tr td RN: /td td nitrenes /td td R sub 2 /sub Sn: /td td stannylidenes /td /tr tr td R sub 2 /sub Si: /td td silylenes /td td RSb: /td td stibanylidenes /td /tr tr td RP: /td td phosphanylidenes /td td R sub 2 /sub Pb: /td td plumbylidenes /td /tr tr td R sub 2 /sub Ge: /td td germylidenes /td td/ td/ /tr /table Note that if R H, these compounds are parent hydrides; derivatives formed by substitution are named accordingly. However, if the substituent's first atom, bearing the free valence, is of the same element as the atom of the carbene analogue, other parent compounds may be required (see carbenes ), e.g. HN: nitrene; CH sub 3 /sub N: methylnitrene; H sub 2 /sub NN: diazanylidene (synonym isodiazene, not aminonitrene).