[chemical substances]
   reactive intermediates
     Class diradicals [X:, X•Y•]
       01 Class boranylidenes [RB:]
       02 Class carbenes [X2C:, X=C:]
       03 Class nitrenes [RN:]
       04 Class silylenes [R2Si:]
       05 Class phosphanylidenes [RP:]
       06 Class germylidenes [R2Ge:]
       07 Class arsanylidenes [RAs:]
       08 Class stannylidenes [R2Sn:]
       09 Class stibanylidenes [RSb:]
       10 Class plumbylidenes [R2Pb:]
       11 Class fulminates [RON=C:]