1. @C00907@ (with their @C01371@) derived by addition of a @H02904@ to a mononuclear @P04405@ of the nitrogen, chalcogen and halogen families.
    (H4N+) ammonium
    (H3O+) oxonium
    (H2F+) fluoronium
    (H4P+) phosphonium
    (H3S+) sulfonium
    (H2Cl+) chloronium
    (H4As+) arsonium
    (H3Se+) selenonium
    (H2Br+) bromonium
    (H4Sb+) stibonium
    (H3Te+) telluronium
    (H2I+) iodonium
    (H4Bi+) bismuthonium
  2. Derivatives formed by substitution of the above parent ions by univalent groups. The number of substituted hydrogen atoms is, especially in the case of @H02891@ substituents, indicated by the adjectives primary, secondary, tertiary or quaternary. E.g. (Cl2F+) dichlorofluoronium, (CH3)2S+H dimethylsulfonium (a secondary sulfonium ion), Cl(CH3)3P+ chlorotrimethylphosphonium, (CH3CH2)4N+ tetraethylammonium (a quaternary ammonium ion).
    See also:
    arsonium compounds
    halonium ions
    oxonium ions
    phosphonium compounds
    quaternary ammonium compounds
    stibonium compounds
    sulfonium compounds
  3. Derivatives formed by substitution of the above parent ions by groups having two or three free valencies on the same atom. Such derivatives are, where possible, designated by a specific class name. E.g. RC≡O+ hydrocarbylidyne @O04378@, R2C=N+H2X@I02958@, RC≡NH+@N04156@.
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1146 [Terms] [Paper]
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1353 [Terms] [Paper]