previous home next

Lewis Acid/Base Interaction Matrix Database

Type 9 Lewis Acid/Base Complexation Chemistry

Reduction of Onium Ion
Bonding: Hydride ions do not form 1:1 complexes with onium ions because the Brønsted basic, nucleophilic, reducing hydride ion will initiate a proton abstraction reaction.
Charge: A reaction always occurs, rather than forming a Lewis acid/base complex so the idea of a charge on a complex is not applicable.

If the onium ion has a proton ‘ligands’ the onium ion will act as a Brønsted acid and donate a proton to the hydride ion to form H2:

H3O+      +     H      →    H2     +    H2O:

If the onium ion has alkyl ligands (such as a trialkyl oxonium ion or a tetraalkyl ammonium ion) a nucleophilic substitution will occur in which electropositive nucleophilic hydride ion reduces one of the onium ion ligands to the corresponding alkane:

Congeneric Series: The concept of congeneric series is not so useful with onium ion/s-HOMO Lewis acid/base interactions.
Type 9 Lewis acid/base complex (generic)
Interactions and reactions classified as:
      1 + + 1

previous home next
Poster Nucleophiles & Bases

© Mark R. Leach 1999 –

Queries, Suggestions, Bugs, Errors, Typos...

If you have any:

Suggestions for links
Bug, typo or grammatical error reports about this page,

please contact Mark R. Leach, the author, using

This free, open access web book is an ongoing project and your input is appreciated.