Periodic Table |
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Lewis Acid/Base Interaction Matrix Database
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Complex Anion Lewis Bases

High Symmetry Molecular Anions | ![]() Search for complex anion Lewis bases species in The Chemical Thesaurus |
FMO Topology: | Complex anion Lewis bases have a hypervalent central cation (boron, aluminium or heavy metal) saturated with anionic Lewis base ligands. Lewis octet and 18-electron rules are generally satisfied. The HOMO shows high spherical symmetry. |
Charge: | Negative. |
HSAB: | Intrinsically hard. |
Chemistry: |
Complex anion Lewis base species behave as charged hard spheres that form ionic charge-controlled complexes (ie act as non-nucleophilic counter ions), or they behave as donors of hard/soft ligands, X. Ligand substitution in which a nucleophilic Lewis Base displaces a nucleofugal ligand is common and ligand symbiosis considerations/effects are very important. There are four subclasses of complex anion Lewis base: X = Halogen anion which gives rise to the synthetically useful non-basic, non-nucleophilic, non-interfering anionic spectator counter ions:
X = Hydride ion which gives rise to species which act as donors of nucleophilic hydride ion, [BH4] and [AlH4], as long as there is not a Brønsted Acidic proton available or H2 is generated. M = Heavy metal (Fe or Cr as opposed to B or Al). Such complex anions are much studied in classical inorganic coordination chemistry. Transition metals centres often exhibit multiple oxidation states. These are better considered as type 23 Lewis acid/base complexes. X = Oxygen heavy metal species with oxygen ligands are commonly used as oxidising agents. |
Congeneric Series: |
Families of ligand replacement congeneric series are common: ![]() |
Complex anion Lewis base (generic)![]() |
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Alkoxy aluminium hydride ion (generic) more here |
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Alkoxy borohydride ion (generic) more here |
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Alkyl aluminium hydride ion (generic) more here |
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Alkyl borohydride ion (generic) more here |
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Aluminium hexafluoride ion more here |
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Aurocyanide ion more here |
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Beryllate ion more here |
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Bromine hexafluoride ion more here |
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Chlorine tetrafluoride ion more here |
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Dialkoxyaluminium hydride ion (generic) more here |
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Dialkoxyborohydride ion (generic) more here |
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Dialkylaluminium hydride ion (generic) more here |
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Dialkylborohydride ion (generic) more here |
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Dichlorosilver(I) ion more here |
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Dicyanosilver(I) ion more here |
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Germanium hexachloride dianion more here |
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Germanium hexafluoride dianion more here |
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Hexafluoroantimonate(V) more here |
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Hexafluoroarsinate ion more here |
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Hexafluoropalladium(IV) more here |
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Hexafluoroplatinate ion more here |
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Hexafluorosilicate ion more here |
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Hexahydroiron(II) ion more here |
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Iodine hexafluoride ion more here |
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Iodine octafluoride ion more here |
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Lead hexachloride dianion more here |
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Lead hexafluoride dianion more here |
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Manganate(V) ion more here |
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Manganate(VI) ion more here |
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Metaborate ion more here |
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Orthoborate ion more here |
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Pentahydrocobalt(I) ion more here |
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Perbromate ion more here |
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Perchlorate ion more here |
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Periodate ion more here |
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Permanganate ion more here |
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Perxenate ion more here |
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Phosphorus hexafluoride ion more here |
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Platinum(II) tetrachloride ion more here |
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Platinum(IV) hexachloride ion more here |
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Scandium(III) hexafluoride ion more here |
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Tetrabromoaluminate more here |
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Tetrabromoborate more here |
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Tetrabromoferrate ion more here |
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Tetrachloroaluminium ion more here |
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Tetrachloroborate more here |
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Tetrachlorocopper(I) ion more here |
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Tetrafluoroaluminate more here |
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Tetrafluoroberyllate ion more here |
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Tetrafluoroborate ion more here |
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Tetrahydroaluminate more here |
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Tetrahydroborate ion more here |
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Tetrahydrogallinate ion more here |
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Tetrahydroindate ion more here |
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Tetrahydronickel(II) ion more here |
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Tetrahydroxyaluminate ion more here |
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Tetrahydroxyborate ion more here |
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Tetrahydrozinc(II) ion more here |
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Tetraiodoaluminate more here |
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Tetraiodoborate more here |
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Tin hexachloride dianion more here |
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Tin hexafluoride dianion more here |
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Tin pentachloride ion more here |
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Trialkoxyaluminium hydride ion (generic) more here |
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Trialkoxyborohydride ion (generic) more here |
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Trialkylaluminium hydride ion (generic) more here |
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Trialkylborohydride ion (generic) more here |
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Vandate(V) ion more here |
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Xenate ion more here |
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Xenon heptafluoride ion more here |
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Xenon octafluoride ion more here |
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Zintl ion more here |
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Poster | Nucleophiles & Bases |
© Mark R. Leach 1999 –
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