Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Predominantly σ‐bonded metal carbonyl cations (σ‐carbonyls) are conveniently generated in the Lewis superacid SbF<jats:sub>5</jats:sub> or the conjugate Brønsted–Lewis superacid HFSbF<jats:sub>5</jats:sub>, primarily by solvolytic or reductive carbonylations. Thermally stable salts are formed with the fluoroantimonate(<jats:sc>V</jats:sc>) ions [SbF<jats:sub>6</jats:sub>]<jats:sup>−</jats:sup> and [Sb<jats:sub>2</jats:sub>F<jats:sub>11</jats:sub>]<jats:sup>−</jats:sup>. The salts are characterised by analytical, structural, spectroscopic and computational methods. Most homoleptic carbonyl cations have very regular geometries, comensurate with their d‐electron configurations: linear (d<jats:sup>10</jats:sup>), square planar (d<jats:sup>8</jats:sup>) or octahedral(d<jats:sup>6</jats:sup>). The cations with metals in oxidation states of +2 or +3 are termed “superelectrophilic”. Extended molecular structures form by significant interionic CF contacts with electrophilic carbon as acceptor. To account for all experimental observations, a conceptually simple synergetic bonding model is proposed. An outlook at anticipated future developments based on very recent results is provided.</jats:p>