Formyl cation, [HCO]+. Abundant in space, intermediate in the Gattermann-Koch reaction [1]. Can generate from formyl fluoride and antimony pentafluoride: [2]
Can consider as protonated carbon monoxide (H+ + CO → HCO+), or formaldehyde from which a hydride ion has been abstracted (H2CO → H− + HCO+).
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Species | Formula | CO bond order | r(C-O) / Å | r(C-H) / Å | technique | ref |
---|---|---|---|---|---|---|
carbon monoxide | CO | 3 | 1.128 | - | ? | G&E |
formyl cation | HCO+ | 3 | 1.1107 | 1.0933 | MW | [3] |
formyl radical | HCO | 2 | 1.1712 | 1.1110 | MW | [5] |
formaldehyde | H2CO | 2 | 1.209 | 1.116 | MW | [5] |
methanol | H3COH | 1 | 1.4246 | 1.0936 | MW | [5] |
Problem: bond lengths indicate C-O triple bond, but Lewis structure with C-O triple bond has wrong charges: +ve O and H, neutral C, whereas HF indicates neutral O, +ve C and H. Not just a simple matter of superimposing Lewis structures' wavefunctions - or is it?
Formyl cation, [HCO]+. Abundant in space, intermediate in the Gattermann-Koch reaction [1]. Can generate from formyl fluoride and antimony pentafluoride: [2]
Can consider as protonated carbon monoxide (H+ + CO → HCO+), or formaldehyde from which a hydride ion has been abstracted (H2CO → H− + HCO+).
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Species | Formula | CO bond order | r(C-O) / Å | r(C-H) / Å | technique | ref |
---|---|---|---|---|---|---|
carbon monoxide | CO | 3 | 1.128 | - | ? | G&E |
formyl cation | HCO+ | 3 | 1.1107 | 1.0933 | MW | [3] |
formyl radical | HCO | 2 | 1.1712 | 1.1110 | MW | [5] |
formaldehyde | H2CO | 2 | 1.209 | 1.116 | MW | [5] |
methanol | H3COH | 1 | 1.4246 | 1.0936 | MW | [5] |
Problem: bond lengths indicate C-O triple bond, but Lewis structure with C-O triple bond has wrong charges: +ve O and H, neutral C, whereas HF indicates neutral O, +ve C and H. Not just a simple matter of superimposing Lewis structures' wavefunctions - or is it?