User:Benjah-bmm27/HCO+

Formyl cation, [HCO]⁺. Abundant in space, intermediate in the Gattermann-Koch reaction^[1]. Can generate from formyl fluoride and antimony pentafluoride:^[2]

HC(O)F + SbF₅ → [HCO]⁺ + [SbF₆]⁻

Can consider as protonated carbon monoxide (H⁺ + CO → HCO⁺), or formaldehyde from which a hydride ion has been abstracted (H₂CO → H⁻ + HCO⁺).

Structure[edit]

Resonance structures of the formyl cation, HCO+


X ¹Σ⁺ state, MW, 2008^[3]	configuration interaction, 1976^[4]	Spartan HF 6-31G*

Sortable table
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?

Refs[edit]

^ J. Org. Chem. (1995) 60, 3846–3850
^ J. Phys. Chem. B (2001) 105, 8212–8219
^ ^a ^b J. Chem. Phys. (2008) 129, 164311
^ Astrophys. J. (1976) 205, L97-L100
^ ^a ^b ^c Lide, David R. (2008). CRC Handbook of Chemistry and Physics, 89th Edition. CRC Press. p. 9-36. ISBN 978-0849304880.

[1] J. Org. Chem. (1995) 60, 3846–3850

[2] J. Phys. Chem. B (2001) 105, 8212–8219

[JCP2008-3] J. Chem. Phys. (2008) 129, 164311

[4] Astrophys. J. (1976) 205, L97-L100

[CRC-5] Lide, David R. (2008). CRC Handbook of Chemistry and Physics, 89th Edition. CRC Press. p. 9-36. ISBN 978-0849304880.

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