What's the deal with CO?

[xooll]

From my high-school-chemistry-six-years-ago understanding of it, a carbon atom is capable of forming four covalent bonds. An oxygen atom can do two.
So carbon dioxide works fine, but how does carbon monoxide work?

[Keith]

They can both form 4 covalent bonds. IIRC, CO has a sigma bond, 2 pi bonds and a lone pair on each atom. Sharing of the electrons isn't dependent on where the electrons come from, that only makes it coordinate covalent or not.

[Xial]

Also, although Carbon is capable of forming 4 covalent bonds, quadruple bonds do not exist.

[skeptical scientist]

All I know is that atomic bonding isn't nearly as simple as you were taught in high school. They gloss over the pathological and nonstandard cases, which do exist.

[gmalivuk]

All I know is that atomic bonding isn't nearly as simple as you were taught in high school. They gloss over the pathological and nonstandard cases, which do exist.

Like xenon pentafluoride.

Anyway, Wikipedia is, as always, a good place to start.

[Peripatetic]

And sulfur hexafluoride

[gmalivuk]

Right. I remember hearing about that but had forgotten what the chemical was.