[ptryon]

I was asked a thoughtful question by a student today...

We've all seen the diagram; Diamond is a macromolecule where each carbon atom is covalently bonded to 4 other carbon atoms... but what happens at the end? Eventually we reach the surface, so what are these outermost atoms bonded to and why? Any ideas?

[jeffrey.struss]

In general they will take H from the air, as in general a carbon with a lone pair or lone electron is VERY reactive. Likely will not react with oxygen because it would want to form a carbonyl (still possible but would require breaking another one of the c-c sigma bonds). May react with water to form H on one bond and OH on another maybe, but in general it should be mainly H capped.

[ptryon]

Hi Jeffrey
Thanks for your answer. Its one of those questions the textbooks seem to miss- so when students ask it always makes me happy because they are thinking about the chemistry.
Pete

[rackye]

that's right ptryon in any case diamods have a specific geometry arrangement. This concept is similar to the unitary cell in the NaCl crystals, in anycase there is a very wide field in that kind of chemistry called surface chemistry