# Why is cyanide writted as CN- when the negative charge is on carbon?

The Title pretty much sums it up.
http://en.wikipedia.org/wiki/Cyanide

Why is it written like that when it is clear that the carbon must be the one with the negative charge?

## Answers and Replies

Simon Bridge
Homework Helper
Convenience. It's actually [CN]-

Borek
Mentor
Charge on polyatomic molecules is almost never localized on a single atom, it is typically spread over part of the molecule. Doesn't mean there are equal parts of the charge on all atoms either, CN- has a "more negative end".

I guess this then implies to OH- as well. But how should interpret a molecular formula like that when reading it somewhere. As an overall negative molecule, or "cause I know" interpret it as a negative charge on carbon. The same goes with http://en.wikipedia.org/wiki/Hydroxide I guess then. But this is so frustrating to me now because if the negative charge is not on Oxygen why do they not just simply write it like that. The same goes with the cyanide example why do they have to write it like that when they could just have written it C-N

Borek
Mentor
It is not an obvious thing to someone just starting with chemistry that charge is not a point like thing, but a cloud spread around some volume, with different densities in different places. We start with simplified models (think Lewis structures) which require electrons to be point like, electron cloud is introduced much later.

dextercioby
Oh well, I guess Ill just deal with it, I mean I can still handle myself around it and I can still do some of the tasks and questions in the book. I understand what they mean, and I dont really wanna go to deep into this. Thanks though anyway people :)