# Oxidation #'s in [Re2Cl9]2-

1. Apr 24, 2007

### kankerfist

Sorry about no latex, when I try using latex my formulas just wind up as a link

Anyway, I was trying to balance a redox equation and I am completely stumped
as to how:

[Re2Cl9]^2-

can be possible. I'm aware that some arrangements can cause the same atoms
in an ion to have different oxidation numbers, but I can't seem to figure out how
that molecule can exist under any arrangement. Any hints would be appreciated

2. Apr 24, 2007

### ssb

To help with latex, ive seen that message when i try to preview a post but if i actually make a post then it will show up. Sometimes I make an error in my latex and i can just edit it real fast. Just try to post some latex and not preview see if that works.

3. Apr 24, 2007

### ssb

unless you get this error then you really did something wrong
$$\LATEX$$

4. Apr 24, 2007

### kankerfist

Ok, I'll test it by quoting someone that used it sucessfully.

$$^{33}_{17}Cl^{16}\xrightarrow{n,n}~^{31}_{15}P^{16 }+~^4_2He^2$$

5. Apr 24, 2007

### ssb

There You Go. Now see if you can edit your first post with some good code!
Im looking forward to your work!

Edit: You the man

Last edited: Apr 24, 2007
6. Apr 24, 2007

### kankerfist

$${ReCl}_5} + {{H_2}O}$$
-->
$${Re_2}{Cl_9}^{2-} + {ReO_4^-} + {Cl^-} + {H^+}$$

Last edited: Apr 24, 2007
7. Apr 24, 2007

### ShawnD

It's possible for atoms to have a charge that isn't a whole number, or the number can be very different from what is expected. For example, what is carbon monoxide, CO? Does the oxygen have 4 bonds? Does the carbon have 2 bonds? Do they compromise to make 3 bonds each? (edit: I looked it up and yes they make 3 bonds each).
The number of bonds between atoms or groups of atoms is called the Bond Order.
From that link "A good example of this is bonds between carbon in the molecule benzene where the delocalized molecular orbitals contain 6 pi electrons over six carbons essentially yielding half a pi bond. Together with the sigma bond the bond order is 1.5"

Is it possible that Re has a bond order of 3.5? Sure, why not?

Last edited: Apr 24, 2007
8. Apr 24, 2007

### kankerfist

Ok, finally figured it out above. I am trying to balance this equation, and in order to break it into half reactions, I need to know the ox #'s of each atom to see which is the reduction half and which is the ox half. If the Re is 3.5 like you say, then am I on the right track that the oxidation half reaction is:
2 ReCl5 + 3e- --> $${Re_2}{Cl_9}^{2-}$$

edit: sorry, I mean reduction half

9. Apr 25, 2007

### Staff: Mentor

The best approach is to assume that oxidation numbers are just an accounting device and they don't refer to any real chemical property.