For the complex $\ce{[Fe(CN)5NO]^{2-}}$ wikipedia cites that the oxidation no. of Fe is +2 and that of NO is +1. CN being -1 the net charge thus becomes -2. However at certain places I read that NO is neutral and Fe is in its +3 oxidation state. In both cases the net charge is -2. However which of the two is correct ?
$\begingroup$
$\endgroup$
2
-
1$\begingroup$ Related: Is iron in the brown ring compound in a +1 oxidation state? $\endgroup$– Martin - マーチン ♦Commented Oct 30, 2018 at 9:18
-
$\begingroup$ The Wikipedia articles states that by epr experiment the Fe is $ d^6 $ so $\ce{Fe^{2+} }$. If NO can be formally either 0 or +1 you cannot determine which without some experimental data. $\endgroup$– porphyrinCommented Oct 31, 2018 at 10:06
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
1
The thing about nitrogen monoxide ($\ce{NO}$) is that it can be both a neutral compound and an ionic compound, depending on the context. This problem is about complex ions, which consist of a metal cation and supporting 'ligands.' Ligands are entities/molecules which bind to a metal cation to form a complex or coordinate ion.
According to this article, in $\ce{[Fe(CN)_5NO]^{-2}}$, $\ce{Fe}$ is the metal cation, and $\ce{CN^{-1}}$ and $\ce{NO}$ are the supporting ligands. Given that the ion CN has a charge of -1, that will be its oxidation number. NO is neutral, so it has no oxidation number. Putting this all together:
$\ce{Fe} + 5\cdot(-1) + 0 = -2\ \ \ \ $ - - - - - - -> $\ \ \ \ \ce{Fe} = +3$
Therefore, iron has a charge and an oxidation number of +3. ($\ce{Fe^{+3}}$)
answered Oct 30, 2018 at 4:42
-
$\begingroup$ Check signs in your equation. $\endgroup$ Commented Oct 30, 2018 at 9:52