K3CeCN6 what is the oxidation state of Cr

Question

K3CeCN6

what is the oxidation state of Cr

what's the electron configuration

the complex ion has numerous linkage isomers, draw 2 examples

the complex ion is a low spin, how would i draw the orbital occupation diagram for the d electrons of Cr

Answer 1

I am assuming you are referring to K₃[Cr(CN)₆]. Here you will assign the Potassium an oxidation of +1 as it is alkali metal. CN- or cyanide has a -1 charge as this is a polyatomic ion. When we account for the subscripts to find the oxidation of Cr, we see that +3 + x - 6 = 0. This gives Cr an oxidation state of +3. The electron configuration is [Ar]3d³. I am not able to provide a picture here but for the complex ion isomers, draw one isomer bound to the Carbon in Cyanide and one bound to Nitrogen. The low spin state has to do with Hund's rule where electrons occupy the lowest energy levels before having paired electrons (I call it the half-fill rule). For this example, the diagram would have ↑ ↑ ↑ in 3 of the separate d orbitals. Hope this helps.