Indicate the coordination number and the oxidation number of...

Indicate the coordination number and the oxidation number of the metal for each of the following complexes: (a) $\mathrm{K}_{2} \mathrm{PtCl}_{4}$ (b) $\left[\mathrm{Ni}(\mathrm{CO})_{4}\right] \mathrm{Br}_{2}$ (c) $\mathrm{OsO}_{4}$ (d) $\left[\mathrm{Mn}(\mathrm{en})_{3}\right]\left(\mathrm{NO}_{3}\right)_{2}$ (e) $\left[\mathrm{Cr}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{3}$ (f) $\left[\mathrm{Zn}(\mathrm{bipy})_{2}\right]\left(\mathrm{ClO}_{4}\right)_{2}$

Indicate the coordination number and the oxidation number of the metal for each of the following complexes:
(a) $\mathrm{K}_{2} \mathrm{PtCl}_{4}$
(b) $\left[\mathrm{Ni}(\mathrm{CO})_{4}\right] \mathrm{Br}_{2}$
(c) $\mathrm{OsO}_{4}$
(d) $\left[\mathrm{Mn}(\mathrm{en})_{3}\right]\left(\mathrm{NO}_{3}\right)_{2}$
(e) $\left[\mathrm{Cr}(\mathrm{en})\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}_{3}$
(f) $\left[\mathrm{Zn}(\mathrm{bipy})_{2}\right]\left(\mathrm{ClO}_{4}\right)_{2}$

Key Concepts

Charge Balance and Counter Ions

Charge balance in coordination complexes involves accounting for the charges on the central metal ion, the coordinated ligands, and any counter ions present in the formula. Correctly balancing these charges is fundamental in deciphering the oxidation state of the metal and the stoichiometry of the complex.

Ligands and Their Denticity

Ligands are atoms, ions, or molecules that donate a pair of electrons to the central metal ion to form a coordinate covalent bond. Their denticity, which refers to the number of donor atoms they contribute, influences the coordination number and the stability of the complex. Monodentate, bidentate, and polydentate classifications affect the overall structure and binding mode of the complex.

Coordination Number

The coordination number is the number of donor atoms through which ligands attach themselves to the central metal ion in a coordination complex. It is essential for determining the geometric structure of the complex and can be influenced by the size, electronic configuration of the metal, and the steric properties of the ligands.

Oxidation State of the Metal

The oxidation state of a metal in a coordination complex is the formal charge it would possess if all bonds to the ligands were considered completely ionic. This value is determined by considering the known charges on the ligands and any counter ions, and it is critical for understanding the redox behavior, reactivity, and electronic configuration of the metal center.

Transcript

00:04 We are asked to examine six different formula for compounds for metal complexes and give the coordination number and the oxidation number for each.

00:17 Let's get started with a.

00:21 I'll write the formula and then we'll talk about them.

00:28 Coordination number, i'm going to abbreviate cn.

00:31 Oxidation number, i'm going to abbreviate o .n.

00:36 For this substance, our oxidation number for a potassium, excuse me for a platinum will be 2 plus and that is because we have negative 4 that's contributed to the charge from the chlorine 2 plus from the potassium and i have to have 2 plus here my oxidation number will be 4 because i've got 4 chlorines that are acting as my ligands on here our second substance is as follows for this substance, our oxidation number for the nickel is going to be 2 plus.

01:40 And that's because this is a neutral ligand.

01:42 We've got negative 1 charge times 2.

01:45 It's 2 minus.

01:46 This needs to be a 2 plus.

01:51 For my coordination number, that will be 4.

02:07 Make sure i wrote this one down right.

02:09 Ni, co4, b2.

02:14 So the co is a monodentate, so i will have a coordination number of 4.

02:24 Okay, got it.

02:25 And next, let's do c.

02:32 The oxidation number for this will be 8 plus, because each of these is negative 2 for 8 minus, and this therefore has to be 8 plus.

02:48 My coordination number, again, will be 4.