Inorganic Chemistry - Semester 2

Question 1

What is the coordination number?

Answer 1

The number of donor atoms around a transitional metal.

Question 2

What are the four types of constitutional isomerism?

Answer 2

Linkage isomerism.

Coordination isomerism.

Ionisation isomerism.

Solvate isomerism.

Question 3

What is linkage isomerism?

Answer 3

Where an ambidentate ligand is connected by a different atom.

For example NO₂ and ONO.

Question 4

What is coordination isomerism?

Answer 4

Where there is an anionic and cationic transition metal complex connected, coordination isomerism is the changing of the ligands from the cation to the anion.

Question 5

What is ionisation isomerism?

Answer 5

Where a ligand in the inner sphere swaps with a ligand in the outer sphere.

Question 6

What is solvate isomerism?

Answer 6

A special type of ionisation isomerism where water is swapped between the inner and outer sphere.

Question 7

What is stereoisomerism?

Answer 7

The are the atom-atom connectivities are identical but the individual atoms are arranged differently in space.

Question 8

What are the two types of stereoisomerism?

Answer 8

Geometrical isomerism.

Optical isomerism.

Question 9

What is geometrical isomerism?

Answer 9

In square planar structures, it is in the form of cis-trans isomerism.

In octahedral complexes it can happen as cis-trans isomerism or mer-fac isomerism.

Question 10

What is mer-fac isomerism?

Answer 10

Where there are equal numbers of two types of ligands in an octahedral complex, the three ligands can form a meridonal arrangement (in a single plane) or a facial arrangement (when connected form a face of the octahedron).

Question 11

What is a hard metal?

Answer 11

A metal with a high charge density. They favour forming bonds to ligands which are small and electronegative.

The bonding between the hard metal and the hard ligand has a high degree of ionic character.

Question 12

What is a soft metal?

Answer 12

A metal with a lower charge density and is more polarisable. They form bonds with ligands that are large and polarisable.

The bonding between the soft metal and the soft ligand has a high degree of covalent character.

Question 13

Which sub-shells are filled first for neutral gaseous transition metals?

Answer 13

The 4s is filled before the 3d.

Question 14

Which sub-shells are filled first when a transition metal atom or ion is bound to ligands?

Answer 14

The 3d level fills before the 4s.

Question 15

What happens to the energy of 3d electrons when a ligand binds to it?

Answer 15

The energy increases.

Question 16

What is the 3d splitting pattern in an octahedral complex?

Answer 16

The d_xy, d_xz and the d_yz orbitals decrease in energy and form the t_2g orbitals.

The d_z² and dx²-y² orbitals increase in energy and form the eg orbitals.

Question 17

What are the values of ΔO for an octahedral splitting pattern?

Answer 17

The t_2g orbitals have a value of -0.4ΔO.

The e_g orbitals have a value of +0.6ΔO.

Question 18

What is a high spin configuration?

Answer 18

A configuration where the number of unpaired spins is maximised.

Question 19

What is a low spin configuration?

Answer 19

A configuration where the number of unpaired spins is minimised.

Question 20

What is the effect of ΔO on the high/low spin configuration?

Answer 20

A large ΔO outweighs the pairing energy and so the complex will be low spin.

A small ΔO leads to high spin complexes.

Question 21

How does the metal influence ΔO?

Answer 21

The greater the oxidation state, the greater the value of ΔO.

The further down the periodic table, the greater the value of ΔO.

Question 22

How does the ligand influence ΔO?

Answer 22

A “strong field” ligand (CN⁻, CO, PR₃, bipy) will cause a large ΔO.

A “weak field” ligand (water, hydroxide ions and halide ions) will cause a small ΔO.

Question 23

What is the splitting pattern for tetrahedral complexes?

Answer 23

The dz² and dx²-y² orbitals decrease in energy and form the e orbitals.

The dxy, dxz, dyz orbitals increase in energy and form the t₂ orbitals.

Question 24

What are the values for Δt?

Answer 24

The t₂ orbitals have a value of +0.4Δt.

The e orbitals have a value of -0.6Δt.

Question 25

How does Δt compare to Δo?

Answer 25

Δt is less than Δo.

Δt has a value of around 4/9 of Δo.

Question 26

What configurations does tetrahedral splitting form?

Answer 26

Only high spin complexes.

This is because the value of Δt are never large enough to offset the pairing energy.