Week 13 - d-block Metal Chemistry: Complexes

Juniata College Practice Set for Week 13 - d-block Metal Chemistry: Complexes. Created 2026 for Inorganic Chemistry using slides from Dr. Baran

For High and low spin states of d6 complexes, paramagnetic represents:

High-spin

For High and low spin states of d6 complexes, diamagnetic represents:

Low-spin

Complexes d4, d5, d6, and d7 have a spin state of:

Can be either high or low-spin

Crystal Field Theory (CFT) treats ligands as ____ and considers how they split the degeneracy (atomic/molecular orbitals having the same energy level) of the five d orbitals

Point charges

How are the d orbital shapes: dyz, dxy, dxz set?

t2g set, meaning they point between axes

How are the d orbital shapes: dz² and dx²−y² set?

eg set, meaning they point point along axes.

When applying valence bond theory to complexes, hybridized orbitals must be what? And why?

Empty, in order to be able to accept a pair of electrons from a ligand to form a sigma bond.

When applying valence bond theory to complexes, there can be a hybridization to what orbitals?

S, p, and d orbitals

Octahedral complexes have the hybridized orbital of what?

What hybrid orbitals make up an octahedral complex?

3dz^2, 3dx²−y², 4s, 4px, 4py, 4pz

Octahedral field Ligands along the axes destabilize the ___ more than the ____

Eg set; t2g set

Spectrochemical series (weak to strong field ligands) goes like?

I⁻ < Br⁻ < [NCS]⁻ < Cl⁻ < F⁻ < [OH]⁻ < [ox]²⁻ ≈ H₂O < NH₃ < en < bpy < phen < [CN]⁻ ≈ CO

Strong field ligands cause ____ Δoct and favor ____ complexes

large; low-spin

weak field ligands cause ____ Δoct and favor ____ complexes.

Small; high-spin

Define Crystal field stabilization energy (CFSE)

The extra stability gained by placing electrons in the lower t2g orbitals rather than the hypothetical degenerate set:

Tetrahedral field Ligands do not point directly at any d orbital, so the splitting is:

Smaller (Δtet = (4/9)Δoct.)

Why are tetrahedral field ligands smaller?

The orbital labels are reversed: e set (dz², dx²−y²) is now lower and t₂ set (dxy, dxz, dyz) is higher.

Because Δtet is so small, almost all tetrahedral complexes are:

High-spin

Square planar fields are derived by removing ____ from an octahedron.

The two axial ligands

In the square planar field, The dx²−y² orbital (b₁g) is dramatically destabilized and becomes the what?

LUMO. (The ordering from highest to lowest is: dx²−y² > dxy > dz² > dxz,dyz.)

Square planar geometry is especially favored for what metals and why?

d⁸ metals (Pt²⁺, Pd²⁺, Rh⁺, Ir⁺, Au³⁺, Ni²⁺ with strong-field ligands) because the large Δ makes pairing electrons in the lower four d orbitals energetically worthwhile.

Jahn-Teller distortions mean that any non-linear molecule with an orbitally degenerate ground state will spontaneously:

distort to remove that degeneracy

In octahedral complexes, Jahn-Teller distortions occur when the eg set is unequally occupied, meaning:

a high and low spinning complex

The most common result of a Jahn-Teller distortion is:

an elongated octahedron — two trans bonds lengthen

The lesser common result of a Jahn-Teller distortion is:

a compressed octahedron. Cu²⁺ (d⁹) shows the most pronounced Jahn-Teller distortion.