HW 3 Inorganic Materials
Chemistry
Name:
Points: C7780 Date due:
Max. 100 points Fall 2022
1. (15 pts) In the manganese(II) oxide, the Mn2+
ions occupy the octahedral holes in the cubic
close packed structure of oxides.
a) Describe the splitting of the d-orbitals and assign symmetry labels (draw energy level
diagram).
b) Assuming the oxide ligand to be a weak field ligand, populate the d-orbitals with electrons.
c) The total spin of the Mn2+
is _________ and its multiplicity is_________.
2. (15 pts) The unit cell for a hexagonal close-packed (hcp) metal is shown below.
a) Label atom layers A, B or C to identify the close-packed layers they belong to.
b) How many lattice points Z contain this unit cell? Show your work.
3. (15 pts) Zeolite A (LTA) displays a single peak in the 29
Si MAS NMR spectrum at 89 ppm
and has a Si/Al ratio of 1. Explain these observations.
4. (15 pts) Zeolite A (Ca form), when loaded with platinum, has been found to be a good catalyst
for the oxidation of hydrocarbon mixture. If the mixture contains branched chain hydrocarbons,
these do not react. Describe a possible reason to explain these observations.
5. (40 pts) Calculate the wall thickness of a hexagonal MCM-41 mesoporous material, assume
that it possesses cylindrical pores.
a) First, calculate the d(100) = interplanar distance in the (100) plane from the XRD
diffractogram. CuK radiation was used with  = 1.542 Å. Diffraction maximum was found at
2.14 °2.
b) Now, derive the formula relating the interplanar distance d(100) to the hexagonal mesoporous
parameter a0 and calculate its value.
c) Derive the formula relating the diameter Dp of a pore to specific surface area SA (870 m2
/g)
and total pore volume Vp (0.683 cm3
/g). Assume cylindrical pores.
d) Finally, calculate the wall thickness (wt) of MCM41 material.