HW 1 Inorganic Materials
Chemistry
Name:
Points: C7780 Date:
Max. 100 points Fall 2013 A
1. (5 pts) A unit cell have in general shape of a) cube b) tetrahedron c) parallelepiped
2. (35 pts) Assume that CaO reacts with CeO2 and forms CaCeO3. What could be the structure
type of this compound? ______________
Write balanced chemical equations for the reactions taking place at the interfaces I and II
(assume counter diffusion of both cations) and calculate the Kirkendall ratio for this process.
I II
3. (10 pts) Derive Miller indices for planes that intersects the cell axes at a/2, 2b/3, 2c.
4. (15 pts) Give stoichiometric formulas for the structures. Large atoms = A, small atoms = B
5. (15 pts) Specific surface area of α-Fe2O3 was measured by nitrogen adsorption at 77 K and
its value is 120 m2
g1
. Density of this oxide is 5.277 g cm3
. Calculate the particle size
assuming a spherical particle shape.
6. (20 pts) Maghemite γ-Fe2O3 crystallizes in a defect inverse spinel structure (as Fe3O4), but
some positions of Fe3+
in octahedral holes must be vacant, in order to maintain stoichiometry.
What part of these holes must be empty in comparison with Fe3O4.
= vacancy, empty hole, (X) = tetrahedral position, [Y] = octahedral position
Fill stoichiometric coefficients at the horizontal lines:
(Fe)___ [Fe___, ____] O4
CaO CaCeO3 CeO2