HW 2 Inorganic Materials
Chemistry
Name:
Points: C7780 Date:
Max. 100 points Fall 2019 A
1. (10 pts) Copper metal crystallizes with a cubic close packed (ccp or fcc) structure having a
lattice parameter a = 3.6147 Å. Calculate the Cu-Cu distance (separation) between nearestneighbor
Cu atoms in the crystal. Hint: nearest-neighbor Cu atoms are any two within the same
close-packed layer (plane).
2. (10 pts) Molybdenum metal crystallizes with a body-centered cubic (bcc) structure having a
lattice parameter a = 3.1469 Å. Calculate the Mo-Mo distance (separation) between nearestneighbor
Mo atoms in the crystal. Hint: the nearest-neighbor atoms are aligned along the body
diagonal of the bcc unit cell.
3. (20 pts) Derive the first three terms of the series to calculate the Madelung constant for CsCl.
Use interionic separation d (d = rCs+ + rCl) as the distance parameter in the Coulomb equation.
4. (10 pts) Should it be possible to convert -cristobalite to some of the other modifications by
applying high pressure?
Modification of SiO2 Density / g cm1
-quartz 2.65
-quartz 2.53
-tridymite 2.27
-cristobalite 2.33
Vitreous 2.20
5. (15 pts) a) Write balanced chemical equation for a solid state reaction:
ZnC2O4 + Fe(OH)3  ZnFe2O4
b) What is the driving force in this reaction?
c) Cubic spinel ZnFe2O4 crystallizes with 8 formula units in the cubic unit cell. The cell parameter
a = 8.42 Ǻ. Calculate the density in g cm3
of the material.
NA = 6.022141 1023
mol1
, Ar(Zn) = 65.41, Ar(Fe) = 55.85, Ar(O) = 15.999.
6. (15 pts) The cell parameter for cubic spinel ZnFe2O4 is a = 8.42 Ǻ, for MnFe2O4 a = 8.50 Ǻ.
a) Suggest a reason for the difference.
b) What would be the cell parameter for the mixed-metal phase (MnxZn1x)Fe2O4 when x = 0.25,
0.50, and 0.75.
7. (20 pts) Assume that CaO reacts with CeO2 and forms CaCeO3.
a) What could be the structure type of this compound? ______________
b) Write balanced chemical equations for the reactions taking place at the interface I and II
(assume counter diffusion of both cations) and calculate the Kirkendall ratio for this process.
I II
CaO CaCeO3 CeO2