NaCl and KF have the same crystal structure. The only difference between the two is the distance that separates cations and anions.
(a) The lattice energies of NaCl and KF are given in Table. Based on the lattice energies, would you expect the Na-Cl or the K-F distance to be longer?
(b) Use the ionic radii given in Figure to estimate the Na-Cl and K-F distances. Does this estimate agree with the prediction you made based on the lattice energies?
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TABLE 8.2
|
- Lattice Energies
Lattice Energy fld/rnol)
|
for Some Ionic Compound
|
Compounds
Lattice Energy (10/mol)
|
|
Compound
|
|
LiF
|
1030
|
MgCJ2
|
2326
|
|
LiCI
|
834
|
Sick
|
2127
|
|
Lil
|
730
|
|
|
|
VF
|
910
|
MgO
|
3795
|
|
Na(]
|
788
|
CaO
|
3114
|
|
NaBr
|
732
|
Sr0
|
3217
|
|
Nal
|
682
|
|
|
|
ICE
|
808
|
ScN
|
7547
|
|
KCI
|
701
|
|
|
|
KBr
|
671
|
|
|
|
CACI
|
657
|
|
|
|
Cs1
|
600
|
|
|
|
|
|
|
|
