Problem: NaCl and KF have the same crystal structure. The only difference between the two is the distance that separates cations and anions.CompoundLattice EnergykJ/molCompoundLattice EnergykJ/molLiF1030MgCl22326LiCl834SrCl22127LiI730NaF910MgO3795NaCl788CaO3414NaBr732SrO3217NaI682KF808ScN7547KCl701KBr671CsCl657The lattice energies of NaCl and KF are given in the table in the introduction. Based on the lattice energies, would you expect the Na-Cl or the K-F distance to be longer?

FREE Expert Solution

We’re being asked to determine which distance would be longer, Na-Cl or K-F.


To estimate the lattice energy (or ionic bond energy) of an ionic compound, we will use the following equation:

lattice energy=cation charge×anion chargecation radius + anion radius

Radius = period number

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Problem Details
NaCl and KF have the same crystal structure. The only difference between the two is the distance that separates cations and anions.


CompoundLattice Energy
kJ/mol

CompoundLattice Energy
kJ/mol
LiF1030MgCl22326
LiCl834SrCl22127
LiI730

NaF910MgO3795
NaCl788CaO3414
NaBr732SrO3217
NaI682

KF808ScN7547
KCl701

KBr671

CsCl657


The lattice energies of NaCl and KF are given in the table in the introduction. Based on the lattice energies, would you expect the Na-Cl or the K-F distance to be longer?

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