Which one has more lattice energy, Na3N or NaF ?

Which one has more lattice energy, Na₃N or NaF ?

In case of Na₃F and NaF molecules, cations are same but anions are different [ N^3-, F^– ] .It is experimentally proved that the radius of N^3– ions is greater than F^– ion.

Now, lattice energy is directly proportional to the multiple of ionic charge and inversely proportional to the radius of cation and anion.

So, the lattice energy of  NaF should be greater than that of Na₃N compound. But, actually the order of lattice energy of NaF and Na₃N compound is reversed.

Because, in calculation of lattice energy of ionic compounds , the extent of ionic charge is more effective than ionic radius.

Since the ionic charge of N^3-ion is greater than F^–, hence Na₃N compound has high lattice energy than NaF .

The value of lattice energy of Na₃N is –4422 kj/mole and that of NaF is –923 Kj/mole.

        Read more: Which one has higher lattice energy, MgF2,CaF2 or ZrO2 ?

        Read more : Lattice energy calculation for ZrO₂ molecule

Calculation of lattice energy of Na₃N compound 

Lattice energy of Na₃N compound can be calculated indirectly by applying Born-Haber cycle. The Born-Haber cycle of Na₃N compound is shown below.

According to the Born-Haber cycle of Na₃N compound, we can write a relation among  enthalpy of formation of Na3N,electron affinity and bond dissociation of nitrogen, ionization energy and sublimation energy of sodium and lattice energy released are, 

                  ΔH_f   =  S  + [3 x I.E] + [ I.E₁ + I.E₂ + I.E₃ ] + ½ D + U

           Or,    - 20  = 322  + 1488  +  2120  +  472  + U

            Or,   U =  – 4422 Kj/mole

Therefore, the lattice energy of Na₃N compound is –4422 kJ/mole.

Which has more lattice energy, NaCl or NaF ?

In case of NaCl and NaF molecules, cations are same but anions are different [ Cl^–, F^– ] .The radius of halide ions increase from top to bottom along a group.

From the experimental data we know that the radius of chloride [ Cl^– ] ion is greater than fluoride ion [ F^–] .

Now, lattice energy is directly proportional to the multiple of ionic charge and inversely proportional to the radius of cation and anion.

Consequently, LiF has highest lattice energy. The value of lattice energy of NaCl and NaF molecules are, –785 kJ/mole and –923 Kj/mole respectively.  

Which one has more lattice energy, Na₃N or NaF ?

Which has more lattice energy, NaCl or NaF ?

Calculation of lattice energy of Na₃N compound.

                    Read more: Which one has higher lattice energy, MgF2, CaF2 or ZrO2 ?

                    Read more: Why is the lattice energy of ZrO2 sohigh ?