Lattice Energy Comparison: Al2O3 vs. AlF3 - Exploring the Differences

[jsmith613]

will the lattice energy of Al₂O₃ be greater than the lattice energy of AlF₃. If so, why? If not, why?

 

[Borek]

Think about Coulomb attraction and charges.

 

[MysticDude]

The basic rules of lattice energy that I've been taught are that the lattice energy is greater if the charges of the atoms are larger and if the atomic radii are smaller. I haven't done this with two or more of the same atoms (like how there are two Al and 3 O) yet so I don't know how much of a difference that makes. Hope I was able to help in a way.

 

[lightarrow]

The basic rules of lattice energy that I've been taught are that the lattice energy is greater if the charges of the atoms are larger and if the atomic radii are smaller. I haven't done this with two or more of the same atoms (like how there are two Al and 3 O) yet so I don't know how much of a difference that makes. Hope I was able to help in a way.

What you say, assuming Al₂O₃ is totally ionic. Is it? Furtermore, in the ionic case, you also have to consider the kind of packing of ions.

 

[LudusRex]

The lattice energy of Al2O3 will be greater than the lattice energy of AlF3. This is because lattice energy is a measure of the strength of the ionic bonds in a crystal lattice, and Al2O3 has a higher charge density and a smaller ionic radius compared to AlF3.

Al2O3 has a 3+ charge on the Al ion and a 2- charge on the O ion, resulting in a stronger ionic bond compared to AlF3 which has a 3+ charge on the Al ion and a 1- charge on the F ion. Additionally, the ionic radius of O is smaller than that of F, making the Al-O bond shorter and stronger than the Al-F bond.

Furthermore, the lattice energy is inversely proportional to the distance between the ions in the crystal lattice. Since Al2O3 has a smaller ionic radius, the Al and O ions are closer together, resulting in a higher lattice energy.

In summary, the higher charge density and smaller ionic radius of Al2O3 contribute to a stronger ionic bond and a shorter distance between ions, resulting in a higher lattice energy compared to AlF3.