Lattice Energy Calculator

Estimate lattice energy (Kapustinskii equation).

Lattice energy (kJ/mol) 762.14

Formula: U = 120200 · (n·z₊·z₋ ÷ r) · (1 − 34.5/r)

Step-by-step with your numbers:

1. Values used:

2. Number of ions in formula = 2

3. Cation charge = 1

4. Anion charge = 1

5. Sum of ionic radii = 276 pm

7. Lattice energy = 762.14kJ/mol

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Estimate the lattice energy of an ionic solid with the Kapustinskii equation.

The math behind it

U (kJ/mol) = 120200 × (ions × |z₊| × |z₋| ÷ r) × (1 − 34.5/r), with r the sum of ionic radii in pm.

NaCl (2 ions, 1+/1−, r 276 pm) → ~770 kJ/mol.

Higher U?

Smaller, higher-charged ions give stronger lattices.