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Lattice Energy (Born-Lande) Calculator

Energy to form crystal lattice from gaseous ions.

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Lattice Energy Est

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Overview

Lattice energy measures the strength of the electrostatic forces within an ionic crystal, representing the energy released when gaseous ions form a solid lattice. It is a fundamental thermodynamic quantity that scales directly with the product of ionic charges and inversely with the distance between the ion centers.

Symbols

Variables

E = Lattice Energy Est, k = Constant, Q^+ = Cation Charge, Q^- = Anion Charge, d = Ionic Distance

Lattice Energy Est
kJ/mol
Constant
Variable
Cation Charge
Variable
Anion Charge
Variable
Ionic Distance
nm

Apply it well

When To Use

When to use: Use this relationship to compare the relative stabilities of different ionic salts or to predict trends in melting points and solubility. It is most applicable to compounds with predominantly ionic character where the ions can be treated as point charges in a structured arrangement.

Why it matters: Understanding lattice energy allows scientists to explain why certain substances, like magnesium oxide, have extremely high melting points compared to others like sodium chloride. It is essential for constructing Born-Haber cycles to calculate enthalpies that cannot be measured directly in a laboratory.

Avoid these traps

Common Mistakes

  • Forgetting both charge and size affect lattice energy.
  • Confusing lattice energy sign convention.

One free problem

Practice Problem

An ionic compound consists of a monovalent cation (Q1=1) and a monovalent anion (Q2=1). If the proportionality constant k is 1200 and the interionic distance d is 2.5 units, calculate the lattice energy (E).

Constant1200
Cation Charge1
Anion Charge1
Ionic Distance2.5 nm

Solve for:

Hint: Multiply the constant by the product of the charges, then divide by the distance.

The full worked solution stays in the interactive walkthrough.

References

Sources

  1. Atkins' Physical Chemistry
  2. IUPAC Gold Book: Lattice energy (enthalpy)
  3. Wikipedia: Lattice energy
  4. IUPAC Gold Book
  5. NIST CODATA
  6. Atkins' Physical Chemistry, 11th Edition, Oxford University Press
  7. Shriver & Atkins' Inorganic Chemistry, 6th Edition, W. H. Freeman and Company
  8. IUPAC Gold Book (Compendium of Chemical Terminology), 'lattice energy' entry