All books

Professional

Apps About Coach Log in Start reading

Chemistry · Glossary

What is Lattice enthalpy?

Definition 1.17 University Chemistry — Year 2 · Chapter 1 — Enthalpies of Reaction

The lattice enthalpy of an ionic crystal is the standard reaction enthalpy of its dissociation into gaseous ions: for sodium chloride, NaCl(s)→NaX+(g)+ClX−(g)\ce{NaCl(s) -> Na+(g) + Cl-(g)}. It is positive, and measures the cohesion of the crystal.

The Born–Haber cycle of sodium chloride at 298\, K (kJ/ mol). Going up from the crystal to the gaseous ions by the lattice enthalpy, or round by the elements, leads to the same level: the lattice enthalpy is the only unknown of the cycle.
The Born–Haber cycle of sodium chloride at 298 K298\,\mathrm{K} (kJ/mol\mathrm{kJ}/\mathrm{mol}). Going up from the crystal to the gaseous ions by the lattice enthalpy, or round by the elements, leads to the same level: the lattice enthalpy is the only unknown of the cycle.
Read in context →

Related terms