The Born–Mayer equation is an equation that is used to calculate the lattice energy of a crystalline ionic compound. It is a refinement of the Born–Landé equation by using an improved repulsion term.
- NA = Avogadro constant;
- M = Madelung constant, relating to the geometry of the crystal;
- z+ = charge number of cation
- z− = charge number of anion
- e = elementary charge, 1.6022×10−19 C
- ε0 = permittivity of free space
- 4πε0 = 1.112×10−10 C2/(J·m)
- r0 = distance to closest ion
- ρ = a constant dependent on the compressibility of the crystal; 30 pm works well for all alkali metal halides
- "Lattice Energy" (PDF).