• Ion Pair Energy teaches students about electrostatic interactions between charges and ions bereft of the confines of a crystalline structure.
• The Madelung Constant is an in-depth look at the Madelung constant for cubic crystal systems such as sodium chloride and cesium chloride. The terms of the Madelung series are linked to pictures of what they mean in the crystal structure. Statistical dynamics of the series, as well as convergence, is also presented.
• Lattice Energy links the first two sections. It combines the Madelung constant with the energy calculations introduced in the Ion Pair Energy section to teach students how lattice energies are calculated.
• Summary is a brief overview of what was covered in the previous three parts.
• Credits acknowledges people and references.

A screen from the Madelung Constant section of Lattice Energetics.

Lattice Energetics teaches fundamental concepts about electrostatic energies as well as in-depth concepts about the Madelung constants for certain cubic crystal structures. Features of this software include:

• Interactive pictures that show the Madelung series and its implications about what is happening in the structure.
• Interactive graphs demonstrating the relationship between terms of the Madelung series and the calculated Madelung constant, as well as terms and charge of the ion cluster being considered.
• Animations that show fractional occupation of ions within a unit cell.
• Plots of lattice energies and electrostatic interactions, as well as their relationship to charge, bond length, Born exponent, etc. (Data have been taken from several sources (1–4).)

Lattice Energetics can be used to present the concepts of lattice energetics to a class. It can also be made available for students to explore on an individual basis to help them learn about lattice energetics and the Madelung constant.

Literature Cited

1. CRC Handbook of Chemistry and Physics, 63rd edition; CRC Press: Boca Raton, Florida, 1982; pp D-52–D-95.
2. NIST Chemistry WebBook, NIST (Standard Reference Database Number 69–November 1998 Release), (accessed Nov 2002).
3. Masterton, W. L.; Hurley, C. N. Chemistry: Principles and Reactions; Saunders College Publishing: New York, 1989.
4. West, A. R. Solid State Chemistry and its Applications; John Wiley and Sons Ltd.: New York, 1984.