At absolute zero, entropy is also equal to zero in a perfect one of these according to the third law of thermodynamics, and the energy required to separate one of these into a gas is its lattice energy.
Scattering in these materials is subject to the equation n theta equals two d times sine of theta, and the structure of these materials can be visualized with diagrams named for Bravais.  Each of these materials has an associated Madelung constant, and these materials are the subject of Bragg's law. At absolute zero, entropy is also equal to zero in a perfect one of these according to the third law of thermodynamics, and the energy required to separate one of these into a gas is its lattice energy. For 10 points, name these materials in which atoms or ions are arranged in a repeating three- dimensional pattern.
Scattering in these materials is subject to the equation n theta equals two d times sine of theta, and the structure of these materials can be visualized with diagrams named for Bravais.  
{Crystal}s