Crystals

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Crystals True solids, made up of regularly repeating groups of atoms, ions, or molecules. In contrast with liquids and other amorphous materials, the properties of crystals vary with the direction in which they are measured. A complete crystal structure is defined by giving both a lattice of points, of which only 14 types are possible, and the group of atoms associated with each lattice point. The study of crystals is called crystallogaphy. >> 

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