An Etymological Dictionary of Astronomy and Astrophysics
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One of seven possible basic crystal types that is defined by the relations between the axis lengths and angles of its unit cell. Crystal systems can produce an infinite → lattice by successive translations in three-dimensional space so that each lattice point has an identical environment. The seven crystal systems are: → cubic, → orthorhombic, tetragonal, trigonal, hexagonal, monoclinic, and triclinic.

→ crystal; → system.

A → crystal system whose three axes have equal lengths and all corners are 90°.

→ cubic; → crystal; → system.

A → crystal system that has three mutually perpendicular axes, each of which is of a different length than the others.

→ orthorhombic; → crystal; → system.