Symmetry groups {tetragonal symmetry group} can have rotation by 90 degrees. Crystals {tetragonal crystal} can have one four-fold axis and three perpendicular axes but only two with same length, to make seven crystal classes.
Physical Sciences>Chemistry>Inorganic>Phase>Phases>Solid>Crystal>Symmetry
5-Chemistry-Inorganic-Phase-Phases-Solid-Crystal-Symmetry
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Date Modified: 2022.0224