The Archimedean Truncated Octahedron , and Packing of Geometric Units in Cubic Crystal Structures
نویسنده
چکیده
Any cubic crystal structure can be divided into small units in the form of congruent semi-regular (Archimedean) truncated octahedra. The centers of these polyhedra can be chosen at invariant equivalent positions for most cubic space groups. The part of a 0567-7394/79/060946-07501.00 crystal structure enclosed by an Archimedean polyhedron is called a geometric unit (or unit for short); however, the boundary of the unit may be relaxed to include a whole molecule or ion in case the geometric division is not convenient. Based on the properties and arrangements of such geometric units, there is an interesting relationship among the 36 cubic space © 1979 International Union of Crystallography
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