Crystal Systems and General Chemistry B. D. Sharma California State University, Los Angeles, Los Angeles, CA 90032 and Los Angeles Pierce College, Woodland Hills, CA 91371
Crystal chemistry is a subject of great importance (1,2)and, with good reasons. some asvects of this tooic are included in chemistry. The of thi; subject invariably includes either a table or eraohics of c m t a l svswms alone with axial length and interaxial angle relatfouships. In the a&ence of svmmetrv considerations. the relationshiv of axial leneths a n d interaxial angles for each crystal system can he ;isleading. We present the definitions of each crystal system from the point of minimum symmetry inherent in each crystal system relating the packing of the chemical motif in the three-dimensional array and the consequence of the same toward the interaxial angles and axial length ratios. For detailed and precise discussion from a crystallographic point of view the reader is referred to texts on crystallography and physical chemistry ( 3 , 4 , 5 ) .
Tricllnlc System The symmetry of a triclinic system is either just onefold rotation axis or just center of symmetw. These svmmetrv elements place no restrictionson~either
