ANORTHIC SYSTEM (Triclinic.) In the anorthic (from av, privative, and opOos, right) or triclinic system none of the three crystallographic axes are at right angles, and they are all of unequal lengths. In addition to the parameters a : b : c, it is necessary to know the angles, a, 0, and y, between the axes. In anorthite, for example, these elements are a : b : c= ; a=93° 13', 0=115° 55',7=91° 12'.