Point Group For The students

1. Point Group For The students

Karimat EL-Sayed
Physics Department , Faculty of
Science , Ain-Shams University

2. Symmetry Elements

• We may have the following combinations:
–
–
–
–
–
–
–
X
X
X/m
Xm
Xm
X2
X/mm
rotation axis alone
inversion axis alone
rotation axis normal to a plane of symmetry
rotation axis with a vertical plane of symmetry
inversion axis with a vertical plane of symmetry
rotation axis with a diad axis normal to it
rotation axis with both kinds of plane symmetry

3. Space Group

4. SCREW AXIS

5.

6. Glide Plane

7. The point and monoclinic space group

8.

9.

10.

11.

12. Class m; the crystallographic axes, showing their relationship to the plane of symmetry, and a stereogram of the general form

13.

14. Orthorhombic Class mm

15.

A crystal of
potassium tetrathionate
A crystal of
Na2SiO2.5H2O
A crystal of
hilgardite

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33. Pritsm

34.

35.

36.

37. Different combination of The Cubic Point group

38.

39.

40.

41.

42. Class 432 the elements of symmetry, crystallographic axes and a stereogram of the general form

43. Class m3m; the elements of symmetry, crystallographic axes and a stereogram of the general form