symmetry elements .Symmetry operations are carried out with respect to points,lines,or planes called symmetry elements. Example: (a)An NH2 molecule has a (b)an H2O molecule has a threefold(C3)axis twofold (C2)axis. NH,has higher rotation symmetry than H,O
(b) an H2O molecule has a twofold (C2) axis. (a) An NH3 molecule has a threefold (C3) axis NH 3 has higher rotation symmetry than H2O Example: •Symmetry operations are carried out with respect to points, lines, or planes called symmetry elements. symmetry elements
Symmetry elements 3 Some of the symmetry elements of a cube, the twofold,threefold,and fourfold axes
Some of the symmetry elements of a cube, the twofold, threefold, and fourfold axes. Symmetry elements
mmetry Operation Symmetry operations are: Rotation Reflection hversion B6I6600u 012乳6AU The corresponding symmetry elements are: a line a point
Symmetry operations are: The corresponding symmetry elements are:
1)The identity (E) Operation by the identity operator leaves the molecule unchanged. All objects can be operated upon by the identity operation. Br
I F Cl Br • Operation by the identity operator leaves the molecule unchanged. • All objects can be operated upon by the identity operation. 1) The identity (E)
2)Inversion and the inversion center (i) .An object has a center of inversion,i,if it can be reflected through a center to produce an indistinguishable configuration. Centre of inversion,i A regular octahedron has a centre of inversion(i)
2) Inversion and the inversion center (i) •An object has a center of inversion, i, if it can be reflected through a center to produce an indistinguishable configuration. A regular octahedron has a centre of inversion (i)