Ppt on crystallography

How do you read point group notation?
In Schoenflies notation, point groups are denoted by a letter symbol with a subscript.
The symbols used in crystallography mean the following: C_n (for cyclic) indicates that the group has an n-fold rotation axis.
C_nh is C_n with the addition of a mirror (reflection) plane perpendicular to the axis of rotation..
What is point symmetry in crystallography?
The point symmetry, or point group, of a lattice is the group of linear mappings (symmetry operations, isometries) that map the vector lattice L onto itself.
Those geometric crystal classes to which point symmetries of lattices belong are called holohedries..

How do you read point group notation?