Noun
point group (plural point groups)
(mathematics) A group of isometries leaving a fixed point.
For example, halite (NaCl), galena (PbS), and periclase (MgO) all belong to the hexaoctahedral point group (isometric family), as they have a similar stoichiometry between their different constituent elements. Source: Internet
Point groups The crystallographic point group or crystal class is the mathematical group comprising the symmetry operations that leave at least one point unmoved and that leave the appearance of the crystal structure unchanged. Source: Internet
Kyanite is triclinic, while andalusite and sillimanite are both orthorhombic and belong to the dipyramidal point group. Source: Internet
Space groups In addition to the operations of the point group, the space group of the crystal structure contains translational symmetry operations. Source: Internet
In order to assign a point group for any given molecule, it is necessary to find the set of symmetry operations present on it. Source: Internet
The general procedure for constructing a molecular orbital diagram for a reasonably simple molecule can be summarized as follows: 1. Assign a point group to the molecule. Source: Internet