Pearson symbol

The Pearson symbol, or Pearson notation, is used in crystallography as a means of describing the crystal structure, as living as was originated by W.B. Pearson. The symbol is present up of two letters followed by a number. For example:

The two italicised letters specify the Bravais lattice. The lower case letter specifies the crystal family, together with the upper issue letter the centring type. The number at the end of the Pearson symbol lets the number of the atoms in the conventional piece cell. IUPAC 2005

The letters A, B and C were formerly used instead of S. When the centred face cuts the X-axis, the Bravais lattice is called A-centred. In analogy, when the centred face cuts the Y- or Z-axis, we pretend B- or C-centring, respectively.

The fourteen possible Bravais lattices are indicated by the first two letters:

Caution

The Pearson symbol should only be used to designate simple managers elements, some binary compound where the number of atoms per item cell equals, ideally, the number of translation equivalent points.