Bravis lattices

In two dimensions, there are five distinct Bravais lattices, while in three dimensions there are fourteen. The lattices in two dimensions are the square lattice, the rectangular lattice, the centered rectangular lattice, the hexagonal lattice and the oblique lattice as shown in Figure. All the lattice points of the rectangular lattice can be obtained by a combination of the lattice vectors a1 and a2. The centered rectangular lattice can be constructed in two ways. It can be obtained by starting with the same lattice vectors as those of the rectangular lattice and then adding an additional atom at the center of each rectangle in the lattice.The lattice vectors a1 and a2 generate
Figure[The five Bravais lattices of two-dimensi
onal crystals: (a) square, (b) rectangular, (c)
centered rectangular, (d) hexagonal and
(e) oblique )].
the traditional unit cell and the center is obtained by attaching two lattice points to every lattice point of the traditional unit cell.