How many bravais lattices are present in total of seven crystal systems?

14

There are four types of unit cell

(i) Primitive (Simple): Lattice points are at corners.

(ii) Face-centred: Lattice points are at corners and at face-centres.

(iii) Body-centred: Lattice points are at corners and at body-centres.

(iv) End-face centred: Lattice points are at corners and at end-faces.

Seven types of crystal systems exist.

Total number of arrangements = 7 x 4 = 28

But only 14 of these arrangements exist, because for these arrangement of atoms, force of attraction > force of repulsion.

In rest of fourteen, repulsion > attraction.

Hence, only 14 Bravais lattices are present in 7 crystal systems.