according to Bravias lattices, a hexagonal unit cell can have only a primitive lattice. but we see the hexagonal closed pack lattice where the atoms are also at places other than corner, which is not a primitive unit cell by definition, since a primitive unit cell can have the atoms ONLY at corners, but hcp has 3 atoms in between too. then why is the hcp considered as a primitive unit cell?

according to Bravias lattices, a hexagonal unit cell can have only a p

1.	according to Bravias lattices, a hexagonal unit cell can have only a primitive lattice. but we see the hexagonal closed pack lattice where the atoms are also at places other than corner, which is not a primitive unit cell by definition, since a primitive unit cell can have the atoms ONLY at corners, but hcp has 3 atoms in between too. then why is the hcp considered as a primitive unit cell?
Answer» according to Bravias lattices, a hexagonal unit cell can have only a primitive lattice. but we see the hexagonal closed pack lattice where the atoms are also at places other than corner, which is not a primitive unit cell by definition, since a primitive unit cell can have the atoms ONLY at corners, but hcp has 3 atoms in between too. then why is the hcp considered as a primitive unit cell?