Based on the definition of unit cell please explain why we d

Based on the definition of unit cell, please explain why we do not choose a unit cell with a base-centered tetragonal lattice. A base-centered tetragonal lattice is shown schematically on the right with a = b notequalto c, alpha = beta = gamma = 90 degree.

Solution

if u have tetragonal cell with base centering then u can choose a primitive tetragonal cell having the area corresponding to one half of the centered one.this means the centering operation does not produce something new.A completely different situation set up when centering the base of monoclinic lattice as a matter of fact if one obtains a primitive cell from the monoclinic an oblic rhombic prism is obtained.