(iii) Graphene and monolayer Boron Nitride are both 2D hexagonal lattices. What is the basis in each case? Sketch the lattice and the primitive unit cell for both materials. (iv) A simple cubic lattice in real space with lattice constant a has unit translational vectors a1,a2,a3 and reciprocal unit lattice vectors of b1,b2,b3. Show that the reciprocal lattice is also simple cubic and determine its lattice constant. (v) Radiation of wavelength 0.076nm impinges on a Palladium crystal in a vacuum. Bragg diffraction is observed from the {222} planes at a minimum angle of 20 degrees. What is the lattice parameter of Palladium