In a hexagonal crystal :
α=β=γ≠90∘;a=b=c
α=β=γ=90∘;a=b≠c
α=β=γ=90∘;a≠b≠c
α=β=90∘,γ=120∘;a=b≠c
In Hexagonal crystal α=β=90∘,γ=120∘;a=b≠c