I came across this question where there is a FCC lattice. It states that the lattice is a convolution of the simple cubic (whose reciprocal lattice is itself) with a basis (that consists of 2 points). When finding the reciprocal of this BCC lattice, FourierTransform(BCC) = FourierTransform(SimpleCubic * Basis) = FourierTransform(SimpleCubic) . FourierTransform(Basis) Now what is the fourier transform of the basis which consists of 2 points? Thanks for any help to clear up this confusion!