## The Book of Crystallography

An lattice, and its Fourier Transform:

The grid points (delta functions) are exaggerated for clarity. Note
that the Fourier transform of a grid is a grid with reciprocal
*directions* and *spacings*. This is the origin of the
reciprocal lattice.

A crystal, and its Fourier Transform:

Finally, we build up a crystal by convoluting the *molecule*
with the *grid*. The result is a crystal structure. The Fourier
transform of the crystal is thus the product of the *molecular
transform* and the *reciprocal lattice*. This is the
*diffraction pattern*.

More Fourier transforms.
Back to the index.