Description:
<jats:title>Abstract</jats:title><jats:p>The line groups are established as the symmetry groups of modulated crystals. The formula of the structure factor in the Fourier‐Bessel synthesis for polymers is extended to modulated crystals. The existence of translational invariance according to line groups is shown for the crystals K<jats:sub>2</jats:sub>SeO<jats:sub>4</jats:sub>and MnAu<jats:sub>2</jats:sub>.</jats:p>