The Order–Disorder (OD) Polytypism of [Cu2ZnTeO4]2+[SO4·H2O]2−

[Cu2ZnTeO4]2+[SO4·H2O]2− crystallizes as a category IV order‒disorder (OD) structure with two kinds of nonpolar layers with the formal composition [Cu2ZnTeO4]2+ and [SO4·H2O]2−, respectively. Reflection symmetry that is only valid for the [Cu2ZnTeO4]2+ layers leads to two ways of placing the [SO4·H2O]2− layers. Two of the polytypes are of a maximum degree of order (MDO1: P21/m and MDO2: Pnma). The crystal under investigation is mostly of the MDO2 polytype. Remaining positive electron density peaks in the difference Fourier maps indicate fragments of the MDO1 polytype.