The monoclinic crystal structure of georgbokiite, a new mineral with the chemical composition Cu₅O₂(SeO₃)₂Cl₂ (a = 6.030(1) Å), b = 13.744(3) Å, c = 5.562(1) Å, β = 95.75(1)°, V = 458.6(2) ų, Z = 2, P2₁/c) has been refined to an R index of 0.043 (wR = 0.108). The structure is similar to that previously determined for synthetic Cu₅Se₂O₈Cl₂ It is based on the unbranched zweier chains {uB, [formula omitted]} [O₂CU₅] running parallel to the c axis which are composed of [OCu₄] oxocentered copper tetrahedra linked through corners and edges in turn. The pyramidal (SeO₃) groups are in “face-to-face” positions relative to the [OCu₄] tetrahedra and together with the oxocentered chains form the more complex chains {[O₂Cu₅](SeO₃)₂} lying side by side in the (010) plane. The chloride anions are located between the chains to link them into a three-dimensional framework. The main structural features of other inorganic compounds based on single chains of oxocentered condensed copper tetrahedra are discussed in comparison.