AbstractColourless single crystals of three piperazine (Pip) complexes of divalent mercury with ‐CF3 and SCN‐ as the ligands have been obtained from aqueous and ethanolic solution of the respective components Hg(CF3)2, Hg(SCN)2, and piperazine. The crystal structures were determined by single crystal X‐ray diffraction: Hg(CF3)2(Pip) (1) [monoclinic, C2/c, Z = 4, a = 891.2(1), b = 1649.8(2), c = 777.7(1) pm, β = 101.27(2)°, R1(all) = 0.0413], Hg(SCN)2(Pip) (2) tetragonal, P42/ncm, Z = 4, a = 840.8(1), c = 1511.0(1) pm, R1(all) = 0.0479], (Hg(SCN)2)2(Pip) (3) [triclinic, ${\rm P}{\bar 1}$, Z = 1, a = 590.6(1), b = 738.6(2), c = 919.5(2) pm, α = 88.96(2)°, β = 82.80(2)°, γ = 78.21(2)°, R1(all) = 0.0582]. In 1 and 2 zig‐zag chains are observed with the piperazine molecule only weakly attached to the Hg(CF3)2 molecule. The Hg(SCN)2(Pip) chains in 2 condense to double chains in 3 where half of the piperazine molecules are missing. In both, 2 and 3, Hg2+ is coordinated in a distorted tetragonal fashion by two N and two S ligator atoms from piperazine and SCN‐ ligands, respectively.