A one-dimensional ladder-like six-coordinate cadmium polymer: catena-poly[bis[(S)-2-methylpiperazine-1,4-diium] [bis[trichloridocadmium(II)]-di-μ3-chlorido]].

The crystal structure of the title compound {(C5H14N2)2[Cd2Cl8]}n, (I), consists of hydrogen-bonded 2-methylpiperazinediium (H2MPPA(2+)) cations in the presence of one-dimensional polymeric {[CdCl3(μ3-Cl)](2-)}n anions. The Cd(II) centres are hexacoordinated by three terminal chlorides and three bridging chlorides and have a slightly distorted octahedral CdCl3(μ3-Cl)3 arrangement. The alternating CdCl6 octahedra form four-membered Cd2Cl2 rings by the sharing of neighbouring Cd-Cl edges to give rise to extended one-dimensional ladder-like chains parallel to the b axis, with a Cd···Cd distance of 4.094 (2) Å and a Cd···Cd···Cd angle of 91.264 (8)°. The H2MPPA(2+) cations crosslink the [CdCl3(μ3-Cl)]n chains by the formation of two N-H···Cl hydrogen bonds to each chain, giving rise to one-dimensional ladder-like H2MPPA(2+)-Cl2 hydrogen-bonded chains [graph set R4(2)(14)]. The [CdCl3(μ3-Cl)]n chains are interwoven with the H2MPPA(2+)-Cl2 hydrogen-bonded chains, giving rise to a three-dimensional supramolecular network.