Synthesis and structure of [NMe4][CuPt(CN)4]: an infinite three-dimensional framework related to PtS which generates intersecting hexagonal channels of large cross section

[NMe4][CuPt(CN)4] contains an infinite 3D [CuIPtII(CN)4]nn– framework related to the PtS structure, which generates two mutually perpendicular and equivalent sets of hexagonal channels of large cross-section (largest Pt ⋯ Pt diagonal, 13.50 Å) together with large empty square channels perpendicular to the hexagonal channels.