STRUCTURES OF [AG(TCM)], [AG(TCM)(PHZ)(1 2)] AND [AG(TCM)(PYZ)] (TCM = TRICYANOMETHANIDE, C(CN)(3)(-), PHZ = PHENAZINE, PYZ = PYRAZINE)/

The topologically unique sheet structure of [Ag(tcm)] [tcm = the tricy anomethanide ion, C(CN)(3)(-)] is retained in the derivative [Ag(tcm)( phz)(1/2)] (phz = phenazine). The sheet structure is composite, consis ting of two independent hexagonal grid nets which are corrugated so as to allow one to interpenetrate the other. The Ag+ ion is three-coordi nate and provides half the three-connecting nodes of the hexagonal gri d net, the others being provided by the tcm central carbon. [Ag(tcm)(p hz)(1/2)] contains essentially the same composite double sheets linked together by phenazine units that bridge between silver centres which thereby become four-coordinate. The topology of [Ag(tcm)(pyz)] (pyz = pyrazine) is very different; in this case the Ag(tcm) component forms a planar, non-corrugated hexagonal grid and each such sheet is connect ed on both sides to neighbouring sheets by pyrazine bridging ligands w hereby the silver becomes five-coordinate and trigonal bipyramidal. Tw o such 3,5-connected three-dimensional nets then interpenetrate.