Hydrothermal and Structural Chemistry of the Zinc(II)- and Cadmium(II)-1,2,4-Triazolate Systems

Hydrothermal reactions of 1,2,4-triazole with zinc and cadmium salts have yielded 10 structurally unique materials
of the M(II)/trz/Xn- system, with M(II) = Zn and Cd and Xn- = F-, Cl-, Br-, I-, OH-, NO3-, and SO42- (trz =
1,2,4-triazolate). Of the zinc-containing phases, [Zn(trz)2] (1), [Zn2(trz)3(OH)]·3H2O (3·3H2O), and [Zn2(trz)(SO4)(OH)] (4) are three-dimensional, while [Zn(trz)Br] (2) is two-dimensional. All six cadmium phases, [Cd3(trz)3F2(H2O)]·2.75H2O (5·2.75H2O), [Cd2(trz)2Cl2(H2O)] (6), [Cd3(trz)3Br3] (7), [Cd2(trz)3I] (8), [Cd3(trz)5(NO3)(H2O)]·H2O
(9·H2O), and [Cd8(trz)4(OH)2(SO4)5(H2O)] (10), are three-dimensional. In all cases, the anionic components Xn-
participate in the framework connectivity as bridging ligands. The structural diversity of these materials is reflected
in the variety of coordination polyhedra displayed by the metal sites:  tetrahedral; trigonal bipyramidal; octahedral.
Structures 3, 5, and 7−9 exhibit two distinct polyhedral building blocks. The materials are also characterized by a
range of substructural components, including trinuclear and tetranuclear clusters, adamantoid cages, chains, layers,
and complex frameworks.