Tetrahedral Clusters of Copper(II): Crystal Structures and Magnetic Properties of Cu2Te2O5X2 (X = Cl, Br)
Citations Over TimeTop 10% of 2000 papers
Abstract
The isostructural compounds of general formula Cu2Te2O5X2 (X = Cl, Br) have been synthesized by chemical transport reaction. They crystallize in the tetragonal system, space group P4̄ with a = 7.6209(3) Å, c = 6.3200(4) Å, and a = 7.8355(2) Å, c = 6.3785(2) Å for Cu2Te2O5Cl2 and Cu2Te2O5Br2 respectively. The three-dimensional network is built up by tetrahedral clusters of copper(II) in distorted square planar coordination, isolated in the [100] and [010] directions by [Te2O5E2] groups and in the [001] direction by [TeO3E] tetrahedra. This leads to what can be described as spin tubes in the [001] direction surrounded by large tunnels where 5s2 tellurium(IV) lone pairs and chlorine and bromine atoms interact. A careful analysis of the temperature dependence of the susceptibility reveals that even from the magnetic point of view, the building bricks are tetrahedra with all couplings roughly equivalent, and not squares with small diagonal couplings. These systems are thus expected to have very interesting magnetic properties, including a large singlet−triplet gap, and a band of singlet states inside this gap.
Related Papers
- → Synthesis and crystal structure of two new oxychalcogenides: Eu5V3S6O7 and La10Se14O(2002)9 cited
- → Synthesis and crystal structure of the heteropolyvanadate anion [AsV12P40(VO)2]9−(1993)27 cited
- → The novel R2Ba1.25NiO5.25 (R = Tm, Yb, Lu) structure type(1991)15 cited
- → Crystal structure of α-Li2.5Al0.5SiO4(1991)9 cited
- → MoAlP2O9molybdenum(V) aluminophosphate isostructural with VSiP2O9(1990)6 cited