Cesium tetrachlorocuprate. Structure, crystal forces, and charge distribution

Abstract

The crystal and molecular parameters of cesium tetrachlorocuprate have been refined using an X-ray diffraction intensity data set. The crystal system is orthorhombic, space group Pnam, with four formula weights per unit cell; the unit cell parameters are a = 9.7599 ( 12), b = 12.3967 (12), and c = 7.6091 (9) A. A total of 1786 independent reflections were used in least-squares refinement of the molecular parameters, leading to a final R factor (on F) of 5.5%. The anion has crystallographically imposed m symmetry and the three independent copper-chlorine bond lengths are 2.244 (4), 2.235 (4), and 2.220 (3) A. The crystal forces acting upon the bonds within the anion were calculated, and after correction for their effects and for thermal motion the copper-chlorine bond length in an isolated anion is 2.283 A. The charge distribution within the anion is estimated to be [Cu°60-(3) (a) M.

Microscopic Modeling of Correlated Systems Under Pressure: Representative Examples

“…We find a systematic shift of the pressure scale which is needed to match the simulated and measured structures, similarly to other systems considered in this review . In the studied Cs 2 CuCl 4 system, this shift is approximately 1 GPa, since the optimized structure at 1 GPa reproduces the experimental structure at ambient pressure . One can argue then that the theoretical structures obtained at 1 GPa, 1.5 GPa, and 4.5 GPa provide good references for the measurements done at 0 GPa, 0.5 GPa, and 3.6 GPa, respectively.…”

“…[8,40,86,101,102] In the studied Cs 2 CuCl 4 system, this shift is approximately 1 GPa, since the optimized structure at 1 GPa reproduces the experimental structure at ambient pressure. [155] One can argue then that the theoretical structures obtained at 1 GPa, 1.5 GPa, and 4.5 GPa provide good references for the measurements done at 0 GPa, 0.5 GPa, and 3.6 GPa, [1] respectively.…”

Magneto‐Structural Properties of the Layered Quasi‐2D Triangular‐Lattice Antiferromagnets Cs2CuCl4−xBrx for x = 0, 1, 2, and 4

“…For the discussion of the magneto‐structural correlations in the compounds of Cs 2 CuCl 4− x Br x (0 ≤ x ≤ 2) it is useful to recall the results of structural investigations under pressure, so far available only for the x = 0 border compound. According to these X‐ray studies, performed up to 4.0 GPa, the structure stays orthorhombic, space group Pnma , up to 3.6 GPa with reduced lattice parameters compared to those at ambient pressure …”

“…According to these X-ray studies, performed up to 4.0 GPa, [11] the structure stays orthorhombic, space group Pnma, up to 3.6 GPa with reduced lattice parameters compared to those at ambient pressure. [22][23][24] . At low pressures up to about 0.6 GPa, which is relevant for the present study, the changes in the lattice parameters were found to be linear with pressure.…”

“…Lattice constant (a, b, c) d J (Å) d J 0 (Å) J/k B (K) J 0 /k B (K) J 0 / J Experimental structure [11,23] a microscopic analysis of the magnetic exchange coupling constants and their pressure dependences, we perform structure optimization simulations. The structural data of the experimental structure at ambient pressure (0 GPa) are rather well reproduced by the theoretically relaxed structure at 1 GPa.…”