Experimental nearest-neighbor Cl–Cl distance in Rb2IrCl6

Determine the experimental nearest-neighbor Cl–Cl superexchange distance in Rb2IrCl6 to establish its relationship with the antiferromagnetic transition temperature across the alkali iridium hexachloride series.

Background

The paper compares antiferromagnetic transition temperatures with nearest-neighbor Cl–Cl distances because the Cl–Cl separation controls the Ir–Cl–Cl–Ir superexchange pathway. For Rb2IrCl6, however, the authors report that no experimental distance is available and that only a calculated value has been reported. Consequently, the experimental structural parameter remains unresolved in the comparison.

References

It should be noted here that the Cl-Cl experimental distance is not known for the Rb$_2$IrCl$_6$ while only a calculated value along with transition temperature has been reported, and in Fig.~5 only these numbers have been summarized.

— Na$_2$Ir$^\text{IV}$Cl$_6$: The Missing Member of the Perfectly Cubic Vacancy Ordered $A_2$IrCl$_6$ Family, Another Potential $J_{eff}$ = $\frac{1}{2}$ Ground State Candidate  (2610.01371 - Soren et al., 1 Oct 2026) in Section 3.4, Magnetic Properties