The crystal structure of Tm5Re2O12.

The crystal structure of Tm(5)Re(2)O(12), pentathulium dirhenium dodecaoxide, was determined by synchrotron diffraction on a reticular merohedral twin, revealing space group C2/m with a = 12.3717 (7), b = 5.6744 (3), c = 7.4805 (4) Å, beta = 107.816 (2) degrees and Z = 2. Distorted ReO(6) octahedra form chains with alternating rhenium-rhenium distances of 2.455 (1) and 3.219 (1) Å. Early reports on Ln(2)ReO(5) compounds are critically reviewed in the light of our results for Tm(5)Re(2)O(12).