Cr(V)-Cr(V) dimers in Ae4[Cr2N6] (Ae = Ca and Sr)

Single crystals of the isostructural compounds Ae4[Cr2N6](Ae = Ca and Sr) were synthesised from the elements in a mixed sodiumgallium melt at 900 °C. The reactions were performed in sealed niobium tubes with NaN3 as the nitrogen source. The compounds crystallise in the triclinic space group P1(No. 2) with similar lattice parameters. The structure contains [Cr2N6]8-, isolated anionic units of edge-sharing tetrahedra that permit chromium-chromium bonding.