Cu 5SbO 6 is found to have a monoclinic, Delafossite-derived structure consisting of alternating layers of O-Cu(I)-O sticks and magnetic layers of Jahn-Teller distorted Cu(II)O 6 octahedra in an edge sharing honeycomb arrangement with Sb(V)O 6 octahedra. This yields the structural formula Cu(I) 3Cu(II) 2Sb(V)O 6. Variants with ordered and disordered layer stacking are observed, depending on the synthesis conditions. The spin 1/ 2 Cu 2+ ions form dimers in the honeycomb layer. The magnetic susceptibility measured between 5 and 300 K is characteristic of the presence of a singlet-triplet spin gap of 189 K. High resolution synchrotron X-ray diffraction studies indicate that changes in the intra- or interdimer distances between 300 and 20 K, such as might indicate an increase in strength of the Peierls-like distortion through the spin gap temperature, if present, are very small. A comparison to the NaFeO 2-type Cu 2+ honeycomb compounds Na 3Cu 2SbO 6 and Na 2Cu 2TeO 6 is presented.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry