A layered oxycarbonate involving trivalent chromium: Sr4FeCrO6CO3

The possibility to synthesize layered oxycarbonates involving trivalent chr omium has been shown for the first time for the compound Sr4Fe2-xCrxO6CO3, with 0 less than or equal to x less than or equal to 1. The structural stud y of Sr4FeCrO6CO3 using NPD, HREM, Mossbauer, and XANES, shows that this ph ase, which is closely related to n = three-member of the Ruddlesden-Popper family, is built up of layers of corner-sharing CrO6 octahedra and FeO5 pyr amids. Between the layers the triangular CO3 groups, parallel to be or ac p lanes, are connected to the CrO6 octahedra, adopting a "coat-hanger" config uration. The antiferromagnetic behavior of this phase (T-N = 125 K) is fund amentally different from the magnetic behavior of Sr4Fe2O6CO3.