Preparation, Crystal Structure, and Magnetic Studies of a New Sr7Re4O19 Double Oxide and Its Relation to the Structure of Ba7Ir6O19

The complex oxide Sr 7 Re 4 O 19 has been synthesized and its crystal structure was determined by X-ray diffraction powder data analysis (space group C 2/ m ; a =13.6379(3) A, b =5.6035(2) A, c =10.3700(3) A; β =98.348(2)°, Z =2, R I =0.018, R P =0.050). The compound crystallizes in a new structure type, which can be derived from the Ba 7 Ir 6 O 19 structure by removing the Ir atoms from the middle octahedron of three face-sharing IrO 6 octahedra units. This change results in the infinite cis -bridged chains of the ReO 6 octahedra linked together by common corners. Each chain is connected with another one by the corner-sharing of each second ReO 6 octahedron. The 10- and 12-coordinated Sr atoms are situated between these infinite structure fragments. Magnetic properties of the Sr 7 Re 4 O 19 compound were studied by SQUID measurements.