Mat. Res. Bull. Vol. 4, pp. 377-380, 1969. Pergamon Press, Inc. Printed in the United States. AgSbO3: CHEMICAL CHARACTERIZATION AND STRUCTURAL CONSIDERATIONS E. A. W. Sleight Central Research Department* I. du Pont de Nemours and Company Wilmington, Delaware 19898 (Received April 21, 1969; Communicated by J. B. Goodenough) ABSTRACT It is confirmed that AgSbO 3 has a pyrochlore related structure without being hydrated. Furthermore, attempts to prepare Ag2Sb205(OH)2 or Ag2Sb205F 2 were unsuccessful. It is concluded that the occurrence of the pyrochlore structure instead of the perovskite structure for certain ABO 3 compounds is the result of very strong covalent bonding which tends to restrict oxygen to a maximum coordination number of four. Introduction Compounds of the type ASbO 3 have been reported (1) to have the pyro- chlore structure where A is Ag, Na, or K. However, the usual formula for the pyrochlore structure is A2B207, not ABO3, and several workers (2, 3) have recently shown that NaSbO 3 really has the ilmenite structure. Only the hydrated form of NaSbO 3 possesses the pyrochlore structure, and its formula can be written as Na2Sb206 • H20 or Na2Sb205(OH)2. The purpose of this in- vestigation was to determine whether AgSbO 3 must also be hydrated to have the pyrochlore structure. Experimental Four different preparative methods were used. *Contribution No. 1560. 377