I Mat. Res. Bull., Vol. 28, pp. 39-44, 1993. Printed in the USA. 0025-5408/93 $6.00 + .00 Copyright (c) 1993 Pergamon Press Ltd. STRUCTURE REFINEMENT OF A NEW SULFIDE OF COPPER AND IRON WITH LAYERED STRUCTURE J.Llanos, C. Contreras-Ortega and C. Mujica Departamento de Quimica, Facultad de Ciencias, Universidad Cat61ica del Norte, Casilla 1280, Antofagasta, Chile H.G. von Schnering and K. Peters Max Planck Institut for Festk6rperforschung, Heisenbergstr. 1, W-7000 Stuttgart 80, Federal Republic of Germany (Received November 30, 1992; Communicated by P. Hagenmuller) ABSTRACT. NaCuFeS2, trigonal, P3ml, (N ° 164), a=386,3(1), c=687.3(1) pm., Z=I, cristallizes in a layer type Li2FeS2 - structure. In the hcp sublattice tetrahedral sites are statistically ocuppied by copper and iron forming CuFeS2 .The sodium ions are distributed in the octahedral sites between the sheets. MATERIAL INDEX : Copper, Iron , Layerstructure, Disulfides Introduction Since the first publications on lamellar chalcogenides [1-4] , the search for news compounds able to be used as cathode in secondary batteries, has led in apropiate investigations. As it has been shown that ternary sulfides of transition elements have a higher electrical conductivity than the binary sulfides, intensive research has been developed in this direction and novel compounds such as lJxCuFeS2, LixCuMo6S8, etc reported [5-9] . In order to study the electrochemical properties of such materials and to gain better understanding of the intercalation mechanisms, it seemed 39