SR6ND3CU6O17 - AN INTERGROWTH OF THE 123-PHASE AND ROCK SALT-TYPE STRUCTURE

A new layered cuprate, Sr6Nd3Cu6O17, has been synthesized using an argon flow. The structure of this orthorhombic phase (a = 3.7547 Å, b = 11.4882 Å, c = 20.0976 Å) determined by neutron diffraction, is closely related to the "0212"-type and to the "123" structures. It can be described as an intergrowth of YBa2Cu3O7-type layers with rock salt-type (RS) layers according to the formulation [Sr 7 6Nd 5 6Cu2O4.66]"123"[Sr 5 6Nd 1 6O]RS. The CuO5 pyramids and especially the CuO4 groups are strongly distorted. The distribution of the strontium and neodymium cations, which seems to be an important factor for the stabilization of this framework, is discussed. © 1991.