On the solid solution Sr (1.45–x) Ca x Sb 0.55 O 3–y M. Saidi a,b,c , E. Moran c , U. Amador d, *, M. Abboudi b , A. Asskali a a Dpt. de Ge ´nie Chimique, Faculte ´ des Sciences et Techniques de Tanger, Universite ´ Abdelmalek Essaadi, B.P. 416 Tanger, Morocco b Dpt. de Chimie, Faculte ´ des Sciences de Te ´touan, Universite ´ Abdelmalek Essaadi, B.P. 2121 Te ´touan, Morocco c Dpto. de Quı ´mica Inorga ´nica, Facultad de Ciencias Quı ´micas, Universidad Complutense de Madrid, Ciudad Universitaria, E-28040 Madrid, Spain d Dpto. de Quı ´mica Inorga ´nica y Materiales, Facultad de Ciencias Experimentales y Te ´cnicas, Universidad San Pablo CEU, Urb. Monteprı ´ncipe, 28668 Boadilla del Monte, Madrid, Spain (Refereed) Received 10 August 1999; accepted 1 October 1999 Abstract Several compositions in the system Sr (1.45–x) Ca x Sb 0.55 O 3–y (0 x 1.45) have been synthesized by solid state reaction in air at 1000°C and investigated by powder X-ray diffraction and EDS microanalysis. They exhibit good thermal stability up to 1200°C. The solid solution range was delimited in the composition 0 x 1.1. For quantities of Ca 2+ higher than 1.1, the amount of solid solution decreases and another phase, Ca 6 Sb 2 O 10 , appears. The lattice parameters of the system Sr (1.45–x) Ca x Sb 0.55 O 3–y decrease with increasing Ca 2+ content. © 2000 Elsevier Science Ltd. All rights reserved. Keywords: A. Inorganic compounds; B. Chemical synthesis; C. X-ray diffraction; D. Phase equilibria 1. Introduction Soon after the discovery of the high-T c Bi-cuprate family of superconductors with general formula Bi 2 Sr 2 Ca n–1 Cu n O y (n = 1, 2, 3) [1–5], several attempts to partially or completely substitute Sb for Bi, with the aim of improving the properties of these materials, were * Corresponding author. Fax: 34-91-3510475. E-mail address: UAMADOR@CEU.ES (U. Amador). Pergamon Materials Research Bulletin 35 (2000) 1269 –1275 0025-5408/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved. PII: S0025-5408(00)00318-4