SYNTHESIS, CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF LN(2-X)SR(X)NIO(4+ -DELTA) SOLID-SOLUTIONS (LN=LA, ND, SM AND GD, SS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-1.67)/

New members of the Ln(2-x)Sr(x)NiO(4+/-delta) (Ln = La, Nd, Sm and Gd) solid solution series have been synthesized for x greater than or equ al to 1.0. The upper limit of x is ca. 1.6 for La and 1.67 for Nd, Sm and Cd. The tetragonal K2NiF4-type crystal structures of these phases have been Rietveld refined using X-ray powder diffraction data. Thermo gravimetry shows nickel to be in the +3 oxidation state. Magnetic susc eptibility data reveal Curie-Weiss behaviour for temperatures in the r ange 6-300 K. An approximate phase diagram for the Ln(2-x)Sr(x)NiO(4+/ -delta) system as a function of Ln(3+) radius and x is presented.