Ba2Ni3: A missed intermetallic compound

Abstract

The reinvestigation of the binary system Ba-Ni revealed the existence of Ba2Ni3 in the temperature range 450 °C-800 °C. Single crystals were grown at 700 °C in the presence of excess barium, followed by separation from the melt by use of the high-temperature centrifugation aided filtration technique, HTCAF. At ambient temperature Ba 2Ni3 is in a metastable state which slowly transforms to the elements (side-phases of the binary system). The extreme softness and the mechanical instability of the hygroscopic Ba2Ni3 particles prevented a single crystal structure determination. The crystal structure was solved from X-ray powder diffraction data (P$\bar{3}$m1 (No. 164), a = 419.97(2) pm, c = 913.32(3) pm) and revealed Ba2Ni3 to be an isotype of Sr2Ni3 which was reported only recently. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.