V. Vohn, W. Kockelmann, U. Ruschewitz
Mar 4, 1999
Citations
1
Influential Citations
35
Citations
Journal
Journal of Alloys and Compounds
Abstract
Abstract By the reaction of BaCO 3 with graphite in an arc melting furnace single crystals of BaC 2 could be synthesized. Structural investigations confirm the tetragonal structure (space group: I 4/ mmm , Z = 2) given in the literature. In another approach polycrystalline BaC 2 of high purity could be prepared by the reaction of elemental barium and graphite at temperatures of about 1000 K. Temperature dependent X-ray powder investigations on this sample confirm the phase transition to a cubic phase (space group: F m 3 m , Z = 4) at about 520 K (1st order phase transition). At low temperatures a new monoclinic form of BaC 2 (space group: C 2/ c , Z = 4) was found which is isotypic to the crystal structure of ThC 2 at room temperature. This structure was refined from neutron TOF diffraction data at 20 K.