Thorium Transition Metals Ternary Germanides

New ternary germanides of the general compo sition ThM2Ge2 were found to exist in the systems Th-Cr-Ge, Th-Mn-Ge, Th-Fe -Ge, Th-Co- Ge, Th-Ni- Ge and Th- Cu-Ge. The crystal structure analysis by means of the x - ray powder diffraction method showed that these compounds are isostructural with the compounds ThM2Si2 (M = Cr, Mn, Fe, Co, Ni and Cu), discdvered in this labo.ratory,, The tetragonal unit cell contains two formula units. Space group is !4/mmm. The atomic positions of thorium and the transition metal are defined by special position 2(a) and 4(d), respectively, while the variabl e 2arameter z determining the position 4(e) of the germanium atoms was obtained by computing the ele ctroi;i. density distribution along the c-axis

The Floating-Zone Refining of Silicon by Electron Beam Heating

The contamination o.f a melt c aused by the material of the container is completely avoided by the float ing zoine method. For this reason the\u27 method, firstly realized by P. H. Keck and M. J. Golay1, is nowadays u sed very oft~n for obtaining various materials of extremely high purity. The method is especially valuable in the case of chemically active melts and certainly it is the best way for obtaining single c rystals when extreme purity is primarily required. Zone melting can be achieved by different heating techniques, high frequency being used mostly. Electron beam heating wais introduced by A. Calverley et al.2 Ln the case o f ma•terials with very high melting point it has the advantage over high frequency heating. In the present article an improvement of this method as well as details of the equipment and floating zone refining of silicon are described

The Preparation and Crystal Structure of Some Ternary Silicides Containing Uranium and Transition Metals

The crystal structure of some new ternary silicides of the general composition U 4M 5Si3 (M = Cr, Mn, Fe) h as been determined by means of the x-ray powder diffraction method. The structure which belongs to the C14 (MgZn2) type is characterized by a statistical distributio\u27n of both kinds of smaller atoms. The chemical composition of the monophase specimens is probably temperature dependent. At lower temperatures it may aproach the formula U2M 3Si. In some of these systems ternary compounds UM2Si2 were also identified. They were found to be isostructural with the previously reported ThM2Si2 compounds. A novel method for the preparation of uranium alloys with the use of the electron beam melting is described