ИСТИНА

There were discovered in Ce-Ru-Ga and La-Ru-Ga systems several new compounds with homogeneity ranges CeRu3-xGax, LaRu3-xGax and Ce2Ru7-xGax. Small single crystals acceptable for X-ray single-crystal analysis were obtained from synthesized samples. As a result the structures and the compositions of new intermetallics were determined - CeRu1.7Ga1.3, LaRu2.33Ga0.67 and Ce2Ru4Ga3. First two intermetallics crystallize in trigonal unit cell with space group R-3m, Z = 9, while Ce2Ru4Ga3 compound crystallizes in hexagonal unit cell of P63mc space group, Z = 4. The parameters of the CeRu1.7Ga1.3 unit cell are: a = 5.4149(13), c = 25.148(6) Å; LaRu2.33Ga0.67: a = 5.4442(4), с = 25.744(2) Å; Ce2Ru4Ga3: a = 5.4394(3), c = 24.641(2) Å. The structures of CeRu1.7Ga1.3 and LaRu2.33Ga0.67 intermetallics belong to PuNi3 type and are structural analogues of YbZn1.9Al1.1 [1], DyFe2.6Al0.4 [2], UCo1.8Al1.2 [3] и YbCuAl2 [4] compounds. The similar structure of Ce2Ru4Ga3 intermetallic belongs to Gd2Co7 type [5]. The three new structures contain similar nets consisting of one or several sorts of atoms depending on the composition. One more new compound with composition Ce2Ru6Ga7 also exhibits those recognizable atom layers which are analogous to ones in CeRu3-xGax, LaRu3-xGax and Ce2Ru7-xGax compounds. The homogeneity ranges of new intermetallics were defined based on EMPA data: CeRu3-xGax compound exists in 1.3≤x≤1.7 region, LaRu3-xGax compound – in more extended region – 0.67≤x≤2.33, and Ce2Ru7-xGax - 3≤x≤3.5. Leave one line blank [1] Mazzone D., Manfrinetti P., Fornasini M., J. Solid State Chem. 182 (2009) 2344-2349. [2] Stel`makhovich B., Kuz`ma Yu., Babizhet`sky V., J. Alloys Compd. 190(2) (1993) 161-164. [3] Lupsa I., Lucaci P., Burzo E., J. Alloys Compd. 204(1-2) (1994) 247-250. [4] Chen Y.-Q., Liang J.-K., Li J.-B., Rao G.-H., Powder Diffraction. 25(4) (2010) 349-354. [5] Virkar A.V., Roman A., J. Les. Com. met. 18 (1969) 59