Eleven new ternary compounds RTi6Sn4 (R = La-Nd, Sm) and RTi6Pb4 (R = Y, Gd-Er) were synthesized by arc-melting under purified argon. The crystal structures were refined from Xray powder diffraction data (structure type ZrFe6Ge4, Pearson symbol hR33, space group R-3m (#166)). They can be described as a stacking of layers formed by the coordination polyhedra of the Sn (Pb) atoms along the crystallographic direction [001].

The phase equilibria in the Ce-Ti-Sb and Gd-Ti-Sb ternary systems at 600°C were established by means of X-ray powder diffraction and EDX analysis. The formation of two ternary compounds in the Ce-Ti-Sb system, Ce 3 TiSb 5 (Hf 5 CuSn 3 type) and Ce 2 Ti 7 Sb 12 (La 2 Ti 7 Sb 12 type), and of one ternary compound in the Gd-Ti-Sb system, Gd 2 Ti 11 Sb 14 (Sm 2 Ti 11 Sb 14 type), was confirmed. At 600°C, seven binary compounds were found to exist in the Ti-Sb system, four in the Ce-Sb system, and four in the Gd-Sb system. No binary compounds form in the {Ce, Gd}-Ti systems. The crystal structures of the Ce 2 Ti 7 Sb 12 and Gd 2 Ti 11 Sb 14 compounds were refined on X-ray powder diffraction data, starting from the initial atomic parameters of the La 2 Ti 7 Sb 12 and Sm 2 Ti 11 Sb 14 structure types, respectively. The isothermal sections of the phase diagrams of the Ce-Ti-Sb and Gd-Ti-Sb ternary systems at 600°C were constructed in the whole concentration range.

The isothermal section of the phase diagram of the ternary system Ce-Ti-Sn was constructed in the whole concentration range at 600°C by means of X-ray powder diffraction. The binary compounds of the systems Ce-Sn and Ti-Sn dissolve negligible amounts of the third component. Two ternary compounds, CeTi 6 Sn 4 and ~Ce 3 TiSn 5 , were found. The crystal structure of the compound CeTi 6 Sn 4 belongs to the structure type ZrFe 6 Ge 4 (Pearson symbol hR33, space group R-3m, a = 5.8101(11), c = 22.971(5) Å). It completes the row of isotypic RTi 6 Sn 4 compounds with ZrFe 6 Ge 4-type structure (R = Y, LaNd , Sm, Gd-Tm, Lu).

No abstract

The phase equilibria in the ternary systems {Ce, Gd}–{Ti, Zr}–Sb were investigated by means of X-ray powder diffraction and energy-dispersive X-ray spectroscopy. The isothermal sections of the phase diagrams at 600°C were constructed. The formation of three ternary compounds (Ce2Ti7Sb12, Ce3TiSb5, and Gd2Ti11Sb14) was confirmed in the {Ce, Gd}–Ti–Sb systems and no more ternaries were found. The investigation of the {Ce, Gd}–Zr–Sb systems revealed several new ternary compounds and confirmed the known ones. The crystal structure of the new compound Ce0.08(3)Zr1.92(3)Sb was determined from X-ray powder diffraction data. The other new compounds in the Ce–Zr–Sb system were found to have compositions close to ~CeZrSb4 and ~Ce2Zr3Sb5. In the Gd–Zr–Sb system the existence of a large homogeneity range was established for the GdZrSb compound along the isoconcentrate 33.3 at.% Sb: Gd1-xZr1+xSb (x = 00.905(18) at 600°C), and a new compound, ~Gd3Zr3Sb14, was discovered. The crystal structures at the boundary compositions of the Gd1-xZr1+xSb phase were refined from X-ray powder diffraction data.