[en] Ternary intermetallic compound Sm${}_2$Ru${}_3$Sn${}_5$ was synthesized in the system Sm-Ru-Sn by arc-melting and annealing at 600 °C in the field with high content of Sn. Its crystal structure was determined using single crystal X-ray diffraction data (at 240 K). The compound crystallizes in cubic system with space group I$\stackrel{¯<!--\; ??\; -->}{4}$3m (No. 217), unit cell parameter is a = 9.4606 (8) Å, Z = 4, Pearson symbol c/40. The intermetallic compound Sm${}_2$Ru${}_3$Sn${}_5$ represents an ordered version of the centrosymmetric Ru${}_3$Sn${}_7$ structure (space group Im$\stackrel{¯<!--\; ??\; -->}{3}$m), in which 16f Sn-filled crystallographic site is split into two 8c sites, each of which is solely occupied of one sort of atoms – Sn or Sm. The occupation of these two 8c sites leads to a reduction of symmetry due to the removal of the inversion center.

[en] Graphical abstract: -- Highlights: • The new polymorphic modification of CeRuSn was studied by X-ray diffraction methods. • CeRuSn(II) is a superstructure of CeCoAl-type with tripling of the subcell along c axis. • In CeRuSn(II) two crystallographic Ce sites has strongly shortened Ce–Ru contacts. -- Abstract: The atomic order of the new polymorphic modification of the equiatomic stannide CeRuSn was established from single crystal X-ray diffraction data. The new modification of CeRuSn can be described as a superstructure of CeCoAl-type with tripling of the subcell along the c axis. Space group C2/m, lattice parameters a = 11.5702(12) Å, b = 4.7529(5) Å, c = 15.2414(16) Å, β = 103.511(2)°, Z = 12. The structure was refined to R1 = 0.034 for 1806 F² and 55 variables. The new modification has three independent crystallographic Ce sites, two of which form strongly shortened Ce–Ru contacts d_Ce1–Ru2 = 2.267 Å, d_Ce3–Ru1 = 2.434 Å and d_Ce3–Ru3 = 2.429 Å

[en] Highlights: ► Single crystal X-ray experiment showed that Dy₂PdGe₆ is isotypic with Ce₂GaGe₆-type. ► Powder diffraction test has confirmed the single crystal result. ► Powder diffraction of La₂PdGe₆ and Dy₂PtGe₆ suggests the similar structures. - Abstract: The crystal structure of Dy₂PdGe₆ was studied by X-ray diffraction on single crystal. Space group Cmca (No. 64), a = 8.1337(16), b = 8.0208(16), c = 21.441(4) Å, V = 1398.8 ų, Z = 8, 1259 unique reflections with I > 2σ(I₀) in refinement (2Θ_max = 75.81°), down to R1 = 0.029, wR2 = 0.071. The title compound represents an ordered derivative from the Ce₂GaGe₆-type. The crystal structure can be presented as a sequence of the AlB₂-type slabs, quadrangular antiprisms slabs, and distorted αPo-type slabs along the c direction. The atomic order in Dy₂PdGe₆ derived from the single crystal data was confirmed by X-ray powder diffraction with cell parameters a = 8.1348(6), b = 8.0145(5), c = 21.4396(14) Å.

[en] Highlights: • RE₅Ru₃Ga₂ (RE = La, Ce, Pr, and Nd) crystallize with a cubic structure of the La₅Ru₃Al₂ type. • Upon small substitution of Al for Ga, a LT trigonal variant of Ce₅Ru₃Ga₂ can be stabilized. • LT-Ce₅Ru₃Ga_2−xAl_x of Ce₅Ru₃Al₂ structure type is characterized by very short Ce-Ru distances. • The cubic Ce₅Ru₃Ga₂ orders magnetically at T_C = 1.7 K. • Electrical conductivity of this material bears a Kondo lattice character. -- Abstract: Novel ternary gallides RE₅Ru₃Ga₂ (RE = La, Ce, Pr, and Nd) crystallize with a cubic structure of the La₅Ru₃Al₂ type (space group I2₁3) with the lattice parameters: a = 9.9082(3), 9.6926(4), 9.7509(5), and 9.7222(4) Å, respectively. Upon small substitution of Al for Ga (≤1 at% Al), the compound Ce₅Ru₃Ga_2−xAl_x can be stabilized as a low-temperature trigonal variant (space group R3). The latter phase, bearing the unit cell parameters a = 13.7892(3) Å and c = 8.3095(2) Å, is closely related to the Ce₅Ru₃Al₂ structure type. Its characteristic structural feature is the presence of very short interatomic Ce-Ru distances of 2.40(4) Å. The cubic Ce₅Ru₃Ga₂ exhibits Curie-Weiss paramagnetism with notably reduced effective magnetic moment. At T_C = 1.7 K, the compound orders magnetically, probably with a ferrimagnetic magnetic structure. The metallic-like electrical conductivity of this material bears a Kondo lattice character.

[en] Highlights: •Novel intermetallic phases Ce₄Ru₃Ga₃ and La₃Ru₂Ga₂ with new structural types. •Unusual short Ce–Ru contact of 2.7167 Å in Ce₄Ru₃Ga₃. •The average valence of cerium in intermetallic Ce₄Ru₃Ga₃ is higher than three. •The Ce₄Ru₃Ga₃ compound exhibits metallic conductivity. •Cerium atom adopts an intermediate valence state. -- Abstract: Novel intermetallic phases Ce₄Ru₃Ga₃ and La₃Ru₂Ga₂ were synthesized by arc melting the elemental components. The Ce₄Ru₃Ga₃ compound crystallizes with the orthorhombic unit cell of new structural type (space group Pnna, Z = 4) and the lattice parameters: a = 7.719(4) Å, b = 18.578(12) Å, c = 5.673(3) Å; while the La₃Ru₂Ga₂ compound has the monoclinic unit cell of new type (space group P2₁/m, Z = 6) and the lattice parameters: a = 5.8170(15) Å, b = 13.980(3) Å, c = 12.224(3) Å, β = 97.958(6)°. The characteristic feature of the Ce₄Ru₃Ga₃ structure is very short distance of 2.7167 Å between one of the ruthenium atoms and one of the cerium atoms. This cerium atom adopts the intermediate valence state, which is reflected in the characteristic temperature dependence of the magnetic susceptibility of Ce₄Ru₃Ga₃ and was directly confirmed by XANES spectroscopy. The latter experiment yielded the average valence of cerium ions near room temperature to be 3.19 ± 0.01. The compound exhibits metallic conductivity, fully consistent with its intermediate valence character

[en] Phase relations in the ternary system Ce-Pd-Si have been established for the isothermal section at 800 deg. C based on X-ray powder diffraction and EMPA techniques on about 130 alloys, which were prepared by arc-melting under argon or powder reaction sintering. Eighteen ternary compounds have been observed to participate in the phase equilibria at 800 deg. C. Atom order was determined by direct methods from X-ray single-crystal counter data for the crystal structures of τ₈-Ce₃Pd₄Si₄ (U₃Ni₄Si₄-type, Immm; a=0.41618(1), b=0.42640(1), c=2.45744(7) nm), τ₁₆-Ce₂Pd₁₄Si (own structure type, P4/nmm; a=0.88832(2), c=0.69600(2) nm) and also for τ₁₈-CePd_1-xSi_x (x=0.07; FeB-type, Pnma; a=0.74422(5), b=0.45548(3), c=0.58569(4) nm). Rietveld refinements established the atom arrangement in the structures of τ₅-Ce₃PdSi₃ (Ba₃Al₂Ge₂-type, Immm; a=0.41207(1), b=0.43026(1), c=1.84069(4) nm) and τ₁₃-Ce_3-xPd_20+xSi₆ (0≤x≤1, Co₂₀Al₃B₆-type, Fm3-barm; a=1.21527(2) nm). The ternary compound Ce₂Pd₃Si₃ (structure-type Ce₂Rh_1.35Ge_4.65, Pmmn; a=0.42040(1), b=0.42247(1), c=1.72444(3) nm) was detected as a high-temperature compound, however, does not participate in the equilibria at 800 deg. C. Phase equilibria in Ce-Pd-Si are characterized by the absence of cerium solubility in palladium silicides. Mutual solubility among cerium silicides and cerium-palladium compounds are significant whereby random substitution of the almost equally sized atom species palladium and silicon is reflected in extended homogeneous regions at constant Ce-content such as for τ₂-Ce(Pd_xSi_1-x)₂ (AlB₂-derivative type), τ₆-Ce(Pd_xSi_1-x)₂ (ThSi₂-type) and τ₇-CePd_2-xSi_2+x. The crystal structures of compounds τ₄-Ce_∼8Pd_∼46Si_∼46, τ₁₂-Ce_∼29Pd_∼49Si_∼22, τ₁₅-Ce_∼22Pd_∼67Si_∼11, τ₁₇-Ce_∼5Pd_∼77Si_∼18 and τ₁₈-CePd_1-xSi_x (x∼0.1) are still unknown. - Abstract: Phase relations in the ternary system Ce-Pd-Si have been established for the isothermal section at 800 deg. C based on X-ray powder diffraction, metallography, SEM and EMPA techniques on about 130 alloys. 18 ternary compounds were observed. Display Omitted