A.I. Tursina

CeRu2Al10 with the YbFe2Al10 structure type

The structure of cerium diruthenium decaaluminium, CeRu2Al10, is characterized by seven crystallographic sites in space group Cmcm, viz. Ce in 4c, Ru in 8a, two Al atoms in 8g, two Al atoms in 8f and one Al atom in 8e. The structure can be interpreted as a stacking of alternating columns running along [001], each formed by only one type of Ru cuboid with composition RuAl6 or CeRuAl4.

Crystal structure of the new compound Ce3Pt23Si11

Abstract The crystal structure of the new ternary compound, Ce 3 Pt 23 Si 11 , was determined by X-ray analysis of a single crystal (Enraf-Nonius CAD-4 diffractometer, Mo Kα radiation, 585 independent reflections, R =0.0487). The Ce atoms have only one crystallographic position with a very rare tetragonal prism coordination polyhedron.

Crystal and molecular structures of complexes of diethyldibromotin with triphenylphosphine oxide and hexamethylphosphoric triamide

The crystal and molecular structures of the Et/sub 2/SnBr/sub 2/ x 2TPPO complex and two crystal modifications of the Et/sub 2/SnBr/sub 2/ x 2HMPT complex were determined by x-ray diffraction analysis. The complexes are mononuclear, and the coordination polyhedron of the tin atom is a slightly distorted octahedron. The regularities of cis weakening of the Sn-Br and Sn-O bonds under the influence of donor ethyl groups were ascertained.

Phase relationships in the Ce-Pd-In system

The interaction of cerium with palladium and indium was studied, and the 773°C isothermal section of the Ce-Pd-In phase diagram was plotted using physicochemical methods: X-ray powder diffraction, single-crystal X-ray diffraction, and electron probe microanalysis. The existence of 12 ternary intermetallic phases in the title system was confirmed, and three new phases were discovered. Crystal structure was determined for seven intermetallic compounds. A single-crystal X-ray diffraction study of CePdIn was carried out for the first time. A high-temperature phase CePdIn4 was found, and its crystal structure was solved.

Ce2Ru3Al15, an intermetallic compound of a new structure type

The title compound, dicerium triruthenium pentadecaaluminium, is a new intermetallic compound from the Al-rich region of the Ce–Ru–Al phase diagram. Two Ce atoms (6g and 2a sites of space group P63/mcm) are coordinated by 18 atoms, one Ru atom (12i site) and five Al atoms (12k, 12i, 12j, 12j and 12k sites) have 12 nearest neighbours each.

New orthorhombic modification of equiatomic CePdAl

The crystal structure of a new low-temperature modification of CePdAl was determined from single-crystal x-ray data: CePdAl-type; space group Pmmn (No. 59), Z = 14, oP42, a = 0.426 07 nm, b = 2.887 58 nm, c = 0.721 90 nm; RF = 0.048. Physical properties of orthorhombic CePdAl are governed by a mutual balance of the RKKY interaction, the Kondo effect and crystalline electric field splitting, resulting in antiferromagnetic ordering below ≈2.5 K. Electronic transport is reminiscent of a textbook-like Kondo lattice, which comes along with a significant negative magnetoresistance of more than 50% at low temperatures. Although geometrical frustration is absent when compared to the hexagonal modification of CePdAl, the ordering temperature TN is even smaller. A possible cause is enhanced Kondo interactions.

Synthesis and crystal structure of a new ternary intermetallic compound Ce16Ru8+x In3-x (0 < x < 1.0)

A study of phase equilibria in the Ce-Ru-In ternary system showed the presence of a new ternary compound Ce16Ru8+xIn3−x, which exists in the range of 0 < x < 1.0. According to a single-crystal X-ray diffraction study of Ce16Ru8+xIn3−x (x = 0.29), this compound crystallizes in the tetragonal system and represents a new structural type: a = 11.8047(15) Å, c = 9.5464(13) Å, space group. P4/mbm, Z = 2, RF = 0.059, Rw = 0.124. A specific feature of this structure is the presence of short Ce-Ru distances (2.575(3)Å).

Structural analysis of modulated crystals. A new structure of Ce4Pd13.6Sn5.9

Incommensurate modulated structure of Ce4Pd13,6Sn5,9 intermetallic is studied by (3+1)D analysis in a rhombic basic cell a = 2.08458(4) nm, b = 0.47129(1) nm, and c = 0.92874(1) nm; q = 0,2407(1)b*. Xmmm(0β0)000 group determines the symmetry of the crystal. The superspace analysis is compared to the analysis of the superstructure with a, 4b, and c periods in three dimensions.

Ring contraction of 1,2,4,5,7,8-hexaoxa-3-silonanes by selective reduction of COOSi fragments. Synthesis of new silicon-containing rings, 1,3,5,6-tetraoxa-2-silepanes.

The reducing agents Ph(3)P, (C(8)H(17))(3)P, or NH(2)C(S)NH(2) promote the ring contraction of nine-membered triperoxides, viz., 1,2,4,5,7,8-hexaoxa-3-silonanes, giving rise to seven-membered rings belonging to the previously unknown class of monoperoxides, viz., 1,3,5,6-tetraoxa-2-silepanes, in yields from 67% to 91%. Therefore, the selective reduction of the SiOOC fragments to SiOC in molecules containing simultaneously the COOC fragment was performed for the first time.

A new ternary indide, Ce20Pd36In67

The intermetallic compound, cerium palladium indide, Ce20Pd36In67, crystallizes in a new structure type in which atoms have significantly distorted polyhedra with coordination numbers CN 15–18 for Ce and CN 8–13 for Pd and In.