Search

Novel ternary intermetallic phase Ce2RuGe was synthesized via arc-melting of the constituents and subsequent annealing at 700°С. Its crystal structure was determined from the powder X-ray diffraction data collected at room temperature. The compound crystallizes in the orthorhombic structure of a new type: space group Pmmn (No. 59), lattice parameters: a = 4.38235(5) A, b = 4.31818(5) A, c = 9.91496(15) A, Z = 2, Pearson symbol oP8. In the fully ordered unit cell of Ce2RuGe, there are two crystallographic positions for Ce atoms, single site with Ru atoms, and single site with Ge atoms, each with the multiplicity of two. The crystal structure is built of infinite zigzag-like chains of the Ru and Ge atoms, propagating along the [010] direction. The essential feature is a very short interatomic distance between the Ce1 atoms and the Ru atoms being equal to 2.226(2) A, while the Ce2–Ru distance is of regular length. This structural property gives rise to distinctive physical behavior of the compound that exhibits the coexistence of valence fluctuations associated with unstable 4f shell of the Ce1 ions and a long-range magnetic ordering that emerges in the Ce2 ions sublattice. As revealed by means of magnetization, heat capacity and electrical resistivity measurements, Ce2RuGe orders antiferromagnetically at TN = 12.0(1) K, and becomes ferromagnetic below TC = 8.5(3) K.

Novel Ce-rich phases Ce 4 RuAl and Ce 23 Ru 7+ x Al 4- x (0 ≤ x ≤ 2.97) were found in the systematic investigation of the ternary Ce-Ru-Al system. Both compounds were investigated by scanning electron microscopy, EDX spectroscopy and X-ray diffraction methods. The Ce 4 RuAl compound crystallizes with a cubic structure of a Gd 4 RhIn type with lattice parameter a = 13.7709(8) A (sp. gr. F -43 m , Z = 16). Its crystal structure was determined from single crystal X-ray data (R F = 0.0241 for 741 independent reflections). The Ce 23 Ru 7+ x Al 4- x structure was established by X-ray powder diffraction. This compound belongs to Pr 23 Ir 7 Mg 4 structure type, space group P 6 3 mc . Cell parameters of Ce 23 Ru 7+ x Al 4- x at x = 0.4 are: a = 9.8137(4) A, c = 22.2010(13) A. In both compounds Ce 4 RuAl and Ce 23 Ru 7+ x Al 4- x some of the Ce-Ru distances are short, equal to 2.630 A and 2.562 A, respectively. Crystal chemistry of these intermetallics is characterized by packing of non-linear layers in which the Ru-centered trigonal [Ce 6 ] prisms are connected via common vertices and edges, - similar to packing in the related Ce 7 Ru 3 and La 15 Rh 5 Cd 2 compounds.

The crystal structure of the novel Al-rich intermetallic phase Ce4Pt9Al13 was determined from single-crystal X-ray diffraction data and confirmed by powder X-ray diffraction. The compound crystallizes with its own structure type, which is a “site exchange” variant of the Ho4Ir13Ge9-type (Pearson symbol oP52, space group Pmmn, No. 59, Z = 2, lattice parameters: a = 4.1826(1) A, b = 11.4424(3) A, c = 19.8475(5) A, V = 949.88(7) A3). The magnetic properties of Ce4Pt9Al13 were determined in the temperature range 1.72–400 K. Down to the lowest temperatures studied, the compound shows a Curie-Weiss paramagnetic behavior with strong crystalline electric field contribution observed below about 200 K. The electrical conductivity in Ce4Pt9Al13 has metallic character, and at low temperatures it is governed by an interplay of strong crystal field and Kondo interactions.

Ternary intermetallic alloys Ce 2 Rh 3+x Ge 1-x (0 ≤ x ≤ 0.33) have been found to crystallize in a rhombohedral structure of the Mg 2 Ni 3 Si-type (space group R -3 m ). With varying the stoichiometry, the lattice parameters significantly vary from a = 5.5887(2) A, c = 11.9557(5) A (hexagonal setting) for x = 0 to a = 5.5127(2) A, c = 12.2790(5) A for x = 0.33, while the unit cell volume remains nearly unchanged. By means of magnetic susceptibility, heat capacity and electrical resistivity measurements, the Ce 2 Rh 3+x Ge 1-x alloys have been shown to be intermediate valence systems with highly unstable 4 f shell of Ce ions. Notably, the ferromagnetic ordering, claimed in the literature to coexist with the valence fluctuations in Ce 2 Rh 3 Ge, has been revealed to be an extrinsic effect due to impurity contribution.

A novel ternary intermetallic germanide CeIrGe 2 has been studied by means of x-ray diffraction, magnetization, specific heat and electrical resistivity measurements, performed in wide ranges of temperature and external magnetic fields. The compound crystallizes in an orthorhombic structure of the CeNiSi 2 -type (space group Cmcm ). It exhibits a Kondo lattice behavior and orders antiferromagnetically at 4 K.

Two novel ternary rare-earth aluminides, CePd 3 Al 2 and LaPd 3 Al 2 , were obtained by arc-melting the elements and subsequent annealing at 800 °C. Their crystal structures were determined from the single-crystal X-ray diffraction data. The compounds crystallize with their own structure type: space group Pnma , Z = 4, Pearson symbol oP 24, а = 7.491(2) A, b = 4.3575(17) A, ≿ = 13.123(4) A for CePd 3 Al 2 and а = 7.474(7) A, b = 4.3755(17) A, ≿ = 13.323(9) A for LaPd 3 Al 2 . The physical behavior of the Ce-based material was studied by means of magnetic, electrical resistivity and heat capacity measurements carried out down to 0.4 K. The compound was characterized as an antiferromagnetic heavy-fermion system with the Neel temperature T N = 1 K and the Kondo energy scale of about 2 K.

The new ternary intermetallic with high content of germanium, CeRuGe 5 , was found in the course of reinvestigation of the Ce-Ru-Ge system at 700 °C. The compound crystallizes in the tetragonal structure of new type (space group I 4/ mcm ) with the unit cell parameters: a = 6.1414(6) A, c = 13.751(3) A, Z = 4, Pearson symbol tI 28. The structure of CeRuGe 5 can be presented as [CeGe 3 ] and [RuGe 2 ] slabs alternating along the tetragonal c -axis. It is shown that the new structure of CeRuGe 5 and the known before structure of Sm 2 Ru 5 Ga 9 are derivatives from the common prototype – HoCoGa 5 . By means of magnetic, heat capacity and electrical transport measurements, the novel compound CeRuGe 5 was established to be a metallic Curie-Weiss paramagnet due to stable 4 f 1 electronic configuration of trivalent Ce ions. No intrinsic long-range magnetic ordering was found down to 1.7 K.

Phase relations in the ternary system Ce–Ir–Si have been established and the isothermal section at 950 °C was constructed based on X-ray powder diffraction, scanning electron microscopy, and electron probe microanalysis techniques on 83 alloys, which were prepared by arc melting under argon or powder reaction sintering. Among the 15 ternary compounds observed at 950 °C 8 phases have been reported earlier. Based on powder X-ray diffraction data the crystal structures for 6 new ternary phases were assigned to known structure types: τ6 – Ce3IrSi3 (Ta3B4-type), τ8 – Ce3Ir4Si4 (U3Ni4Si4-type), τ10 – Ce6Ir30Si19 (Sc6Co30Si19-type), τ12 – Ce2Ir12Si7 (Ho2Rh12As7-type), τ13 – Ce3Ir2−xSi2+x (Sm3Ir2Si2-type), and τ14 – Ce3Ir3Si2 (Ce3Rh3Si2-type). For another new compound τ1 – Ce4Ir27Si69 (at.%), which has homogeneity region along 27 at.% of Ir, the reflections were indexed in hexagonal lattice symmetry with cell parameters close to high-temperature IrSi3−x phase.

The crystal structure of Yb 2 PdGe 6 was studied by powder X-ray diffraction technique. The compound in both as-cast and annealed forms crystallizes with the orthorhombic structure of the Ce 2 GaGe 6 -type (space group Cmce ) that can be modelled as a sequence of AlB 2 -type slabs, quadrangular antiprismatic slabs, and distorted αPo-type slabs propagating along the crystallographic c direction. The low-temperature physical properties of Yb 2 PdGe 6 were determined by means of magnetic susceptibility and electrical resistivity measurements. The compound was characterized as an intermediate valent material because of a highly unstable 4 f shell of Yb ions.

A novel ternary compound Ce 3 RuSn 6 was synthesized as a single phase polycrystalline alloy. Its crystal structure was solved by direct methods and refined from the single crystal X-ray diffraction data down to R1 = 0.038 for 1021 independent reflections with I > 2σ(I) and 36 variable parameters. The compound crystallizes with an orthorhombic unit cell of the Yb 3 CoSn 6 type (space group Cmcm , lattice parameters: a = 4.6744 (4), b = 16.8542 (15), c = 13.3227 (12) A), in which Ce atoms occupy two independent crystallographic sites. Physical behavior in Ce 3 RuSn 6 was studied by means of magnetic susceptibility, electrical resistivity and heat capacity measurements, performed down to 0.4 K in magnetic fields up to 9 T. The compound exhibits ferromagnetic ordering below T C = 3 K. Its thermodynamic and electrical transport properties in the paramagnetic and ordered states are strongly influenced by Kondo effect with the characteristic temperature very close to T C .

New ternary intermetallic compound Ce2Ru2Al was prepared in polycrystalline form, and its crystal structure was determined from both powder and single crystal X-ray diffraction data. The aluminide was found to crystallize with an orthorhombic structure (space group Cmce) with the lattice parameters: a = 5.8914(4) A, b = 9.9603(6) A, and c = 6.9551(4) A. The derived unit cell is an ordered variant of the binary La2Ni3 type, where one of two Ni sites is fully occupied with Ru atoms, while another one accommodates Al atoms. The structure of Ce2Ru2Al can be regarded as a sequence of atomic layers normal to b-axis. The remarkable structural feature is a short distance between Ce and Ru atoms equal to 2.7816(4) A. Magnetic measurements revealed that Ce ions in Ce2Ru2Al possess unstable 4f shell that leads to intermediate valence behavior of the compound. Similar valence instability was observed before for other Ce intermetallics with short Ce–Ru bonds.

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 C 2/ m , lattice parameters a = 11.5702(12) A, b = 4.7529(5) A, c = 15.2414(16) A, β = 103.511(2)°, Z = 12. The structure was refined to R 1 = 0.034 for 1806 F 2 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 A, d Ce3 – Ru1 = 2.434 A and d Ce3 – Ru3 = 2.429 A.

The formation of novel ternary cerium germanide with the chemical composition Ce33.3Ir22.2Ge44.5 (at.%) was established. As derived from powder X-ray diffraction data, the compound crystallizes with two polymorphic modifications. The high-temperature modification, established for as-cast alloy, possesses a tetragonal ThSi2-type structure and can be named as Ce(IrxGe1-x)2, x = 0.32. The low-temperature modification forms in the course of heat treatment at 1073 K, crystallizes with an orthorhombic structure of its own type and can be labeled as Ce3Ir2-xGe4+x, x = 0.02. Both structures belong to the AlB2 structural family and are closely related to each other. In both modifications, statistical mixtures of Ir and Ge atoms occupy same crystallographic sites. As found by means of magnetization measurements, the two structural variants of Ce33.3Ir22.2Ge44.5 (at.%) exhibit very similar magnetic properties. Both polymorphs are Curie-Weiss paramagnets with strong crystalline electric field features observed at low temperatures.

The crystal structures of LaPd 2 Ge and LaPdGe 3 have been refined by X-ray diffraction on powdered polycrystalline samples. These ternaries crystallize in YPd 2 Si ( Pnma ) and BaNiSn 3 ( I 4 mm ) structure types, respectively. As revealed by electrical resistivity, thermoelectric power and specific heat measurements, the former compound is superconducting below 0.6 K, which is not the case for the latter one (at least down to 0.3 K). Moreover, LaPdGe 3 was found to be a typical metal in comparison to LaPd 2 Ge which is rather a semimetal.

The crystal structure of the novel intermetallic Yb ∼3 Pt ∼4 Si 6− x was determined by single crystal X-ray diffraction: space group P 2 1 / m (No. 11); a = 8.4560(3) A, b = 4.2109(2) A, c = 12.7864(5) A, β = 99.537(2)°, R F = 0.046, wR2 = 0.132. The title compound is a disordered variant of the Y 3 Pt 4 Ge 6 type. It is characterized by the intergrowth of slabs cut from the ThCr 2 Si 2 and YIrGe 2 types of structures.

The crystal structure of Dy 2 PdGe 6 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) A, V = 1398.8 A 3 , Z = 8, 1259 unique reflections with I > 2 σ ( I 0 ) in refinement (2 Θ max = 75.81°), down to R 1 = 0.029, w R 2 = 0.071. The title compound represents an ordered derivative from the Ce 2 GaGe 6 -type. The crystal structure can be presented as a sequence of the AlB 2 -type slabs, quadrangular antiprisms slabs, and distorted αPo-type slabs along the c direction. The atomic order in Dy 2 PdGe 6 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) A.

The crystal structure of the novel compound Ce 3 Rh 5 Si was solved by means of powder diffraction pattern analysis using the charge-flipping method. The refinements yielded the space group Pnma and the orthorhombic unit cell parameters: a = 1.52632(2) nm, b = 0.55092(1) nm, and c = 0.75302(1) nm. A characteristic feature of the crystal structure of Ce 3 Rh 5 Si are vertex-sharing [Rh 4 ] and [Rh 3 Si] tetrahedra, which form a three-dimensional framework with Ce atoms located inside truncated tetrahedral voids. The structure exhibits close relationship with those of CeRh 2 (MgCu 2 -type) and Ce 2 Rh 3 Si (Y 2 Rh 3 Si-type). Magnetic and electrical resistivity measurements of Ce 3 Rh 5 Si were performed down to 2 K. The compound was characterized as a Pauli paramagnet with metallic character of the electrical conductivity.

Polycrystalline samples of the intermetallic compounds Dy 2 PdGe 6 and La 2 PdGe 6 which crystallize in the orthorhombic structure ( Cmca space group) were studied by means of magnetic, electrical resistivity, specific heat and differential thermoelectric power measurements. The Dy-germanide is an antiferromagnet below 25(1) K and at low temperature and above magnetic fields of 3.5 T it exhibits a metamagnetic behaviour. Especially the specific heat measurements point to well-localized 4 f -electrons in this compound. Whereas the isostructural La-germanide is a nonmagnetic material taken here as a reference compound. A good overall fit of the resistivity to a general Bloch–Gruneisen formula indicates its metallic character in contrast to the Dy-germanide being a semimetallic-like conductor. For the latter compound in its ordered state the electrical resistvity, specific heat and thermoelectric power are dominated by electron–magnon scattering with antiferromagnetic spin-wave spectrum typical of anisotropic antiferromagnetic systems. The observed Schottky anomaly yields an assumed crystal field scheme of low-energy lying levels. Its thermoelectric power behaviour achieves medium positive values at high temperatures, indicating a hole domination in electrical transport properties. On the other hand, S ( T ) below T N for Dy- and in the whole temperatures measured for La-based compounds is negative, pointing to their electron carrier origin.

The crystal structure of the novel compound Yb3Pt23Si11 has been determined from powder X-ray diffraction data to be isotypic with cubic Ce3Pt23Si11 (space group F m 3 ¯ m ; a = 1.68052(5) nm). Magnetic susceptibility, electrical resistivity and heat capacity measurements, performed down to 0.4 K, revealed that Yb3Pt23Si11 is a moderately enhanced paramagnetic compound with fairly unstable 4f electronic shell.

Five novel cerium-based ternaries Ce2Rh3.1Si0.9 ,C e 4Rh12Si, Ce8Rh21.9Si3.1, CeRh1.82Si0.18 and CeRh3Si0.125 were studied by means of magnetic susceptibility and electrical resistivity measurements. All these phases were found to be Pauli paramagnets with metallic type of electrical conductivity.

Ternary intermetallic CeRu 0.88 In 2 was synthesized by arc-melting from elemental Ce, Ru, and In under an argon atmosphere. The crystal structure of CeRu 0.88 In 2 was determined from single-crystal X-ray diffraction data: a = 4.5449(11) A, b = 10.014(2) A and c = 7.6854(10) A; space group Cmcm , Z = 4, MgCuAl 2 type. The structure is formed of three-dimensional framework of [Ru 0.88 In 2 ], in the infinite pentagonal channels of which Ce atoms are disposed. Similar to the other known ternary compounds of the Ce–Ru–In system, CeRu 0.88 In 2 exhibits unusually short Ce–Ru contact equal to 2.530(4) A, which in addition is the shortest one in the raw of LTIn 2 compounds with MgCuAl 2 structure type (L = La, Ce, Pr, Nd, Sm, Eu, Gd, Yb; T = Rh, Pd, Au).

The ternary intermetallic Ce 16 Ru 8 In 37 was synthesized by arc-melting from elemental Ce, Ru, and In under an argon atmosphere. The crystal structure of Ce 16 Ru 8 In 37 was determined from the single-crystal X-ray diffraction data: a = 4.7451(1) A, b = 9.3518(2) A, c = 32.6162(7) A; space group Immm , Z = 1. The architecture of the crystal structure of Ce 16 Ru 8 In 37 is based on CeIn 3 units with cubic Cu 3 Au-type and can be presented as consisting of two different slabs: CeIn 3 -like slab of composition Ce 4 In 14.5 and a slab of composition Ce 4 Ru 4 In 4 .

Cerium ruthenium indides, Ce2Ru2In3 and Ce3Ru2In2, were synthesized from the pure elements by arc-melting. Both structures present a site exchange variant of a new structure type with different occupation of one crystallographic site: space group Pnma, Z = 4, oP28, with cell parameters a = 17.7054(4) A, b = 4.7144(1) A, c = 7.4072(1) A for Ce2Ru2In3, and a = 17.394(2) A, b = 4.9073(6) A, c = 7.669(1) A for Ce3Ru2In2 at room temperature. In the structures there are eight extremely short Ce–Ru contacts per unit cell: Ce1–Ru1 = 2.3225(8) A, Ce1–Ru2 = 2.3681(8) A in Ce2Ru2In3, and Ce1–Ru1 = 2.2345(9) A, Ce3–Ru2 = 2.2811(9) A in Ce3Ru2In2. Such contacts cause considerable distortion of coordination polyhedra of all atoms and reduce cell parameter a by 1 A when compared to the parent NdRh2Sn4 structure.

The ternary intermetallic compounds Ce 0.67 Pt 2 Al 5 ( I ) and Ce 1.33 Pt 3 Al 8 ( II ) were synthesized in the Ce–Pt–Al system by the reaction of elemental Ce, Pt, and Al in an arc furnace under an argon atmosphere. The crystal structures of I and II were determined from single-crystal X-ray diffraction data. The crystals are characterized by the following unit cell parameters: a = 4.3105(18) A, c = 16.494(5) A, space group P 6 3 / mmc , Z = 2 ( I ) and a = 4.361(2) A, c = 39.00(2) A, space group R 3 ¯ m , Z = 6 ( II ). Both compounds have structures with different packing of layers.

The interaction of the components in the Ce–Pt–Si system at 600 °C was investigated over the whole concentration range by X-ray powder and single crystal diffraction, DTA, and electron probe X-ray analysis. There are nine ternary compounds in the Ce–Pt–Si system. The crystal structures of eight of them were determined.

Phase equilibria in the Sm–{Pd,Pt}–{Si,Ge} systems were studied at 870 K, and intermetallic compounds containing 20 at.% Sm were characterized by physical–chemical analysis methods.

The crystal structure of the new intermetallide Ce 3 Pd 14 Ge 5 was investigated by X-ray monocrystal diffraction method. It is found that the elementary cell belongs to space group Pnma, Z =4, a =0.9033(2) nm, b =0.9082(2) nm, c =1.8142(2) nm.

Physico-chemical analysis techniques, including X-ray phase analysis and differential thermal analysis were employed for the characterisation of compounds including their melting temperature. The melting temperature of 23 RT2X2 compounds belonging to the CeGa2Al2 structure has been measured. The melting temperature of 19 RTX2 compounds belonging to the CeNiSi2 structure has been measured (LaCoSi2, LaNiSi2, CeFeSi2, CeCoSi2, CeNiSi2, SmCoSi2, SmNiSi2, ErCoSi2, ErNiSi2, TmCoSi2, TmNiSi2, LaCoGe2, LaNiGe2, CeFeGe2, CeCoGe2, CeNiGe2, SmFeGe2, SmCoGe2, SmNiGe2). It is established, that the new ternary compound SmCoSi2 belongs to the CeNiSi2 structure type (group Cmcm, a=0.4088(1) nm, b=1.6320(3) nm, c=0.4008(1) nm).

Copyright (c) 1997 Elsevier Science S.A. All rights reserved. A novel ternary compound Ce 3 Pt 23 Ge 11 crystallises in a new structure type with space group F 3m and a=1.71833(9) nm. Here we present the results of magnetic, electrical and specific heat measurements, obtained on the single crystal and polycrystalline samples. This compound is a metal with normal Ce 3+ magnetic behaviour. Although the specific heat at low temperatures rises rapidly to a large value of 2.5 J/Ce-mol K at 0.38 K, we have not detected any phase transition down to this temperature. Only in the temperature range 0.1-1 K a small decrease in the resistivity value can be detected with an inflection point at approximately 0.3 K.

The crystal structure of the new ternary silicide CePt 3 Si [space group P 4 mm , a =4.072(1) A, c =5.442(2) A, Z =1, V =90.25(5) A 3 , R =0.0437 for 153 structure factors] was determined from single-crystal X-ray diffraction. The compound belongs to the CePt 3 B structure type of intermetallic compounds.

The crystal structure of the compound CeRh 2 Si was studied by X-ray single crystal diffraction methods and refined to R F =0.038: space group Cmcm , a =4.0413(9) A, b =17.730(3) A, c =4.0675(9) A, V =291.45(10) A 3 , Z =4. The structure belongs to a structure type that can be considered as a site exchange variant of the known CeNiSi 2 structure type (CeSiRh 2 ) with slightly different axial ratios.

The crystal structure of the intermetallic compound Ce 3 Ru 4 Al 12 has been studied. The experiment was carried out using the X-ray single crystal diffraction technique. It was established that the structure belongs to the Gd 3 Ru 4 Al 12 structure type, which is related to the EuMg 5.2 type. Ce 3 Ru 4 Al 12 has the space group P6 3 /mmc, a = 8.8652(10) A, c = 9.5700(2) A, V = 651.4(2) A 3 , and Z = 2.

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.

The crystal structure of the compound Ce3Pt23Ge11 has been determined by X-ray analysis of a single crystal (Enraf-Nonius CAD-4 autodiffractometer, Mo Kα radiation, 276 independent reflections, R-factor 0.0735 in isotropic approximation). This structure has been found to belong to a new structural type: space group F 4 3m, a = 17.1833(9) A , Z = 8 . The coordination polyhedra of the cerium atoms are compressed cubes, those of platinum have eight or 10 apexes and those of germanium are either trigonal prisms with an additional atom or cubes. The magnetic properties of Ce3Pt23Ge11 at low temperatures (4–100 K) were investigated. A diffuse magnetic phase transition at around 10 K was detected.

The crystal structure of the compound Ce 7 Pd 4 Ge 2 has been determined by X-ray analysis of a single crystal (Dartch autodiffractometer, Mo Kα radiation, 1116 independent reflections, reliability factor R = 0.0491 in the anisotropic approximation). This structure has been found to belong to a new structural type: space group P2 1 /n, a = 9.315(2) A , b = 12.277(7) A , c = 12.698(3) A , β = 114.31(2)° , Z = 4. The coordination polyhedra of the cerium atoms have 15 and 17 apexes, those of palladium are trigonal prisms with three additional atoms and a tetragonal antiprism with one additional atom, and those of germanium are trigonal prisms with three additional atoms.

The crystal structure of the new intermetallic compound Ce 4 Pd 29 Si 14 , was determined by X-ray single-crystal diffraction method revealing space group Fm3m with a =1.8010(2) nm and Z =4.

The crystal structure of the new compound Ce 3 Pd 5 Si was investigated by X-ray single crystal diffraction method. The compound crystallizes in a new structure type, space group Imma Z =4, a =1.3027(4) nm, b =0.7377(4) nm, c =0.7580(4) nm.

The interaction of the components in the Er–Co–Pd system at 600°C was investigated over the composition range 0–50 at% of erbium by X-ray powder, metallography, electron probe microanalysis (EPMA), DTA and SEM. The isothermal section at 600°C was determined based on these results.

The crystal structure of the compound Ce 3 Pt 4 Ge 6 has been determined by X-ray analysis of a single crystal (Enraf-Nonius CAD-4 autodiffractometer, Mo Kα radiation, 208 independent reflections, R = 0.033 in the anisotropic approximation). This structure has been found to belong to a new structural type: space group Bmmb , a = 4.419(1) A , b = 4.422(1) A , c = 26.222(5) A , Z = 2 . The coordination polyhedra of cerium atoms have 19 and 21 apexes; those of platinum are tetragonal antiprisms with two additional atoms and trigonal prisms with four additional atoms; those of germanium are trigonal prisms with three additional atoms and distorted cubo-octahedra.

The isothermal section at 600°C of the Yb–Pt–Ge phase diagram was investigated using metallography, X-ray powder diffraction and electron probe microanalysis. Only one binary compound, Yb 3 Ge 5 , was found in the Yb–Ge system. In the ternary Yb–Pt–Ge system the formation of the three phases, Yb 2 PtGe 6 , YbPtGe 2 , and YbPtGe was observed. The crystal structures of these compounds were determined.

The crystal structure of the new intermetallic compound CePd 5 Ge 3 belongs to the YNi 5 Si 3 structure type, space group Pnma, Z =4, a =2.024(1) nm, b =0.4122(1) nm, c =0.7244(3) nm.