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The new title compound is synthesized by repeated arc melting of stoichiometric mixtures of the elements.

Polycrystalline Ce2Ru2Al is prepared by arc melting of the elements and subsequent annealing (evacuated quartz ampoules, 823 K, 30 d).

CePd2Al2 (I), CePd3Al3 (II), CePd3.04Al2.96, CePd4Al4 (III), and CePd4.06Al3.94 are prepared by arc melting of the elements followed by annealing (evacuated quartz tubes, 1070 K, ≥ 30 d).

The title compound is unintentionally obtained by arc melting of the elements in a ratio pertaining to YbPtSi2 with 3 wt.% excess of Yb due to its high volatility.The crystal structure of the novel intermetallic is determined by single crystal XRD (space group P21/m, Z = 2) and found to be a disordered variant of the Y3Pt4Ge6 type characterized by the intergrowth of slabs cut from the ThCr2Si2 and YIrGe2 types of structures.

The new title compound is prepared by arc melting of the elements and its crystal structure is determined by powder XRD.

The title compound is prepared by arc melting of the elements and characterized by powder XRD and magnetic, electrical resistivity, and heat capacity measurements.

The new compounds CeRh1.82Si0.18, CeRh3Si0.125, Ce2Rh3.1Si0.9, Ce4Rh12Si, and Ce8Rh21.9Si3.1 are prepared by arc melting of the elements followed by annealing at 950 °C for two weeks.

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.

Two series of intermetallic alloys, RT2Si and RTSi2, have been synthesized from stoichiometric compositions. The crystal structures of EuPt1+xSi2−x (CeNiSi2-type), CeIr2Si (new structure type), YbPd2Si and YbPt2Si (both YPd2Si-type) have been elucidated from X-ray single crystal CCD data, which were confirmed by XPD experiments. The crystal structures of LaRh2Si and LaIr2Si (CeIr2Si-type), {La,Ce,Pr,Nd}AgSi2 (all TbFeSi2-type), and EuPt2Si (inverse CeNiSi2-type) were characterized by XPD data. RT2Si/RTSi2 compounds were neither detected in as-cast alloys Sc25Pt50Si25, Eu25Os25Si50 and Eu25Rh25Si50 nor after annealing at 900 °C. Instead, X-ray single crystal data prompted Eu2Os3Si5 (Sc2Fe3Si5-type) and EuRh2+xSi2−x (x=0.04, ThCr2Si2-type) as well as a new structure type for Sc2Pt3Si2 (own type).

Phase relations have been established in the ternary system Ce-Rh-Si for the isothermal section at 800 deg. C based on X-ray powder diffraction and EPMA on about 80 alloys, which were prepared by arc melting under argon or by powder reaction sintering. From the 25 ternary compounds observed at 800 deg. C 13 phases have been reported earlier. Based on XPD Rietveld refinements the crystal structures for 9 new ternary phases were assigned to known structure types. Structural chemistry of these compounds follows the characteristics already outlined for their prototype structures: tau{sub 7}-Ce{sub 3}RhSi{sub 3}, (Ba{sub 3}Al{sub 2}Ge{sub 2}-type), tau{sub 8}-Ce{sub 2}Rh{sub 3-x}Si{sub 3+x} (Ce{sub 2}Rh{sub 1.35}Ge{sub 4.65}-type), tau{sub 10}-Ce{sub 3}Rh{sub 4-x}Si{sub 4+x} (U{sub 3}Ni{sub 4}Si{sub 4}-type), tau{sub 11}-CeRh{sub 6}Si{sub 4} (LiCo{sub 6}P{sub 4}-type), tau{sub 13}-Ce{sub 6}Rh{sub 30}Si{sub 19.3} (U{sub 6}Co{sub 30}Si{sub 19}-type), tau{sub 18}-Ce{sub 4}Rh{sub 4}Si{sub 3} (Sm{sub 4}Pd{sub 4}Si{sub 3}-type), tau{sub 21}-CeRh{sub 2}Si (CeIr{sub 2}Si-type), tau{sub 22}-Ce{sub 2}Rh{sub 3+x}Si{sub 1-x} (Y{sub 2}Rh{sub 3}Ge-type) and tau{sub 24}-Ce{sub 8}(Rh{sub 1-x}Si{sub x}){sub 24}Si (Ce{sub 8}Pd{sub 24}Sb-type). For tau{sub 25}-Ce{sub 4}(Rh{sub 1-x}Si{sub x}){sub 12}Si a novel bcc structure was proposed from Rietveld analysis. Detailed crystal structure data were derived for tau{sub 3}-CeRhSi{sub 2} (CeNiSi{sub 2}-type) and tau{sub 6}-Ce{sub 2}Rh{sub 3}Si{sub 5} (U{submore » 2}Co{sub 3}Si{sub 5}-type) by X-ray single crystal experiments, confirming the structure types. The crystal structures of tau{sub 4}-Ce{sub 22}Rh{sub 22}Si{sub 56}, tau{sub 5}-Ce{sub 20}Rh{sub 27}Si{sub 53} and tau{sub 23}-Ce{sub 33.3}Rh{sub 58.2-55.2}Si{sub 8.5-11.5} are unknown. High temperature compounds with compositions Ce{sub 10}Rh{sub 51}Si{sub 33} (U{sub 10}Co{sub 51}Si{sub 33}-type) and CeRhSi (LaIrSi-type) have been observed in as-cast alloys but these phases do not participate in the phase equilibria at 800 deg. C. - Graphical abstract: Phase relations in the ternary system Ce-Rh-Si have been established for the isothermal section at 800 deg. C based on X-ray powder and single-crystal diffraction, metallography, SEM and EMPA techniques on about 80 alloys. 25 ternary compounds were observed.« less

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 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.

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 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.

Phase relations in the ternary system Ce–Pd–Si have been established for the isothermal section at 8001C 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 8001C. Atom order was determined by direct methods from X-ray single-crystal counter data for the crystal structures of t8—Ce3Pd4Si4 (U3Ni4Si4type, Immm; a ¼ 0.41618(1), b ¼ 0.42640(1), c ¼ 2.45744(7) nm), t16—Ce2Pd14Si (own structure type, P4/nmm; a ¼ 0.88832(2), c ¼ 0.69600(2) nm) and also for t18—CePd1� xSix (x ¼ 0.07; FeB-type, Pnma; a ¼ 0.74422(5), b ¼ 0.45548(3), c ¼ 0.58569(4) nm). Rietveld refinements established the atom arrangement in the structures of t5—Ce3PdSi3 (Ba3Al2Ge2-type, Immm; a ¼ 0.41207(1), b ¼ 0.43026(1), c ¼ 1.84069(4) nm) and t13—Ce3� xPd20+xSi6 (0rxr1, Co 20Al3B6-type, Fm3 ¯ m; a ¼ 1.21527(2) nm). The ternary compound Ce2Pd3Si3 (structure-type Ce2Rh1.35Ge4.65, Pmmn; a ¼ 0.42040(1), b ¼ 0.42247(1), c ¼ 1.72444(3) nm) was detected as a high-temperature compound, however, does not participate in the equilibria at 8001C. 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 Cecontent such as for t2—Ce(PdxSi1� x)2 (AlB2-derivative type), t6—Ce(PdxSi1� x)2 (ThSi2-type) and t7—CePd2� xSi2+x. The crystal structures of compounds t4—Ce� 8Pd� 46Si� 46, t12—Ce� 29Pd� 49Si� 22, t15—Ce� 22Pd� 67Si� 11, t17—Ce� 5Pd� 77Si� 18 and t18—CePd1� xSix (x� 0.1) are still unknown.

The crystal structures of ternary compounds RPt3−xSi1−y(R=Y, Tb, Dy, Ho, Er, Tm, Yb) have been elucidated from X-ray single crystal CCD data. All compounds are isotypic and crystallize in the tetragonal space group P4/mbm. The general formula RPt3−xSi1−y arises from defects: x≈0.20, y≈0.14. The crystal structure of RPt3−xSi1−y can be considered as a packing of four types of building blocks which derive from the CePt3B-type unit cell by various degrees of distortion and Pt, Si-defects.

Phase relations in the ternary system Ce–Pt–Si have been established for the isothermal section at 800 °C based on X-ray powder diffraction, metallography, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) techniques on about 120 alloys, which were prepared by various methods employing arc-melting under argon or powder reaction sintering. Nineteen ternary compounds were observed. Atom order in the crystal structures of τ18-Ce5(Pt,Si)4 (Pnma; a=0.77223(3) nm, b=1.53279(8) nm c=0.80054(5) nm), τ3-Ce2Pt7Si4 (Pnma; a=1.96335(8) nm, b=0.40361(4) nm, c=1.12240(6) nm) and τ10-CePtSi2 (Cmcm; a=0.42943(2) nm, b=1.67357(5) nm, c=0.42372(2) nm) was determined by direct methods from X-ray single-crystal CCD data and found to be isotypic with the Sm5Ge4-type, the Ce2Pt7Ge4-type and the CeNiSi2-type, respectively. Rietveld refinements established the atom arrangement in the structures of Pt3Si (Pt3Ge-type, C2/m, a=0.7724(2) nm, b=0.7767(2) nm, c=0.5390(2) nm, β=133.86(2)°), τ16-Ce3Pt5Si (Ce3Pd5Si-type, Imma, a=0.74025(8) nm, b=1.2951(2) nm, c=0.7508(1) nm) and τ17-Ce3PtSi3 (Ba3Al2Ge2-type, Immm, a=0.41065(5) nm, b=0.43221(5) nm, c=1.8375(3) nm). Phase equilibria in Ce–Pt–Si are characterised by the absence of cerium solubility in platinum silicides. Cerium silicides and cerium platinides, however, dissolve significant amounts of the third component, whereby random substitution of the almost equally sized atom species platinum and silicon is reflected in extended homogeneous regions at constant Ce content such as for τ13-Ce(PtxSi1−x)2, τ6-Ce2Pt3+xSi5−x or τ7-CePt2−xSi2+x.

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 crystal structures of the compounds CeRuAl and CeRhAl were studied by single crystal X-ray diffraction. Both compounds crystallize in the orthorhombic LaNiAl type with space group Pnma (No. 62) and are related to the structure types of hexagonal ZrNiAl and orthorhombic TiNiSi. Parameters for CeRuAl and CeRhAl are: a = 7.2057(2) A, b = 4.0589(1) A, c = 15.8728(5) A; R F = 0.023; a = 7.107(2) A, b = 4.2237(10) A, c = 15.965(3) A; R F = 0.032, respectively.

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 .

The ternary intermetallic compound CeRu 3− x Al 10+ x ( x = 0.17) crystallizes in the orthorhombic system, space group Imma , a = 4.2213(1) A, b = 12.5014(3) A, c = 17.6689(4) A, Z = 4. It is closely related to NdCo 3 Ga 9 and can be regarded as a substructure of U 2 Co 6 Al 19 . Trigonal prismatic and cuboctahedral coordination is typical for Al and Ru atoms, the coordination polyhedron of the Ce atom is a pentagonal prism with five additional atoms. The structure can be described as a 3D network of aluminium and ruthenium atoms, forming distorted pentagonal channels along [1 0 0], where the cerium atoms are located.

The crystal structures of the compounds Dy18Pt50+xSi16−x (x = 0.28) (I) and Y18Pt50+xSi16−x (x = 0.56) (II) have been investigated by means of single crystal techniques (Nonius KappaCCD diffractometer, ω- and φ-scans, Mo Kα radiation). Both compounds belong to a new structure type (space group P4/mbm, Z = 1, a = 18.7778(2) A, c = 4.0897(1) A (I) and a = 18.7777(3) A, c = 4.0891(1) A (II)) closely related to the Er36Pt102−xSi32 (x = 2.6) type of structure (space group P42/mnm, Z = 1, a = 18.6723 A, c = 8.1734 A). Coordination numbers for three crystallographically independent Dy and Y atoms are 18, 15 and 12 and for Pt atoms range from 9 to 12, distorted cuboctahedra being typical for most of the Pt-atom polyhedra. Triangular prisms with three additional atoms are characteristic for coordination polyhedra of silicon atoms. The peculiarity of the defects of the Pt and Si atom positions as well as the relationship with the Er36Pt102−xSi32 structure is discussed.

The new ternary indides CePd 2 In 4 and CePt 2 In 4 were synthesized by arc-melting of the elements and subsequent annealing at 770 K for 1 month. The crystal structure of both the compounds was refined from the single crystal X-ray data. CePd 2 In 4 and CePt 2 In 4 crystallize in the orthorhombic NdRh 2 Sn 4 -type structure (space group Pnma), a = 18.449(3) A, b = 4.5647(6) A, c = 7.4145(15) A, V = 624.4(2)A 3 , R F = 5.96% for CePd 2 In 4 , a = 18.460(4) A, b = 4.5299(13) A, c = 7.2670(16) A, V = 607.7(3) A 3 , R F = 7.47% for CePt 2 In 4 .

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.

The crystal structures of the new compounds Ce 2 Rh 12 Si 7 and Ce 6 Rh 30 Si 19 , extracted from an ingot of composition Ce 9.5 Rh 56.9 Si 33.6 , were investigated by X-ray single crystal diffraction methods. The title compounds crystallize in the hexagonal space group P 6 3 / m with unit cell parameters a =9.706(1) A, c =3.8394(3) A and a =15.698(2) A, c =3.8571(4) A, respectively. Ce 2 Rh 12 Si 7 and Ce 6 Rh 30 Si 19 represent members of a family of hexagonal structures with a short unit cell parameter c ≈3.7 A and with general formula R n ( n +1) T 6( n 2 +1) M 4 n 2 +3 , where R is the rare earth, T the transition metal, and M the element of the IV or V main group. Ce 2 Rh 12 Si 7 crystallizes with the Ho 2 Rh 12 As 7 type, ignoring the disordered arrangement of non-metal atoms on the c -axis. The structure of Ce 6 Rh 30 Si 19 is closely related to that of Sc 6 Co 30 Si 19 .