Neue übergangsmetallaluminide des calciums

Cordier, G.; Czech, E.; Ochmann, H.; Schäfer, Herbert

doi:10.1016/0022-5088(84)90215-7

Cited by 38 publications

(22 citation statements)

References 16 publications

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“…11 Structure solution by direct methods confirmed the arrangement of the heavy atoms analogous to that observed for Ca 3 Ni 7 B 2 10 (Table 2). The boron position was successfully detected from difference Fourier synthesis.…”

Section: Determination and Analysis Of Crystal Structuressupporting

confidence: 68%

“…As compared to the prototype Ca 3 Al 7 Cu 2 structure, 11 significant changes in the coordination sphere of atoms are observed for the CeCo 3 B 2 -type block: (i) the distance between the 3636 kagomé net formed by Al atoms is long (about 0.400 nm) in contrast to the corresponding distance between platinum atoms in Eu 3 Pt 7 B 2 ( d Pt1–Pt1 = 0.29959 nm), thus delivering a different shape of the coordination polyhedron of Ca; (ii) due to the larger atomic radius of copper with respect to B, the distance Ca–Cu of 0.324 nm is sufficient to indicate bonding interaction, thus increasing the coordination number of Ca to CN = 20 (Figure 4f) as compared to CN Eu2 = 14 in Eu 3 Pt 7 B 2 . In contrast to EuPt 4 B, in the present structure none of the atoms show significant anisotropy in their thermal vibration (Table 2).…”

Section: Determination and Analysis Of Crystal Structuresmentioning

confidence: 99%

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Structural and Physical Properties Diversity of New CaCu₅-Type Related Europium Platinum Borides

et al. 2013

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Three novel europium platinum borides have been synthesized by arc melting of constituent elements and subsequent annealing. They were characterized by X-ray powder and single-crystal diffraction: EuPt4B, CeCo4B type, P6/mmm, a = 0.56167(2) nm, c = 0.74399(3) nm; Eu3Pt7B2, Ca3Al7Cu2 type as an ordered variant of PuNi3, R3̅m, a = 0.55477(2) nm, c = 2.2896(1) nm; and Eu5Pt18B6–x, a new unique structure type, Fmmm, a = 0.55813(3) nm, b = 0.95476(5) nm, c = 3.51578(2) nm. These compounds belong to the CaCu5 family of structures, revealing a stacking sequence of CaCu5-type slabs with different structural units: CaCu5 and CeCo3B2 type in EuPt4B; CeCo3B2 and Laves MgCu2 type in Eu3Pt7B2; and CaCu5-, CeCo3B2-, and site-exchange ThCr2Si2-type slabs in Eu5Pt18B6–x. The striking motif in the Eu5Pt18B6–x structure is the boron-centered Pt tetrahedron [BPt4], which build chains running along the a axis and plays a decisive role in the structure arrangement by linking the terminal fragments of repeating blocks of fused Eu polyhedra. Physical properties of two compounds, EuPt4B and Eu3Pt7B2, were studied. Both compounds were found to order magnetically at 36 and 57 K, respectively. For EuPt4B a mixed-valence state of the Eu atom was confirmed via magnetic and specific heat measurements. Moreover, the Sommerfeld value of the specific heat of Eu3Pt7B2 was found to be extraordinarily large, on the order of 0.2 J/mol K2.

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Section: Determination and Analysis Of Crystal Structuressupporting

confidence: 68%

Section: Determination and Analysis Of Crystal Structuresmentioning

confidence: 99%

Structural and Physical Properties Diversity of New CaCu₅-Type Related Europium Platinum Borides

et al. 2013

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“…Since the transition metal atoms are of approximately the same size as the aluminum atoms, and since the substitution of alumi- num atoms by transition metal atoms is known for intermetallics with similar composition Ϫ e.g., in the many compounds with CaCr 2 Al 10 [16], CeMn 4 Al 8 [17], and DyFe 6 Al 6 [18Ϫ20] type structure; all of these are substitution variants (4) a) The positional parameters have been standardized with the program STRUCTURE TIDY [23]. Only minor deviations from the ideal occupancy values were observed for Y 3 Ru 4 Al 12 .…”

Section: Structure Refinementsmentioning

confidence: 99%

Ternary Rare Earth (R) Transition Metal AluminidesR3T4Al12 (T = Ru and Os) with Gd3Ru4Al12 Type Structure

Niermann

Jeitschko

2002

Z. anorg. allg. Chem.

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The isotypic intermetallic compounds R 3 Ru 4 Al 12 (R ϭ Y, Pr, Nd, Sm, GdϪTm) and R 3 Os 4 Al 12 (R ϭ Y, CeϪNd, Sm, GdϪTm) were prepared by reaction of the elemental components in an arc-melting furnace. Their crystal structure was determined from four-circle X-ray diffractometer data of Y 3 Ru 4 Al 12 : P6 3 /mmc, a ϭ 877.7(1) pm, c ϭ 952.3(1) pm, Z ϭ 2, R ϭ 0.028 for 361 structure factors and 28 variable parameters. It was also refined for Nd 3 Os 4 Al 12 (a ϭ 889.2(1) pm, c ϭ 960.3(1) pm, R ϭ 0.021 for 425 F values and 30 variables) and Gd 3 Os 4 Al 12 (a ϭ 884.7(1) pm, c ϭ 955.3(2) pm, R ϭ 0.020; 427 F values, 30 variables). The refinements of the occupancy parameters revealed mixed T/Al occupancy for some of the aluminum sites resulting in the compositions Y 3Inhaltsübersicht. Die isotypen intermetallischen Verbindungen R 3 Ru 4 Al 12 (R ϭ Y, Pr, Nd, Sm, GdϪTm) und R 3 Os 4 Al 12 (R ϭ Y, CeϪNd, Sm, GdϪTm) wurden durch Reaktion der Elemente im Lichtbogenofen hergestellt. Ihre Kristallstruktur wurde für Y 3 Ru 4 Al 12 mittels Röntgen-Vierkreis-Diffraktometerdaten bestimmt: P6 3 /mmc, a ϭ 877,7(1) pm, c ϭ 952,3(1) pm, Z ϭ 2, R ϭ 0,028 für 361 Strukturfaktoren und 28 variable Parameter. Sie wurde auch für Nd 3 Os 4 Al 12 (a ϭ 889,2(1) pm, c ϭ 960,3(1) pm, R ϭ 0,021 für 425 F-Werte und 30 Variable) und Gd 3 Os 4 Al 12 (a ϭ 884,7(1) pm, c ϭ 955,3(2) pm, R ϭ 0,020; 427 F-Werte, 30 Variable) verfeinert. Die Verfeinerung der Besetzungsparameter ergab gemischte T/Al-Besetzung für einige Aluminiumpositionen entsprechend der

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“…The crystal structure of the new aluminides GdRe2Alio and TbRe2Alio, determined for the ter bium compound represents a new structure type which, however, is closely related to the structures of Y bFe2 Al]o [3], LuRe2Alio [2], and to a lesser extent also to the CaCr2A l10 type structure [8 ] of the compounds L/7Re2Alio (Ln = Ce-Nd, Sm [2,9]. In Fig.…”

Section: Discussionmentioning

confidence: 96%

The Intermetallic Compounds GdRe₂Al₁₀ and TbRe₂Al₁₀, Crystallizing with a Stacking Variant of the YbFe₂Al₁₀ Type Structure

Fehrmann¹,

Jeitschko²

1999

Zeitschrift Für Naturforschung B

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The new compounds GdRe2Al10 and TbRe2Al10 were obtained in well-crystallized form by reaction of the elemental components with an excess of aluminum after dissolving the matrix in hydrochloric acid. They crystallize with a new structure type which has been determined for TbRe2Al10 from single-crystal X-ray data: Cmcm, a = 932.2(1), b = 1030.4(1 ), c = 1803.2(3)pm, Z = 8, R = 0.031 for 1159 structure factors and 77 variable parameters. Of the two terbium sites, one does not have full occupancy with terbium, however, it may have mixed Tb/Al occupancy. The resulting compositions are Tb0.948(5)Re2Al10 or Tb0.936(3)Re2Al10.064(3), respectively. The terbium atoms are coordinated by 4 Re and 16 Al atoms. The rhenium atoms are situated in distorted icosahedra formed by 2 Tb and 10 Al atoms. The nine different aluminum atoms have between 12 and 14 neighbors (1 or 2 Tb, 2 Re, and between 8 and 11 Al atoms). The structure may be viewed as consisting of two kinds of alternating layers. One of these is puckered, hexagonal close packed, with a mesh content of 4ReAl3; the other is planar and less densely packed. It has the mesh content 2TbAl4. The same kinds of atomic layers have been found in the structures of YbFe2Al10 and LuRe2Al10. Thus, the three structure types may be considered as stacking variants of each other. The tetragonal CaCr2Al10 (ordered ThMn12) type structure also belongs to this structural family, although the CaAl4 layers somewhat differ from the layers TbAl4, YbAl4, and LuAl4.

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Neue übergangsmetallaluminide des calciums

Cited by 38 publications

References 16 publications

Structural and Physical Properties Diversity of New CaCu₅-Type Related Europium Platinum Borides

Structural and Physical Properties Diversity of New CaCu₅-Type Related Europium Platinum Borides

Ternary Rare Earth (R) Transition Metal AluminidesR3T4Al12 (T = Ru and Os) with Gd3Ru4Al12 Type Structure

The Intermetallic Compounds GdRe₂Al₁₀ and TbRe₂Al₁₀, Crystallizing with a Stacking Variant of the YbFe₂Al₁₀ Type Structure

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Neue übergangsmetallaluminide des calciums

Cited by 38 publications

References 16 publications

Structural and Physical Properties Diversity of New CaCu5-Type Related Europium Platinum Borides

Structural and Physical Properties Diversity of New CaCu5-Type Related Europium Platinum Borides

Ternary Rare Earth (R) Transition Metal AluminidesR3T4Al12 (T = Ru and Os) with Gd3Ru4Al12 Type Structure

The Intermetallic Compounds GdRe2Al10 and TbRe2Al10, Crystallizing with a Stacking Variant of the YbFe2Al10 Type Structure

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Structural and Physical Properties Diversity of New CaCu₅-Type Related Europium Platinum Borides

Structural and Physical Properties Diversity of New CaCu₅-Type Related Europium Platinum Borides

The Intermetallic Compounds GdRe₂Al₁₀ and TbRe₂Al₁₀, Crystallizing with a Stacking Variant of the YbFe₂Al₁₀ Type Structure