Er₃₆Pt_102−xSi₃₂(x= 2.6), a new structure type of a ternary intermetallic silicide

Abstract

Key indicatorsSingle-crystal X-ray study T = 293 K Mean '(Er±Si) = 0.004 A Ê Disorder in main residue R factor = 0.049 wR factor = 0.135 Data-to-parameter ratio = 27.5For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e. # 2004 International Union of Crystallography Printed in Great Britain ± all rights reservedThe title erbium platinum silicide compound represents a new structure type of intermetallic silicide with platinum and a heavy rare earth element (Tb±Tm). Four atoms exhibit disorder. Coordination polyhedra of most of the Pt atoms are distorted cuboctahedra; coordination polyhedra of the silicon atoms are distorted trigonal prisms with three additional atoms capping the square faces. CommentWe have shown that intermetallic compounds RPt 3 Si of the light rare earths (R = La, Ce, Nd, Sm) crystallize with the CePt 3 B structure type (Sologub et al., 2002) et al., 2003). The compounds with approximate composition RPt 3 Si, where R is a heavy rare earth element (R = Tb±Tm), are found to belong to a new structure type. The present work reports the results of a crystal structure investigation of the ®rst member of this new structural family of ternary intermetallic silicides. A view of the structure is shown in Fig. 1. In the structure of the title compound, atoms Si1, Pt4 and Pt10 deviate from the ideal positions on the symmetry elements. To account for the

Crystal structures of RPt3−xSi1−y(R=Y, Tb, Dy, Ho, Er, Tm, Yb) studied by single crystal X-ray diffraction

“…The observed picture unambiguously defines a c-parameter of $0.41 nm. Consequently the crystal structure of Er 36 Pt 102-x Si 32 (x ¼ 2.61) (space group P4 2 /mnm, Z ¼ 1, a ¼ 1.86723(1), c ¼ 0.81734(1) nm), as previously reported by Tursina et al [5] with twice the c-parameter, is considered a polymorphic modification. The lattice parameters for YPt 3Àx Si 1Ày are close to those of DyPt 3Àx Si 1Ày , while the general trend of the cell dimensions within the rare earths series reflects the conventional lanthanoid contraction (see Fig.…”

“…New alloys of RPt 3Àx Si 1Ày (Tb, Dy, Ho, Er, Tm) of 1 g each were synthesized by arc-melting from high-purity elements (499.9 mass%) on a water-cooled copper hearth in an argon environment starting from nominal composition R 21.5 Pt 59. 5 Si 19.0 (at.%) in accordance with the composition derived earlier from a single crystal study of Y 18 Pt 50+x Si 16Àx and Dy 18 Pt 50+x Si 16Àx [6]. To ensure complete fusion, all alloys were re-melted three times.…”

“…Whilst the compounds with Y, Dy, Yb adopt tetragonal crystal structures with space group P4/mbm (no. 127) and similar atom distribution (parameters a 0 E1.870 and c 0 E0.4065 nm), the crystal structure of Er 36 Pt 102Àx Si 32 (x ¼ 2.61) [5] is of a unique type with a two-fold superstructure in direction of the c-axis in space group P4 2 /mnm (no. 136) and with unit cell dimensions a ¼ 1.86723 nm and c ¼ 0.81734 nmE2c 0 .…”

“…Attempts to synthesize the members of the series with the remaining rare earth metals, however, prompted compounds with compositions close to RPt 3 Si but with different crystal structures. Hitherto four intermetallics, Er 36 Pt 102Àx Si 32 (x ¼ 2.61) [5], Y 18 Pt 50+x Si 16Àx (x ¼ 0.28), Dy 18 Pt 50+x Si 16Àx (x ¼ 0.56) [6], and Yb 18 Pt 51. 1 Si 15.1 [7], were reported, which from X-ray single crystal studies were found to exhibit complicated disordered tetragonal crystal structures and a small but significant shift from the stoichiometric composition 1:3:1 (thus a formula RPt 3Àx Si 1Ày is used in the current article).…”

Magnetic and transport properties of CePt3Ge Kondo lattice in crystalline and sub-micron state

“…Recently, new ternary compounds RPt 3−x Si 1−y , x = 0.17-0.22, y = 0.11-0.16 (R = Y, Tb, Dy, Ho, Er, Tm, Yb) have been reported [16,17]. All members of the series adopt the same crystal structures (space group P4/mbm), which can be considered as a packing of four types of building blocks which derive from the CePt 3 B-type unit cell by various degrees of distortion and Pt, Si-defects.…”