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Single-crystal investigation of the compound Sm2Ru3Si5
Journal of Alloys and Compounds 299 (2000) L6–L8
L
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Letter
Single-crystal investigation of the compound Sm 2 Ru 3 Si 5 a,c b, c c P. Salamakha , O. Sologub *, G. Bocelli , L. Righi a
b
` , Portugal Departamento de Quimica, Instituto Tecnologico e Nuclear, P-2686 -953, Sacavem CNRS-UPR2 O9, Groupe des Laboratoires de Thiais, 2 – 8 rue Henri Dunant, 94320 Thiais, France c Centro per la Strutturistica Diffirattometrica CNR, Viale delle Scienze, 43100 Parma, Italy Received 12 October 1999; accepted 3 November 1999
Abstract ˚ The crystal structure of the Sm 2 Ru 3 Si 5 compound was refined from single-crystal diffraction (P4 /mnc space group, a510.747(6) A, ˚ to R50.0194 for 496 reflections with I0 . 4s (I0 ). The compound belongs to a U 2 Mn 3 Si 5 -type structure. 2000 c55.695(3) A) Elsevier Science S.A. All rights reserved. Keywords: Crystal structure; Single-crystal X-ray diffraction; Samarium; Ruthenium; Silica
1. Introduction
2. Experimental details and results
Several series of isotypic compounds have been reported in the ternary rare earth metal–ruthenium–silicon systems (R, light rare earth element), i.e. RRu 2 Si 2 (CeGa 2 Al 2 structure type) [1,2], RRuSi 3 (BaNiSn 3 structure type) [3], RRu 3 Si 2 (LaRu 3 Si 2 structure type) [4–6], and RRuSi (PbFCl structure type) [7]. However, it appears that Sm does not form compounds isostructural to those formed by the other light rare earth elements. The NdRuSi 2 type of structure was found to exist for the RRuSi 2 compounds when R5La, Ce, Nd [8–10]. No data were reported for the samarium containing ruthenium silicide with 1:1:2 composition. In order to check for compound formation in the appropriate part of the concentration phase diagram of the Sm–Ru–Si system, synthesis and X-ray investigation of samples within the concentration regions 20–30 at.% Sm, 30–20 at.% Ru and 50 at.% Si were performed. In this paper we report on the X-ray single-crystal investigation of the Sm 2 Ru 3 Si 5 compound observed within the investigated concentration region.
A sample of nominal composition Sm 20 Ru 30 Si 50 was prepared from high-purity elements by arc melting under an argon atmosphere. The alloy was annealed at 870 K in an evacuated quartz tube for 2 weeks and quenched by submerging the ampoule in water. A single crystal was isolated from the surface of the alloy and measured using an automatic diffractometer (Philips PW1100) under the conditions listed in Table 1.
*Corresponding author. E-mail address: [email protected] (O. Sologub)
Table 1 Parameters for the single-crystal X-ray data collections Compound
Sm 2 Ru 3 Si 5
Space group ˚ Lattice parameters (A) a c ˚ 3) Cell volume (A Calculated density (g cm 23 ) Linear absorption coefficient (cm 21 ) 2umax Number of measured reflections Number of unique reflections Number of reflections with I0 . 4s (I0 ) hkl range Number of refined parameters R, wR2 Goodness-of-fit Structure solution program
P4 /mnc
0925-8388 / 00 / $ – see front matter 2000 Elsevier Science S.A. All rights reserved. PII: S0925-8388( 99 )00690-8
10.747(6) 5.695(3) 657.76 7.5 17 251.0 60.08 997 517 496 0 # h, k # 15, 0 # l # 10 31 0.0194, 0.0409 1.087 SHELXL-97
P. Salamakha et al. / Journal of Alloys and Compounds 299 (2000) L6 –L8
L7
Table 2 Atomic coordinates and equivalent isotropic displacement parameters for the Sm 2 Ru 3 Si 5 compound Atom
Wyckoff position
x
y
z
2 ˚ 2) Ueq. 310 (A
Sm Ru 1 Ru 2 Si 1 Si 2 Si 3
8h 4c 8h 8h 8g 4e
0.26396(6) 0 0.14562(9) 0.32035(31) 0.17348(24) 0
0.42654(6) 0.5 0.12495(9) 0.02201(32) 0.67348(24) 0
0 0 0 0 0.25 0.23003(82)
1.159924) 0.944(30) 1.045(27) 1.149(63) 2.662(98) 1.047(82)
Table 3 Anisotropic displacement parameters for the Sm 2 Ru 3 Si 5 compound Atom
˚ 2) U11 310 2 (A
˚ 2) U22 310 2 (A
˚ 2) U33 310 2 (A
˚ 2) U23 310 2 (A
˚ 2) U13 310 2 (A
˚ 2) U12 310 2 (A
Sm Ru 1 Ru 2 Si 1 Si 2 Si 3
1.05(3) 1.00(4) 1.05(4) 1.12(13) 1.90(10) 1.10(11)
1.38(3) 1.00(3) 1.03(5) 1.26(15) 1.90(10) 1.10(11)
1.02(4) 0.82(6) 1.04(4) 1.04(14) 4.18(26) 0.94(20)
0.00 0.00 0.00 0.00 1.74(13) 0.00
0.00 0.00 0.00 0.00 1.74(13) 0.00
0.0592) 20.01(4) 20.04(3) 0.07(1) 0.77(14) 0.000
The structure was solved in the space group P4 /mnc by means of direct methods, revealing the positions of all atoms applying the program SHELXS-86 [11]. The structure was refined using a full-matrix least-squares program using atomic scattering factors provided by the program package SHELXL-97 [12]. The absorption correction was performed with the assistance of the DIFABS program [13].
Table 4 ˚ and coordination numbers of Selected interatomic distances (d|3.5 A) atoms (CN) for the Sm 2 Ru 3 Si 5 compound Atom
˚ d (A)
CN
Atom
˚ d (A)
CN
Sm–Si 2 2Si 2 2Si 4 2Si 3 2Si 3 2Ru 2 Ru 1 2Ru
2.8397(39) 3.0389(18) 3.0442(27) 3.1426(31) 3.1647(20) 3.1835(15) 3.2708(16) 3.4818(22)
14 14 14 14 14 14 14 14
Si 1 –2Ru 1 Si 1 –2Ru 2 Si 1 –2Si 3 Si 1 –Sm Si 1 –2Sm
2.4105(28) 2.4538(39) 2.5387(39 2.8397(39) 3.0389(18)
9 9 9 9 9
Ru 1 –4Si 2 2Si 3 2Ru 1 4Sm
2.4 105(28) 2.6366(39) 2.8475(15) 3.2708(16)
12 12 12 12
Si 2 –2Ru 2 Si 2 –2Si 2 Si 2 –Ru 1 Si 2 –2Sm Si 2 –2Sm
2.4656(20) 2.5387(39) 2.6366(39) 3.1426(31) 3.1647(20)
9 9 9 9 9
Ru 2 –Si 2 2Si 3 2Si 4 Si 2 2Ru 2 2Sm Sm
2.4538(39) 2.4656(20) 2.4709(29 2.4849(37) 2.9162(21) 3.1835(15) 3.4818(22)
11 11 11 11 11 11 11
Si 3 –4Ru 2 Si 3 –Si 4 Si 3 –4Sm
2.4709(29) 2.7225(95) 3.0442(27)
9 9 9
The final structural data for the Sm 2 Ru 3 Si 5 compound are given in Tables 2 and 3; interatomic distances are presented in Table 4. The atomic coordinates were standardized using the program STIDY [14]. The interatomic distances for the Sm 2 Ru 3 Si 5 compound correspond to values that are characteristic for intermetallic compounds [15]. A detailed description of the U 2 Mn 3 Si 5 compound is presented in Ref [16]. According to the classification of intermetallic compounds offered by Krypyakevich [17], the structure belongs to class N 9 of intermetallic compounds, with a tetragonal antiprism as a coordination polyhedron for the smallest atom (Si).
Acknowledgements P.S. wishes to thank NATO for a fellowship in Portugal and Italy. The work of O.S. was supported by a NATO– CNRS grant.
References [1] A. Szytula, J. Leciejevich, Magnetic properties of ternary intermetallic compounds of the RT 2 X 2 type, in: K.A. Gschneidner, L. Eyring (Eds.), Handbook on the Physics and Chemistry of Rare Earths, Vol. 12, 1989, p. 133, Chapter 83. [2] R. Ballestracci, G. Astier, Compes rendus hebdomadaires des seances de l’Academie des Sciences, Ser. B: Sciences Physiques 286B (1978) 109. [3] W. Xian-Zhong, B. Lloret, W.L. Ng, B. Chevalier, J. Etourneau, P. Hagenmuller, Revue de Chimie Minerale 22 (1985) 711. [4] J.M. Vandenberg, H. Bars, Mat. Res. Bull. 15 (1980) 1493.
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P. Salamakha et al. / Journal of Alloys and Compounds 299 (2000) L6 –L8
[5] H. Bars, Mat. Res. Bull. 15 (1980) 1489. [6] C. Godart, L.C. Gupta, R.D. Parks, U. Rauschwalbe, U. Alheim, U. Gottwick, W. Lieke, F. Steglich, Annales de Chimie, Paris 9 (1984) 979. [7] R. Welter, G. Venturini, B. Malaman, E. Ressouche, J. Alloys Comp. 202 (1993) 165. [8] R. Welter, G. Venturini, B. Malaman, J. Alloys Comp. 185 (1992) 235. [9] K. Cenzual, R. Ye. Gladyshevskii, E. Parthe, Acta Crystallogr. C48 (1992) 225. [10] P.S. Salamakha, O.L. Sologub, Ja. Stepien-Damm, Yu.M. Prots’, O.I. Bodak, J. Alloys Comp. 244 (1996) 161. [11] G.M. Sheldrick, SHELXS-86, Program for Crystal Structure Determination, University of Gottingen, Germany, 1986.
[12] G.M. Sheldrick, SHELXS-97, Program for Crystal Structure Refinement, University of Gottingen, Germany, 1997. [13] N. Walker, O. Stewart, Acta Crystallogr. A39 (1983) 158. [14] E. Parthe, L. Gelato, B. Chabot, M. Penzo, K. Cenzual, R. Gladyshevskii, TYPIX. Standardized data and crystal chemical characterization of inorganic structure types, 8th Edition, Gmelin Handbook of Inorganic and Organometallic Chemistry, Vol. 1, Springer-Verlag, Berlin, 1993. [15] W.B. Pearson, in: Crystal Chemistry and Physics of Metals and Alloys, Vol. 1, Mir, Moskva, 1977, p. 420. [16] Ya.P. Yarmoluk, L.G. Akselrud, E.I. Gladyschevskii, Kristallografiya 22 (1977) 350. [17] P.I. Krypyakevych, in: Structure Types of Intermetallic Compounds, Nauka, Moscow, 1977, p. 287.
L
www.elsevier.com / locate / jallcom
Letter
Single-crystal investigation of the compound Sm 2 Ru 3 Si 5 a,c b, c c P. Salamakha , O. Sologub *, G. Bocelli , L. Righi a
b
` , Portugal Departamento de Quimica, Instituto Tecnologico e Nuclear, P-2686 -953, Sacavem CNRS-UPR2 O9, Groupe des Laboratoires de Thiais, 2 – 8 rue Henri Dunant, 94320 Thiais, France c Centro per la Strutturistica Diffirattometrica CNR, Viale delle Scienze, 43100 Parma, Italy Received 12 October 1999; accepted 3 November 1999
Abstract ˚ The crystal structure of the Sm 2 Ru 3 Si 5 compound was refined from single-crystal diffraction (P4 /mnc space group, a510.747(6) A, ˚ to R50.0194 for 496 reflections with I0 . 4s (I0 ). The compound belongs to a U 2 Mn 3 Si 5 -type structure. 2000 c55.695(3) A) Elsevier Science S.A. All rights reserved. Keywords: Crystal structure; Single-crystal X-ray diffraction; Samarium; Ruthenium; Silica
1. Introduction
2. Experimental details and results
Several series of isotypic compounds have been reported in the ternary rare earth metal–ruthenium–silicon systems (R, light rare earth element), i.e. RRu 2 Si 2 (CeGa 2 Al 2 structure type) [1,2], RRuSi 3 (BaNiSn 3 structure type) [3], RRu 3 Si 2 (LaRu 3 Si 2 structure type) [4–6], and RRuSi (PbFCl structure type) [7]. However, it appears that Sm does not form compounds isostructural to those formed by the other light rare earth elements. The NdRuSi 2 type of structure was found to exist for the RRuSi 2 compounds when R5La, Ce, Nd [8–10]. No data were reported for the samarium containing ruthenium silicide with 1:1:2 composition. In order to check for compound formation in the appropriate part of the concentration phase diagram of the Sm–Ru–Si system, synthesis and X-ray investigation of samples within the concentration regions 20–30 at.% Sm, 30–20 at.% Ru and 50 at.% Si were performed. In this paper we report on the X-ray single-crystal investigation of the Sm 2 Ru 3 Si 5 compound observed within the investigated concentration region.
A sample of nominal composition Sm 20 Ru 30 Si 50 was prepared from high-purity elements by arc melting under an argon atmosphere. The alloy was annealed at 870 K in an evacuated quartz tube for 2 weeks and quenched by submerging the ampoule in water. A single crystal was isolated from the surface of the alloy and measured using an automatic diffractometer (Philips PW1100) under the conditions listed in Table 1.
*Corresponding author. E-mail address: [email protected] (O. Sologub)
Table 1 Parameters for the single-crystal X-ray data collections Compound
Sm 2 Ru 3 Si 5
Space group ˚ Lattice parameters (A) a c ˚ 3) Cell volume (A Calculated density (g cm 23 ) Linear absorption coefficient (cm 21 ) 2umax Number of measured reflections Number of unique reflections Number of reflections with I0 . 4s (I0 ) hkl range Number of refined parameters R, wR2 Goodness-of-fit Structure solution program
P4 /mnc
0925-8388 / 00 / $ – see front matter 2000 Elsevier Science S.A. All rights reserved. PII: S0925-8388( 99 )00690-8
10.747(6) 5.695(3) 657.76 7.5 17 251.0 60.08 997 517 496 0 # h, k # 15, 0 # l # 10 31 0.0194, 0.0409 1.087 SHELXL-97
P. Salamakha et al. / Journal of Alloys and Compounds 299 (2000) L6 –L8
L7
Table 2 Atomic coordinates and equivalent isotropic displacement parameters for the Sm 2 Ru 3 Si 5 compound Atom
Wyckoff position
x
y
z
2 ˚ 2) Ueq. 310 (A
Sm Ru 1 Ru 2 Si 1 Si 2 Si 3
8h 4c 8h 8h 8g 4e
0.26396(6) 0 0.14562(9) 0.32035(31) 0.17348(24) 0
0.42654(6) 0.5 0.12495(9) 0.02201(32) 0.67348(24) 0
0 0 0 0 0.25 0.23003(82)
1.159924) 0.944(30) 1.045(27) 1.149(63) 2.662(98) 1.047(82)
Table 3 Anisotropic displacement parameters for the Sm 2 Ru 3 Si 5 compound Atom
˚ 2) U11 310 2 (A
˚ 2) U22 310 2 (A
˚ 2) U33 310 2 (A
˚ 2) U23 310 2 (A
˚ 2) U13 310 2 (A
˚ 2) U12 310 2 (A
Sm Ru 1 Ru 2 Si 1 Si 2 Si 3
1.05(3) 1.00(4) 1.05(4) 1.12(13) 1.90(10) 1.10(11)
1.38(3) 1.00(3) 1.03(5) 1.26(15) 1.90(10) 1.10(11)
1.02(4) 0.82(6) 1.04(4) 1.04(14) 4.18(26) 0.94(20)
0.00 0.00 0.00 0.00 1.74(13) 0.00
0.00 0.00 0.00 0.00 1.74(13) 0.00
0.0592) 20.01(4) 20.04(3) 0.07(1) 0.77(14) 0.000
The structure was solved in the space group P4 /mnc by means of direct methods, revealing the positions of all atoms applying the program SHELXS-86 [11]. The structure was refined using a full-matrix least-squares program using atomic scattering factors provided by the program package SHELXL-97 [12]. The absorption correction was performed with the assistance of the DIFABS program [13].
Table 4 ˚ and coordination numbers of Selected interatomic distances (d|3.5 A) atoms (CN) for the Sm 2 Ru 3 Si 5 compound Atom
˚ d (A)
CN
Atom
˚ d (A)
CN
Sm–Si 2 2Si 2 2Si 4 2Si 3 2Si 3 2Ru 2 Ru 1 2Ru
2.8397(39) 3.0389(18) 3.0442(27) 3.1426(31) 3.1647(20) 3.1835(15) 3.2708(16) 3.4818(22)
14 14 14 14 14 14 14 14
Si 1 –2Ru 1 Si 1 –2Ru 2 Si 1 –2Si 3 Si 1 –Sm Si 1 –2Sm
2.4105(28) 2.4538(39) 2.5387(39 2.8397(39) 3.0389(18)
9 9 9 9 9
Ru 1 –4Si 2 2Si 3 2Ru 1 4Sm
2.4 105(28) 2.6366(39) 2.8475(15) 3.2708(16)
12 12 12 12
Si 2 –2Ru 2 Si 2 –2Si 2 Si 2 –Ru 1 Si 2 –2Sm Si 2 –2Sm
2.4656(20) 2.5387(39) 2.6366(39) 3.1426(31) 3.1647(20)
9 9 9 9 9
Ru 2 –Si 2 2Si 3 2Si 4 Si 2 2Ru 2 2Sm Sm
2.4538(39) 2.4656(20) 2.4709(29 2.4849(37) 2.9162(21) 3.1835(15) 3.4818(22)
11 11 11 11 11 11 11
Si 3 –4Ru 2 Si 3 –Si 4 Si 3 –4Sm
2.4709(29) 2.7225(95) 3.0442(27)
9 9 9
The final structural data for the Sm 2 Ru 3 Si 5 compound are given in Tables 2 and 3; interatomic distances are presented in Table 4. The atomic coordinates were standardized using the program STIDY [14]. The interatomic distances for the Sm 2 Ru 3 Si 5 compound correspond to values that are characteristic for intermetallic compounds [15]. A detailed description of the U 2 Mn 3 Si 5 compound is presented in Ref [16]. According to the classification of intermetallic compounds offered by Krypyakevich [17], the structure belongs to class N 9 of intermetallic compounds, with a tetragonal antiprism as a coordination polyhedron for the smallest atom (Si).
Acknowledgements P.S. wishes to thank NATO for a fellowship in Portugal and Italy. The work of O.S. was supported by a NATO– CNRS grant.
References [1] A. Szytula, J. Leciejevich, Magnetic properties of ternary intermetallic compounds of the RT 2 X 2 type, in: K.A. Gschneidner, L. Eyring (Eds.), Handbook on the Physics and Chemistry of Rare Earths, Vol. 12, 1989, p. 133, Chapter 83. [2] R. Ballestracci, G. Astier, Compes rendus hebdomadaires des seances de l’Academie des Sciences, Ser. B: Sciences Physiques 286B (1978) 109. [3] W. Xian-Zhong, B. Lloret, W.L. Ng, B. Chevalier, J. Etourneau, P. Hagenmuller, Revue de Chimie Minerale 22 (1985) 711. [4] J.M. Vandenberg, H. Bars, Mat. Res. Bull. 15 (1980) 1493.
L8
P. Salamakha et al. / Journal of Alloys and Compounds 299 (2000) L6 –L8
[5] H. Bars, Mat. Res. Bull. 15 (1980) 1489. [6] C. Godart, L.C. Gupta, R.D. Parks, U. Rauschwalbe, U. Alheim, U. Gottwick, W. Lieke, F. Steglich, Annales de Chimie, Paris 9 (1984) 979. [7] R. Welter, G. Venturini, B. Malaman, E. Ressouche, J. Alloys Comp. 202 (1993) 165. [8] R. Welter, G. Venturini, B. Malaman, J. Alloys Comp. 185 (1992) 235. [9] K. Cenzual, R. Ye. Gladyshevskii, E. Parthe, Acta Crystallogr. C48 (1992) 225. [10] P.S. Salamakha, O.L. Sologub, Ja. Stepien-Damm, Yu.M. Prots’, O.I. Bodak, J. Alloys Comp. 244 (1996) 161. [11] G.M. Sheldrick, SHELXS-86, Program for Crystal Structure Determination, University of Gottingen, Germany, 1986.
[12] G.M. Sheldrick, SHELXS-97, Program for Crystal Structure Refinement, University of Gottingen, Germany, 1997. [13] N. Walker, O. Stewart, Acta Crystallogr. A39 (1983) 158. [14] E. Parthe, L. Gelato, B. Chabot, M. Penzo, K. Cenzual, R. Gladyshevskii, TYPIX. Standardized data and crystal chemical characterization of inorganic structure types, 8th Edition, Gmelin Handbook of Inorganic and Organometallic Chemistry, Vol. 1, Springer-Verlag, Berlin, 1993. [15] W.B. Pearson, in: Crystal Chemistry and Physics of Metals and Alloys, Vol. 1, Mir, Moskva, 1977, p. 420. [16] Ya.P. Yarmoluk, L.G. Akselrud, E.I. Gladyschevskii, Kristallografiya 22 (1977) 350. [17] P.I. Krypyakevych, in: Structure Types of Intermetallic Compounds, Nauka, Moscow, 1977, p. 287.