Terbium (lithium zinc) distannide, TbLi1–xZnxSn2 (x = 0.2)

Stetskiv, A.; Tarasiuk, I.; Rozdzynska-Kielbik, B.; Oshchapovsky, I.; Pavlyuk, V.

doi:10.1107/S1600536812002103

inorganic compounds

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Volume 68| Part 2| February 2012| Page i16

doi:10.1107/S1600536812002103

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Terbium (lithium zinc) distannide, TbLi_1–xZn_xSn₂ (x = 0.2)

Andrij Stetskiv,^a Ivan Tarasiuk,^b ^* Beata Rozdzynska-Kielbik,^c Igor Oshchapovsky ^b and Volodymyr Pavlyuk ^b,^c

^aIvano-Frankivsk National Medical University, Department of Chemistry, Galytska str. 2, 76018 Ivano-Frankivsk, Ukraine, ^bDepartment of Inorganic Chemistry, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv, Ukraine, and ^cInstitute of Chemistry, Environment Protection and Biotechnology, Jan Dlugosz University, al. Armii Krajowej 13/15, 42-200 Czestochowa, Poland
^*Correspondence e-mail: tarasiuk.i@gmail.com

(Received 17 November 2011; accepted 17 January 2012; online 21 January 2012)

The new terbium (lithium zinc) distannide, TbLi_1–xZn_xSn₂ (x = 0.2) crystallizes in the orthorhombic CeNiSi₂ structure type with space group Cmcm and Pearson symbol oS16. Of the four independent 4c atom positions (m2m site symmetry), three are fully occupied by individual atoms (two by Sn and one by Tb atoms) and the fourth is occupied by Li and Zn atoms with a statistical distribution. The Tb coordination polyhedron is a 21-vertex pseudo-Frank–Kasper polyhedron. One Sn atom is enclosed in a tricapped trigonal prism, the second Sn atom is in a cuboctahedron and the statistically distributed (Li,Zn) site is in a tetragonal antiprism with one added atom. Electronic structure calculations were used for the elucidation of reasons for and the ability of mutual substitution of lithium and transition metals. Positive charge density was observed around the rare earth atom and the Li and Zn atoms, the negative charge density in the proximity of the Sn atoms.

Related literature

For general background, see: Andersen et al. (1986 ); Pavlyuk et al. (2009 ). For related structures, see: Pavlyuk & Bodak (1992a ,b ); Pavlyuk et al. (1991 , 1993 ). For isotypic structures, see: Pavlyuk et al. (1989 ).

Experimental

Crystal data

TbLi_0.8Zn_0.2Sn₂
M_r = 414.85
Orthorhombic, C m c m
a = 4.4495 (7) Å
b = 17.699 (3) Å
c = 4.3978 (7) Å
V = 346.33 (9) Å³
Z = 4
Mo Kα radiation
μ = 35.55 mm⁻¹
T = 293 K
0.08 × 0.04 × 0.02 mm

Data collection

Oxford Diffraction Xcalibur3 CCD diffractometer
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008 $[Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ) T_min = 0.344, T_max = 0.658
1198 measured reflections
261 independent reflections
190 reflections with I > 2σ(I)
R_int = 0.041

Refinement

R[F² > 2σ(F²)] = 0.027
wR(F²) = 0.066
S = 1.19
261 reflections
20 parameters
Δρ_max = 2.15 e Å⁻³
Δρ_min = −2.64 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 $[Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2008 $[Oxford Diffraction (2008). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812002103/fi2120sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812002103/fi2120Isup2.hkl

checkCIF report

Comment top

During the systematic investigation of alloys of the Tb–Li–Sn and Tb–Zn–Sn ternary systems the ternary compounds with the corresponding compositions TbLiSn₂ (Pavlyuk et al., 1989) and TbZnSn₂ (Pavlyuk et al., 2009) were found. According to the X-ray data, TbLiSn₂ crystallizes with orthorhombic symmetry (space group Cmcm, CeNiSi₂ structure type) and the TbZnSn₂ with tetragonal symmetry (space group P4/nmm, HfCuSi₂ structure type). Structural studies of the four-component alloys from TbLiSn₂–TbZnSn₂ sections indicate the existence of TbLi_1–_xZn_xSn₂ (x = 0 - 1/5) limited solid solution. In the ternary TbLiSn₂ compound lithium atoms occupy the same crystallographic position that the atoms of transition metal in the original CeNiSi₂ structure type. The same was observed previously when we studied RELiGe with the ZrNiAl type (Pavlyuk et al., 1991 and Pavlyuk et al., 1992a) and RE₃Li₂Ge₃ with Hf₃Ni₂Si₃ type (Pavlyuk & Bodak, 1992b). X-ray single-crystal study showed that the TbLi_1–_xZn_xSn₂ solid solution formed by the partial substitution of lithium atoms by zinc atoms in 4c site. The ability of lithium atoms to substitute the atoms of transition metals we observed previously studying solid solutions RELi_xCu_2–_xSi₂ and RELi_xCu_2–_xGe₂ (Pavlyuk et al., 1993).

The projection of the unit cell and coordination polyhedra of the atoms are shown in Fig. 1. The coordination polyhedra of atoms are: Tb1 – 21-vertex pseudo Frank-Kasper polyhedron [Tb(Zn,Li)₅Sn₁₀Tb₆], Sn1 – 9-vertex tricapped trigonal prism [Sn1(Li,Zn)Sn₂Tb₆], Sn2 – 12-vertex cuboctahedron [Sn2(Li,Zn)₄Sn₄Tb₄] and statistical mixture (Li,Zn) – 9-vertex tetragonal antiprism with one added atom [(Li,Zn)Sn₅Tb₄].

Formation of the same RELi_1–_xZn_xSn₂ solid solutions were observed with other rare earth metals, such as Gd, Dy, Ho and Y.

The electronic structure calculations using TB-LMTO-ASA (Andersen et al., 1986) program package were performed for the elucidation of reasons of the formation of solid solutions and the ability to mutual substitution of lithium and transition metals. The ordered model of RELiSn₂ ternary phase and hypothetical REZnSn₂ with CeNiSi₂ structure type were analyzed. Among the rare earth metals was taken yttrium, which has less number of electrons than majority of other rare earth metals.

According to the results of calculations in the both models the rare earth atoms donate their electrons to tin atoms. The lithium atoms (Fig. 2a) and zinc atoms (Fig. 2 b) also loses their electrons. So positive charge density in various scale can be observed around rare earth, lithium and zinc atoms and negative charge density is around tin atoms. Taking into account these data and also the closeness of the effective radius of zinc and lithium atoms in intermetallic compounds it can be concluded that nothing prevents their mutual substitution.

Related literature top

For general background, see: Andersen et al. (1986); Pavlyuk et al. (2009). For related structures, see: Pavlyuk & Bodak (1992a,b); Pavlyuk et al. (1991, 1993). For isostructural/isotypic structures, see: Pavlyuk et al. (1989).

Experimental top

Terbium, lithium, zinc and tin, all with a nominal purity more than 99.9 wt. %, were used as starting elements. First, the pieces of the pure metals with a stoichiometry Tb₂₅Li₂₀Zn₅Sn₅₀ were pressed into pellets, enclosed in a tantalum crucible and placed in a resistance furnace with a thermocouple controller. The sample was heated to 670 K at a rate of 5 K/min, maintained over a period of 48 h and then temperature was increased to 1070 K over a period of 10 h. The alloy was annealed at 670 K for 120 h and cooled slowly to room temperature. Small, good-quality single-crystals of the title compound were isolated from an alloy by mechanical fragmentation.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis CCD (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Unit cell projection and coordination polyhedra of atoms in the TbLi_1–_xZn_xSn₂ compound. Thermal ellipsoids are drawn at a 95% probability level.
	Fig. 2. The results of electron localization function calculations for ordered structure models of REZnSn₂ (a) and RELiSn₂ (b). ELF map drawn at z = 0.

terbium (lithium zinc) distannide top

Crystal data top

TbLi_0.8Zn_0.2Sn₂	F(000) = 693.6
M_r = 414.85	D_x = 7.956 Mg m⁻³
Orthorhombic, Cmcm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2c 2	Cell parameters from 261 reflections
a = 4.4495 (7) Å	θ = 4.6–28.0°
b = 17.699 (3) Å	µ = 35.55 mm⁻¹
c = 4.3978 (7) Å	T = 293 K
V = 346.33 (9) Å³	Prism, metallic dark grey
Z = 4	0.08 × 0.04 × 0.02 mm

Data collection top

Oxford Diffraction Xcalibur3 CCD diffractometer	261 independent reflections
Radiation source: fine-focus sealed tube	190 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.041
Detector resolution: 0 pixels mm^-1	θ_max = 28.0°, θ_min = 4.6°
ω scans	h = −5→5
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008)	k = −17→23
T_min = 0.344, T_max = 0.658	l = −5→5
1198 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.027	w = 1/[σ²(F_o²) + (0.0272P)² + 2.6711P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.066	(Δ/σ)_max < 0.001
S = 1.19	Δρ_max = 2.15 e Å⁻³
261 reflections	Δρ_min = −2.64 e Å⁻³
20 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0039 (4)

Crystal data top

TbLi_0.8Zn_0.2Sn₂	V = 346.33 (9) Å³
M_r = 414.85	Z = 4
Orthorhombic, Cmcm	Mo Kα radiation
a = 4.4495 (7) Å	µ = 35.55 mm⁻¹
b = 17.699 (3) Å	T = 293 K
c = 4.3978 (7) Å	0.08 × 0.04 × 0.02 mm

Data collection top

Oxford Diffraction Xcalibur3 CCD diffractometer	261 independent reflections
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008)	190 reflections with I > 2σ(I)
T_min = 0.344, T_max = 0.658	R_int = 0.041
1198 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.027	20 parameters
wR(F²) = 0.066	0 restraints
S = 1.19	Δρ_max = 2.15 e Å⁻³
261 reflections	Δρ_min = −2.64 e Å⁻³

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Tb1	0.0000	0.39911 (5)	0.2500	0.0156 (4)
Sn1	0.0000	0.06101 (10)	0.2500	0.0296 (6)
Sn2	0.0000	0.75076 (8)	0.2500	0.0274 (6)
Zn	0.0000	0.1960 (5)	0.2500	0.022 (3)	0.198 (11)
Li	0.0000	0.1960 (5)	0.2500	0.022 (3)	0.80

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Tb1	0.0152 (5)	0.0167 (5)	0.0149 (6)	0.000	0.000	0.000
Sn1	0.0132 (8)	0.0638 (16)	0.0119 (9)	0.000	0.000	0.000
Sn2	0.0180 (8)	0.0423 (14)	0.0220 (10)	0.000	0.000	0.000
Zn	0.019 (5)	0.024 (5)	0.022 (6)	0.000	0.000	0.000
Li	0.019 (5)	0.024 (5)	0.022 (6)	0.000	0.000	0.000

Geometric parameters (Å, º) top

Tb1—Sn1ⁱ	3.2067 (6)	Sn2—Li^viii	2.392 (4)
Tb1—Sn1ⁱⁱ	3.2067 (6)	Sn2—Zn^viii	2.392 (4)
Tb1—Sn1ⁱⁱⁱ	3.2067 (6)	Sn2—Li^vii	2.392 (4)
Tb1—Sn1^iv	3.2067 (6)	Sn2—Zn^vii	2.392 (4)
Tb1—Sn2^v	3.4414 (13)	Sn2—Li^xi	2.427 (4)
Tb1—Sn2^vi	3.4414 (13)	Sn2—Zn^xi	2.427 (4)
Tb1—Sn2^vii	3.4454 (14)	Sn2—Li^xii	2.427 (4)
Tb1—Sn2^viii	3.4454 (14)	Sn2—Zn^xii	2.427 (4)
Tb1—Liⁱⁱ	3.552 (4)	Sn2—Sn2^xiii	3.1282 (4)
Tb1—Znⁱⁱ	3.552 (4)	Sn2—Sn2^xiv	3.1282 (4)
Tb1—Liⁱ	3.552 (4)	Sn2—Sn2^xv	3.1282 (4)
Tb1—Znⁱ	3.552 (4)	Sn2—Sn2^xvi	3.1282 (4)
Sn1—Zn	2.389 (9)	Zn—Sn2^viii	2.392 (4)
Sn1—Sn1^ix	3.082 (3)	Zn—Sn2^vii	2.392 (4)
Sn1—Sn1^x	3.082 (3)	Zn—Sn2^vi	2.427 (4)
Sn1—Tb1ⁱ	3.2067 (6)	Zn—Sn2^v	2.427 (4)
Sn1—Tb1ⁱⁱ	3.2067 (6)	Zn—Tb1ⁱⁱ	3.552 (4)
Sn1—Tb1^iv	3.2067 (6)	Zn—Tb1ⁱ	3.552 (4)
Sn1—Tb1ⁱⁱⁱ	3.2067 (6)	Zn—Tb1ⁱⁱⁱ	3.552 (4)
Sn1—Tb1^v	3.6277 (15)	Zn—Tb1^iv	3.552 (4)
Sn1—Tb1^vi	3.6277 (15)

Sn1ⁱ—Tb1—Sn1ⁱⁱ	154.57 (8)	Li^viii—Sn2—Zn^viii	0.0
Sn1ⁱ—Tb1—Sn1ⁱⁱⁱ	87.86 (2)	Li^viii—Sn2—Li^vii	133.6 (4)
Sn1ⁱⁱ—Tb1—Sn1ⁱⁱⁱ	86.59 (2)	Zn^viii—Sn2—Li^vii	133.6 (4)
Sn1ⁱ—Tb1—Sn1^iv	86.59 (2)	Li^viii—Sn2—Zn^vii	133.6 (4)
Sn1ⁱⁱ—Tb1—Sn1^iv	87.86 (2)	Zn^viii—Sn2—Zn^vii	133.6 (4)
Sn1ⁱⁱⁱ—Tb1—Sn1^iv	154.57 (8)	Li^vii—Sn2—Zn^vii	0.0 (4)
Sn1ⁱ—Tb1—Sn2^v	128.06 (4)	Li^viii—Sn2—Li^xi	99.05 (15)
Sn1ⁱⁱ—Tb1—Sn2^v	73.71 (3)	Zn^viii—Sn2—Li^xi	99.05 (15)
Sn1ⁱⁱⁱ—Tb1—Sn2^v	73.71 (3)	Li^vii—Sn2—Li^xi	99.05 (15)
Sn1^iv—Tb1—Sn2^v	128.06 (4)	Zn^vii—Sn2—Li^xi	99.05 (15)
Sn1ⁱ—Tb1—Sn2^vi	73.71 (3)	Li^viii—Sn2—Zn^xi	99.05 (15)
Sn1ⁱⁱ—Tb1—Sn2^vi	128.06 (4)	Zn^viii—Sn2—Zn^xi	99.05 (15)
Sn1ⁱⁱⁱ—Tb1—Sn2^vi	128.06 (4)	Li^vii—Sn2—Zn^xi	99.05 (15)
Sn1^iv—Tb1—Sn2^vi	73.71 (3)	Zn^vii—Sn2—Zn^xi	99.05 (15)
Sn2^v—Tb1—Sn2^vi	80.55 (4)	Li^xi—Sn2—Zn^xi	0.0
Sn1ⁱ—Tb1—Sn2^vii	127.38 (4)	Li^viii—Sn2—Li^xii	99.05 (15)
Sn1ⁱⁱ—Tb1—Sn2^vii	74.44 (3)	Zn^viii—Sn2—Li^xii	99.05 (15)
Sn1ⁱⁱⁱ—Tb1—Sn2^vii	127.38 (4)	Li^vii—Sn2—Li^xii	99.05 (15)
Sn1^iv—Tb1—Sn2^vii	74.44 (3)	Zn^vii—Sn2—Li^xii	99.05 (15)
Sn2^v—Tb1—Sn2^vii	54.030 (13)	Li^xi—Sn2—Li^xii	132.9 (4)
Sn2^vi—Tb1—Sn2^vii	54.030 (13)	Zn^xi—Sn2—Li^xii	132.9 (4)
Sn1ⁱ—Tb1—Sn2^viii	74.44 (3)	Li^viii—Sn2—Zn^xii	99.05 (15)
Sn1ⁱⁱ—Tb1—Sn2^viii	127.38 (4)	Zn^viii—Sn2—Zn^xii	99.05 (15)
Sn1ⁱⁱⁱ—Tb1—Sn2^viii	74.44 (3)	Li^vii—Sn2—Zn^xii	99.05 (15)
Sn1^iv—Tb1—Sn2^viii	127.38 (4)	Zn^vii—Sn2—Zn^xii	99.05 (15)
Sn2^v—Tb1—Sn2^viii	54.030 (13)	Li^xi—Sn2—Zn^xii	132.9 (4)
Sn2^vi—Tb1—Sn2^viii	54.030 (13)	Zn^xi—Sn2—Zn^xii	132.9 (4)
Sn2^vii—Tb1—Sn2^viii	79.32 (4)	Li^xii—Sn2—Zn^xii	0.0 (4)
Sn1ⁱ—Tb1—Liⁱⁱ	164.43 (14)	Li^viii—Sn2—Sn2^xiii	130.50 (8)
Sn1ⁱⁱ—Tb1—Liⁱⁱ	41.00 (13)	Zn^viii—Sn2—Sn2^xiii	130.50 (8)
Sn1ⁱⁱⁱ—Tb1—Liⁱⁱ	95.41 (3)	Li^vii—Sn2—Sn2^xiii	50.01 (8)
Sn1^iv—Tb1—Liⁱⁱ	96.57 (3)	Zn^vii—Sn2—Sn2^xiii	50.01 (8)
Sn2^v—Tb1—Liⁱⁱ	39.97 (9)	Li^xi—Sn2—Sn2^xiii	49.05 (7)
Sn2^vi—Tb1—Liⁱⁱ	92.49 (12)	Zn^xi—Sn2—Sn2^xiii	49.05 (7)
Sn2^vii—Tb1—Liⁱⁱ	40.55 (9)	Li^xii—Sn2—Sn2^xiii	130.43 (9)
Sn2^viii—Tb1—Liⁱⁱ	91.74 (12)	Zn^xii—Sn2—Sn2^xiii	130.43 (9)
Sn1ⁱ—Tb1—Znⁱⁱ	164.43 (14)	Li^viii—Sn2—Sn2^xiv	50.01 (8)
Sn1ⁱⁱ—Tb1—Znⁱⁱ	41.00 (13)	Zn^viii—Sn2—Sn2^xiv	50.01 (8)
Sn1ⁱⁱⁱ—Tb1—Znⁱⁱ	95.41 (3)	Li^vii—Sn2—Sn2^xiv	130.50 (8)
Sn1^iv—Tb1—Znⁱⁱ	96.57 (3)	Zn^vii—Sn2—Sn2^xiv	130.50 (8)
Sn2^v—Tb1—Znⁱⁱ	39.97 (9)	Li^xi—Sn2—Sn2^xiv	130.43 (9)
Sn2^vi—Tb1—Znⁱⁱ	92.49 (12)	Zn^xi—Sn2—Sn2^xiv	130.43 (9)
Sn2^vii—Tb1—Znⁱⁱ	40.55 (9)	Li^xii—Sn2—Sn2^xiv	49.05 (7)
Sn2^viii—Tb1—Znⁱⁱ	91.74 (12)	Zn^xii—Sn2—Sn2^xiv	49.05 (7)
Liⁱⁱ—Tb1—Znⁱⁱ	0.0 (3)	Sn2^xiii—Sn2—Sn2^xiv	179.01 (11)
Sn1ⁱ—Tb1—Liⁱ	41.00 (13)	Li^viii—Sn2—Sn2^xv	50.01 (8)
Sn1ⁱⁱ—Tb1—Liⁱ	164.43 (14)	Zn^viii—Sn2—Sn2^xv	50.01 (8)
Sn1ⁱⁱⁱ—Tb1—Liⁱ	96.57 (3)	Li^vii—Sn2—Sn2^xv	130.50 (8)
Sn1^iv—Tb1—Liⁱ	95.41 (3)	Zn^vii—Sn2—Sn2^xv	130.50 (8)
Sn2^v—Tb1—Liⁱ	92.49 (12)	Li^xi—Sn2—Sn2^xv	49.05 (7)
Sn2^vi—Tb1—Liⁱ	39.97 (9)	Zn^xi—Sn2—Sn2^xv	49.05 (7)
Sn2^vii—Tb1—Liⁱ	91.74 (12)	Li^xii—Sn2—Sn2^xv	130.43 (9)
Sn2^viii—Tb1—Liⁱ	40.55 (9)	Zn^xii—Sn2—Sn2^xv	130.43 (9)
Liⁱⁱ—Tb1—Liⁱ	123.4 (3)	Sn2^xiii—Sn2—Sn2^xv	89.326 (13)
Znⁱⁱ—Tb1—Liⁱ	123.4 (3)	Sn2^xiv—Sn2—Sn2^xv	90.665 (13)
Sn1ⁱ—Tb1—Znⁱ	41.00 (13)	Li^viii—Sn2—Sn2^xvi	130.50 (8)
Sn1ⁱⁱ—Tb1—Znⁱ	164.43 (14)	Zn^viii—Sn2—Sn2^xvi	130.50 (8)
Sn1ⁱⁱⁱ—Tb1—Znⁱ	96.57 (3)	Li^vii—Sn2—Sn2^xvi	50.01 (8)
Sn1^iv—Tb1—Znⁱ	95.41 (3)	Zn^vii—Sn2—Sn2^xvi	50.01 (8)
Sn2^v—Tb1—Znⁱ	92.49 (12)	Li^xi—Sn2—Sn2^xvi	130.43 (9)
Sn2^vi—Tb1—Znⁱ	39.97 (9)	Zn^xi—Sn2—Sn2^xvi	130.43 (9)
Sn2^vii—Tb1—Znⁱ	91.74 (12)	Li^xii—Sn2—Sn2^xvi	49.05 (7)
Sn2^viii—Tb1—Znⁱ	40.55 (9)	Zn^xii—Sn2—Sn2^xvi	49.05 (7)
Liⁱⁱ—Tb1—Znⁱ	123.4 (3)	Sn2^xiii—Sn2—Sn2^xvi	90.665 (13)
Znⁱⁱ—Tb1—Znⁱ	123.4 (3)	Sn2^xiv—Sn2—Sn2^xvi	89.326 (13)
Liⁱ—Tb1—Znⁱ	0.0 (3)	Sn2^xv—Sn2—Sn2^xvi	179.01 (11)
Zn—Sn1—Sn1^ix	134.48 (5)	Sn1—Zn—Sn2^viii	113.2 (2)
Zn—Sn1—Sn1^x	134.48 (5)	Sn1—Zn—Sn2^vii	113.2 (2)
Sn1^ix—Sn1—Sn1^x	91.03 (10)	Sn2^viii—Zn—Sn2^vii	133.6 (4)
Zn—Sn1—Tb1ⁱ	77.28 (4)	Sn1—Zn—Sn2^vi	113.5 (2)
Sn1^ix—Sn1—Tb1ⁱ	130.05 (5)	Sn2^viii—Zn—Sn2^vi	80.95 (15)
Sn1^x—Sn1—Tb1ⁱ	70.427 (15)	Sn2^vii—Zn—Sn2^vi	80.95 (15)
Zn—Sn1—Tb1ⁱⁱ	77.28 (4)	Sn1—Zn—Sn2^v	113.5 (2)
Sn1^ix—Sn1—Tb1ⁱⁱ	70.427 (15)	Sn2^viii—Zn—Sn2^v	80.95 (15)
Sn1^x—Sn1—Tb1ⁱⁱ	130.05 (5)	Sn2^vii—Zn—Sn2^v	80.95 (15)
Tb1ⁱ—Sn1—Tb1ⁱⁱ	154.57 (8)	Sn2^vi—Zn—Sn2^v	132.9 (4)
Zn—Sn1—Tb1^iv	77.28 (4)	Sn1—Zn—Tb1ⁱⁱ	61.72 (13)
Sn1^ix—Sn1—Tb1^iv	70.427 (15)	Sn2^viii—Zn—Tb1ⁱⁱ	139.08 (5)
Sn1^x—Sn1—Tb1^iv	130.05 (5)	Sn2^vii—Zn—Tb1ⁱⁱ	67.52 (6)
Tb1ⁱ—Sn1—Tb1^iv	86.59 (2)	Sn2^vi—Zn—Tb1ⁱⁱ	139.77 (5)
Tb1ⁱⁱ—Sn1—Tb1^iv	87.86 (2)	Sn2^v—Zn—Tb1ⁱⁱ	67.36 (6)
Zn—Sn1—Tb1ⁱⁱⁱ	77.28 (4)	Sn1—Zn—Tb1ⁱ	61.72 (13)
Sn1^ix—Sn1—Tb1ⁱⁱⁱ	130.05 (5)	Sn2^viii—Zn—Tb1ⁱ	67.52 (6)
Sn1^x—Sn1—Tb1ⁱⁱⁱ	70.427 (15)	Sn2^vii—Zn—Tb1ⁱ	139.08 (5)
Tb1ⁱ—Sn1—Tb1ⁱⁱⁱ	87.86 (2)	Sn2^vi—Zn—Tb1ⁱ	67.36 (6)
Tb1ⁱⁱ—Sn1—Tb1ⁱⁱⁱ	86.59 (2)	Sn2^v—Zn—Tb1ⁱ	139.77 (5)
Tb1^iv—Sn1—Tb1ⁱⁱⁱ	154.57 (8)	Tb1ⁱⁱ—Zn—Tb1ⁱ	123.4 (3)
Zn—Sn1—Tb1^v	142.173 (19)	Sn1—Zn—Tb1ⁱⁱⁱ	61.72 (13)
Sn1^ix—Sn1—Tb1^v	56.40 (4)	Sn2^viii—Zn—Tb1ⁱⁱⁱ	67.52 (6)
Sn1^x—Sn1—Tb1^v	56.40 (4)	Sn2^vii—Zn—Tb1ⁱⁱⁱ	139.08 (5)
Tb1ⁱ—Sn1—Tb1^v	126.82 (4)	Sn2^vi—Zn—Tb1ⁱⁱⁱ	139.77 (5)
Tb1ⁱⁱ—Sn1—Tb1^v	75.43 (3)	Sn2^v—Zn—Tb1ⁱⁱⁱ	67.36 (6)
Tb1^iv—Sn1—Tb1^v	126.82 (4)	Tb1ⁱⁱ—Zn—Tb1ⁱⁱⁱ	76.49 (11)
Tb1ⁱⁱⁱ—Sn1—Tb1^v	75.43 (3)	Tb1ⁱ—Zn—Tb1ⁱⁱⁱ	77.56 (11)
Zn—Sn1—Tb1^vi	142.173 (19)	Sn1—Zn—Tb1^iv	61.72 (13)
Sn1^ix—Sn1—Tb1^vi	56.40 (4)	Sn2^viii—Zn—Tb1^iv	139.08 (5)
Sn1^x—Sn1—Tb1^vi	56.40 (4)	Sn2^vii—Zn—Tb1^iv	67.52 (6)
Tb1ⁱ—Sn1—Tb1^vi	75.43 (3)	Sn2^vi—Zn—Tb1^iv	67.36 (6)
Tb1ⁱⁱ—Sn1—Tb1^vi	126.82 (4)	Sn2^v—Zn—Tb1^iv	139.77 (5)
Tb1^iv—Sn1—Tb1^vi	75.43 (3)	Tb1ⁱⁱ—Zn—Tb1^iv	77.56 (11)
Tb1ⁱⁱⁱ—Sn1—Tb1^vi	126.82 (4)	Tb1ⁱ—Zn—Tb1^iv	76.49 (11)
Tb1^v—Sn1—Tb1^vi	75.65 (4)	Tb1ⁱⁱⁱ—Zn—Tb1^iv	123.4 (3)

Symmetry codes: (i) −x+1/2, −y+1/2, −z+1; (ii) −x−1/2, −y+1/2, −z; (iii) −x−1/2, −y+1/2, −z+1; (iv) −x+1/2, −y+1/2, −z; (v) x−1/2, y−1/2, z; (vi) x+1/2, y−1/2, z; (vii) −x, −y+1, −z; (viii) −x, −y+1, −z+1; (ix) −x, −y, −z; (x) −x, −y, −z+1; (xi) x−1/2, y+1/2, z; (xii) x+1/2, y+1/2, z; (xiii) −x−1/2, −y+3/2, −z; (xiv) −x+1/2, −y+3/2, −z+1; (xv) −x−1/2, −y+3/2, −z+1; (xvi) −x+1/2, −y+3/2, −z.

Experimental details

Crystal data
Chemical formula	TbLi_0.8Zn_0.2Sn₂
M_r	414.85
Crystal system, space group	Orthorhombic, Cmcm
Temperature (K)	293
a, b, c (Å)	4.4495 (7), 17.699 (3), 4.3978 (7)
V (Å³)	346.33 (9)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	35.55
Crystal size (mm)	0.08 × 0.04 × 0.02

Data collection
Diffractometer	Oxford Diffraction Xcalibur3 CCD diffractometer
Absorption correction	Analytical (CrysAlis RED; Oxford Diffraction, 2008)
T_min, T_max	0.344, 0.658
No. of measured, independent and observed [I > 2σ(I)] reflections	1198, 261, 190
R_int	0.041
(sin θ/λ)_max (Å⁻¹)	0.659

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.027, 0.066, 1.19
No. of reflections	261
No. of parameters	20
Δρ_max, Δρ_min (e Å⁻³)	2.15, −2.64

Computer programs: CrysAlis CCD (Oxford Diffraction, 2008), CrysAlis RED (Oxford Diffraction, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2006).

Acknowledgements

Financial support from the Ministry of Education and Science, Youth and Sport of Ukraine (No. 0111U001089) is gratefully acknowledged.

References

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