Crystal structure of the mixed-metal tris­ulfide BaCu1/3Ta2/3S3

Bu, K.; He, J.; Wang, D.; Zheng, C.; Huang, F.

doi:10.1107/S2056989017005266

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Volume 73| Part 5| May 2017| Pages 713-715

https://doi.org/10.1107/S2056989017005266

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Crystal structure of the mixed-metal trisulfide BaCu_1/3Ta_2/3S₃

Kejun Bu,^a Jianqiao He,^a Dong Wang,^b Chong Zheng ^c ^* and Fuqiang Huang ^a ^*

^aState Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China, ^bSchool of Materials Science and Engineering, Shanghai University, Shangda Road, No. 99, Shanghai 200444, People's Republic of China, and ^cDepartment of Chemistry and Biochemistry, Northern Illinois University, USA
^*Correspondence e-mail: czheng@niu.edu, huangfq@mail.sic.ac.cn

Edited by M. Weil, Vienna University of Technology, Austria (Received 17 January 2017; accepted 6 April 2017; online 18 April 2017)

The mixed-metal title compound, BaCu_1/3Ta_2/3S₃ [barium copper(II) tantalum(V) trisulfide], was prepared through solid-state reactions. The crystal structure adopts the BaTaS₃ structure type and consists of face-sharing [MS₆] (M = Ta,Cu) octahedra (point-group symmetry -3m.) that are condensed into infinite chains along [001]. Adjacent chains are linked through the barium cations (site symmetry -6m2), which exhibit a coordination number of twelve. The M site is occupied by 2/3 of Ta^V and 1/3 of Cu^II, whereby the average M—S distances are slightly longer than those of ordered BaTaS₃. The classical charge balance of the title compound can be represented by [Ba²⁺] [(Ta/Cu)⁴⁺] [S²⁻]₃.

Keywords: crystal structure; quasi-one-dimensional structure; mixed-metal trisulfide.

CCDC reference: 1542709

1. Chemical context

Barium vanadium trisulfide, BaVS₃ (Takano et al., 1977 ), with which BaTaS₃ (Gardner et al., 1969 ) crystallizes isotypically in space group P6₃/mmc, has a chain structure. The observed conductivity was attributed to the formation of conduction bands via vanadium⋯vanadium d-orbital overlap. It shows three phase transitions and exhibits a number of intriguing physical properties (Nakamura et al., 1994 ). While both BaVS₃ and BaTaS₃ are composed of the same type of linear chains, BaTaS₃ shows metallic conductivity and a Curie–Weiss behaviour of the magnetic susceptibility (Gardner et al., 1969). To explore the physical properties of BaTaS₃ and related compounds, we have introduced copper and studied mixed-metal phases Ba(Ta/Cu)S₃. Here we report on the synthesis and structural characterization of the mixed-metal trisulfide with composition BaCu_1/3Ta_2/3S₃.

2. Structural commentary

BaCu_1/3Ta_2/3S₃ adopts the BaTaS₃ structure type in space group P6₃/mmc. A detailed description of this structure type has been given previously (Gardner et al., 1969). The asymmetric unit of BaCu_1/3Ta_2/3S₃ contains one Ba site (Wyckoff position 2c), one mixed-occupied (Cu/Ta) site (2a) and one S site (6h). The structure contains face-sharing octahedral [MS₆] (M = Cu, Ta) units, which construct infinite chains along [001] (Fig. 1). In the crystal structure, these chains are linked through Ba cations (coordination number 12) to adjacent chains (Fig. 2).

Figure 1
Face-sharing of MS₆ (M = Cu, Ta) octahedra in the structure of BaCu_1/3Ta_2/3S₃. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
The crystal structure of BaCu_1/3Ta_2/3S₃, viewed down [001].

The M site is occupationally disordered and contains 1/3 Cu and 2/3 Ta. It is surrounded by six S atoms with an M—S bond length of 2.475 (4) Å, which is slightly longer than that of ordered BaTaS₃ (2.461 Å; Gardner et al., 1969). This trend is in agreement with the different ionic radii of Ta (0.64 Å for Ta^V with coordination number of six) and Cu^II (0.73 Å) using the data provided by Shannon (1976 ).

The (Cu,Ta)⋯(Cu,Ta) distance within a chain is 2.9159 (3) Å, which is much shorter than the interchain (Cu,Ta)⋯(Cu,Ta) distance of 6.8437 (18) Å. The Ba—S interactions between adjacent metal sulfide chains are reflected by one shorter [3.422 (6) Å] and one longer distance [3.523 (3) Å], in good agreement with those found in other barium tantalum sulfides (Onoda & Saeki, 1989 ).

The classical charge balance of the title compound can be represented by the formula [Ba²⁺] [(Ta/Cu)⁴⁺] [S²⁻]₃.

3. Synthesis and crystallization

The title compound was prepared using solid-state reactions between the elements Cu, Ta, S and BaS. Ta powder (99.999%, Alfa Aesar Puratronic), Cu powder (99.999%, Alfa Aesar Puratronic), S powder (99.999%, Alfa Aesar Puratronic), and BaS powder (99.999%, Alfa Aesar Puratronic) were mixed in a fused-silica tube in an Ta:Cu:S:BaS molar ratio of 0.67:0.33:2:1. The tube was evacuated to 0.1 Pa, sealed and heated gradually (60 K h⁻¹) to 973 K, where it was kept for 2 d. The tube was then cooled to 673 K at a rate of 3 K h⁻¹ and then quenched to room temperature. The crystals are stable in air and alcohol.

Scanning electron microscopy (SEM) images of selected crystals were taken on a Hitachi S-4800 microscope equipped with an electron microprobe analyzer for a semiquantitative elemental analysis in the energy dispersive X-ray spectroscopy (EDX) mode. The presence of both copper and tantalum was confirmed (Fig. 3).

Figure 3
SEM image and EDX spectrum of BaCu_1/3Ta_2/3S₃.

4. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. The refinement of the model with occupational disorder on the M site resulted in a significant decrease of the reliability factors in comparison with a fully occupied Ta site (R1 = 0.73, wR = 0.197). No evidence, e.g. in the form of superstructure reflections, was found for an ordering of this site and thus a statistically disordered model was considered. In the final model, atoms of the disordered site were restrained to have the same displacement parameters, with a fixed Cu:Ta ratio of 1/3:2/3 required for charge neutrality and in good agreement with the EDX measurement. The remaining maximum and minimum electron densities are located 1.06 Å from the (Cu,Ta)1 site and 1.96 Å from the S1, respectively.

Table 1
Experimental details

Crystal data
Chemical formula	BaCu_1/3Ta_2/3S₃
M_r	375.14
Crystal system, space group	Hexagonal, P6₃/mmc
Temperature (K)	297
a, c (Å)	6.8350 (6), 5.8318 (5)
V (Å³)	235.94 (5)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	26.34
Crystal size (mm)	0.04 × 0.03 × 0.01

Data collection
Diffractometer	Bruker D8 QUEST
Absorption correction	Multi-scan (SADABS; Bruker, 2015 )
T_min, T_max	0.44, 0.86
No. of measured, independent and observed [I > 2σ(I)] reflections	4312, 125, 106
R_int	0.042
(sin θ/λ)_max (Å⁻¹)	0.645

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.113, 1.25
No. of reflections	125
No. of parameters	11
No. of restraints	2
Δρ_max, Δρ_min (e Å⁻³)	1.50, −1.50
Computer programs: APEX3 and SAINT (Bruker, 2015), SHELXT (Sheldrick, 2015a ), SHELXL2014/7 (Sheldrick, 2015b ), DIAMOND (Brandenburg, 2007 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1542709

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2056989017005266/wm5362sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989017005266/wm5362Isup3.hkl

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2015); cell refinement: SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 2007); software used to prepare material for publication: publCIF (Westrip, 2010).

Barium copper(II) tantalum(V) trisulfide top

Crystal data top

BaCu_0.33Ta_0.67S₃	D_x = 5.280 Mg m⁻³
M_r = 375.14	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6₃/mmc	Cell parameters from 1738 reflections
a = 6.8350 (6) Å	θ = 3.4–25.9°
c = 5.8318 (5) Å	µ = 26.34 mm⁻¹
V = 235.94 (5) Å³	T = 297 K
Z = 2	Plate, black
F(000) = 325	0.04 × 0.03 × 0.01 mm

Data collection top

Bruker D8 QUEST diffractometer	106 reflections with I > 2σ(I)
Detector resolution: 10.4167 pixels mm^-1	R_int = 0.042
phi and ω scans	θ_max = 27.3°, θ_min = 3.4°
Absorption correction: multi-scan (SADABS; Bruker, 2015)	h = −8→8
T_min = 0.44, T_max = 0.86	k = −8→8
4312 measured reflections	l = −7→6
125 independent reflections

Refinement top

Refinement on F²	11 parameters
Least-squares matrix: full	2 restraints
R[F² > 2σ(F²)] = 0.043	w = 1/[σ²(F_o²) + (0.0503P)² + 4.8137P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.113	(Δ/σ)_max < 0.001
S = 1.25	Δρ_max = 1.50 e Å⁻³
125 reflections	Δρ_min = −1.50 e Å⁻³

Special details top

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

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ba	0.6667	0.3333	0.75	0.0341 (7)
Ta	0	0	0.5	0.0707 (12)	0.6666 (8)
Cu	0	0	0.5	0.0707 (12)	0.3334 (18)
S	0.1689 (4)	0.3378 (8)	0.75	0.0449 (15)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ba	0.0246 (7)	0.0246 (7)	0.0529 (13)	0.0123 (4)	0	0
Ta	0.0306 (8)	0.0306 (8)	0.151 (3)	0.0153 (4)	0	0
Cu	0.0306 (8)	0.0306 (8)	0.151 (3)	0.0153 (4)	0	0
S	0.0217 (18)	0.015 (2)	0.096 (4)	0.0074 (10)	0	0

Geometric parameters (Å, º) top

Ba—Sⁱ	3.4176 (3)	Ta—S	2.475 (4)
Ba—Sⁱⁱ	3.4176 (3)	Ta—S^xiii	2.475 (4)
Ba—Sⁱⁱⁱ	3.4176 (3)	Ta—S^vii	2.475 (4)
Ba—S^iv	3.4176 (3)	Ta—S^xiv	2.475 (4)
Ba—S	3.4176 (3)	Ta—Ta^xv	2.9159 (3)
Ba—S^v	3.4176 (3)	Ta—Cu^xvi	2.9159 (3)
Ba—S^vi	3.506 (3)	Ta—Cu^xv	2.9159 (3)
Ba—S^vii	3.506 (3)	Ta—Ta^xvi	2.9159 (3)
Ba—S^viii	3.506 (3)	S—Cu^xv	2.475 (4)
Ba—S^ix	3.506 (3)	S—Ta^xv	2.475 (4)
Ba—S^x	3.506 (3)	S—Ba^xvii	3.4176 (3)
Ba—S^xi	3.506 (3)	S—Ba^vi	3.506 (3)
Ta—S^xii	2.475 (4)	S—Ba^ix	3.506 (3)
Ta—Sⁱⁱⁱ	2.475 (4)

Sⁱ—Ba—Sⁱⁱ	60.89 (16)	S^xii—Ta—Sⁱⁱⁱ	180.0
Sⁱ—Ba—Sⁱⁱⁱ	120.0010 (10)	S^xii—Ta—S	91.18 (10)
Sⁱⁱ—Ba—Sⁱⁱⁱ	59.11 (17)	Sⁱⁱⁱ—Ta—S	88.82 (10)
Sⁱ—Ba—S^iv	59.11 (17)	S^xii—Ta—S^xiii	88.82 (10)
Sⁱⁱ—Ba—S^iv	120.0010 (10)	Sⁱⁱⁱ—Ta—S^xiii	91.18 (10)
Sⁱⁱⁱ—Ba—S^iv	179.11 (16)	S—Ta—S^xiii	180.0
Sⁱ—Ba—S	179.11 (17)	S^xii—Ta—S^vii	88.82 (10)
Sⁱⁱ—Ba—S	120.0000 (10)	Sⁱⁱⁱ—Ta—S^vii	91.18 (10)
Sⁱⁱⁱ—Ba—S	60.89 (17)	S—Ta—S^vii	91.18 (10)
S^iv—Ba—S	119.9990 (10)	S^xiii—Ta—S^vii	88.82 (10)
Sⁱ—Ba—S^v	120.0000 (10)	S^xii—Ta—S^xiv	91.18 (10)
Sⁱⁱ—Ba—S^v	179.11 (17)	Sⁱⁱⁱ—Ta—S^xiv	88.82 (10)
Sⁱⁱⁱ—Ba—S^v	119.9990 (10)	S—Ta—S^xiv	88.82 (10)
S^iv—Ba—S^v	60.89 (17)	S^xiii—Ta—S^xiv	91.18 (10)
S—Ba—S^v	59.11 (17)	S^vii—Ta—S^xiv	180.0
Sⁱ—Ba—S^vi	89.75 (5)	S^xii—Ta—Ta^xv	126.10 (7)
Sⁱⁱ—Ba—S^vi	118.88 (3)	Sⁱⁱⁱ—Ta—Ta^xv	53.90 (7)
Sⁱⁱⁱ—Ba—S^vi	118.88 (3)	S—Ta—Ta^xv	53.90 (7)
S^iv—Ba—S^vi	61.40 (8)	S^xiii—Ta—Ta^xv	126.10 (7)
S—Ba—S^vi	89.75 (5)	S^vii—Ta—Ta^xv	126.10 (7)
S^v—Ba—S^vi	61.40 (8)	S^xiv—Ta—Ta^xv	53.90 (7)
Sⁱ—Ba—S^vii	118.88 (3)	S^xii—Ta—Cu^xvi	53.90 (7)
Sⁱⁱ—Ba—S^vii	89.75 (5)	Sⁱⁱⁱ—Ta—Cu^xvi	126.10 (7)
Sⁱⁱⁱ—Ba—S^vii	61.40 (8)	S—Ta—Cu^xvi	126.10 (7)
S^iv—Ba—S^vii	118.88 (3)	S^xiii—Ta—Cu^xvi	53.90 (7)
S—Ba—S^vii	61.40 (8)	S^vii—Ta—Cu^xvi	53.90 (7)
S^v—Ba—S^vii	89.75 (5)	S^xiv—Ta—Cu^xvi	126.10 (7)
S^vi—Ba—S^vii	147.76 (6)	Ta^xv—Ta—Cu^xvi	180.0
Sⁱ—Ba—S^viii	118.88 (3)	S^xii—Ta—Cu^xv	126.10 (7)
Sⁱⁱ—Ba—S^viii	89.75 (5)	Sⁱⁱⁱ—Ta—Cu^xv	53.90 (7)
Sⁱⁱⁱ—Ba—S^viii	61.40 (8)	S—Ta—Cu^xv	53.90 (7)
S^iv—Ba—S^viii	118.88 (3)	S^xiii—Ta—Cu^xv	126.10 (7)
S—Ba—S^viii	61.40 (8)	S^vii—Ta—Cu^xv	126.10 (7)
S^v—Ba—S^viii	89.75 (5)	S^xiv—Ta—Cu^xv	53.90 (7)
S^vi—Ba—S^viii	57.48 (11)	Ta^xv—Ta—Cu^xv	0
S^vii—Ba—S^viii	112.55 (14)	Cu^xvi—Ta—Cu^xv	180.0
Sⁱ—Ba—S^ix	89.75 (5)	S^xii—Ta—Ta^xvi	53.90 (7)
Sⁱⁱ—Ba—S^ix	118.88 (3)	Sⁱⁱⁱ—Ta—Ta^xvi	126.10 (7)
Sⁱⁱⁱ—Ba—S^ix	118.88 (3)	S—Ta—Ta^xvi	126.10 (7)
S^iv—Ba—S^ix	61.40 (8)	S^xiii—Ta—Ta^xvi	53.90 (7)
S—Ba—S^ix	89.75 (5)	S^vii—Ta—Ta^xvi	53.90 (7)
S^v—Ba—S^ix	61.40 (8)	S^xiv—Ta—Ta^xvi	126.10 (7)
S^vi—Ba—S^ix	112.55 (14)	Ta^xv—Ta—Ta^xvi	180.0
S^vii—Ba—S^ix	57.48 (11)	Cu^xvi—Ta—Ta^xvi	0
S^viii—Ba—S^ix	147.76 (6)	Cu^xv—Ta—Ta^xvi	180.0
Sⁱ—Ba—S^x	61.40 (8)	Ta—S—Cu^xv	72.2
Sⁱⁱ—Ba—S^x	61.40 (8)	Ta—S—Ta^xv	72.19 (13)
Sⁱⁱⁱ—Ba—S^x	89.75 (5)	Cu^xv—S—Ta^xv	0
S^iv—Ba—S^x	89.75 (5)	Ta—S—Ba	89.64 (7)
S—Ba—S^x	118.88 (3)	Cu^xv—S—Ba	89.64 (7)
S^v—Ba—S^x	118.88 (3)	Ta^xv—S—Ba	89.64 (7)
S^vi—Ba—S^x	57.48 (11)	Ta—S—Ba^xvii	89.64 (7)
S^vii—Ba—S^x	147.76 (6)	Cu^xv—S—Ba^xvii	89.64 (7)
S^viii—Ba—S^x	57.48 (11)	Ta^xv—S—Ba^xvii	89.64 (7)
S^ix—Ba—S^x	147.76 (6)	Ba—S—Ba^xvii	179.11 (16)
Sⁱ—Ba—S^xi	61.40 (8)	Ta—S—Ba^vi	159.82 (13)
Sⁱⁱ—Ba—S^xi	61.40 (8)	Cu^xv—S—Ba^vi	87.629 (7)
Sⁱⁱⁱ—Ba—S^xi	89.75 (5)	Ta^xv—S—Ba^vi	87.629 (7)
S^iv—Ba—S^xi	89.75 (5)	Ba—S—Ba^vi	90.25 (5)
S—Ba—S^xi	118.88 (3)	Ba^xvii—S—Ba^vi	90.25 (5)
S^v—Ba—S^xi	118.88 (3)	Ta—S—Ba^ix	87.629 (7)
S^vi—Ba—S^xi	147.76 (6)	Cu^xv—S—Ba^ix	159.82 (13)
S^vii—Ba—S^xi	57.48 (11)	Ta^xv—S—Ba^ix	159.82 (13)
S^viii—Ba—S^xi	147.76 (6)	Ba—S—Ba^ix	90.25 (5)
S^ix—Ba—S^xi	57.48 (11)	Ba^xvii—S—Ba^ix	90.25 (5)
S^x—Ba—S^xi	112.55 (13)	Ba^vi—S—Ba^ix	112.55 (13)

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

Funding information

Funding for this research was provided by: State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China. (award No. XDB04040200); CAS Center for Excellence in Superconducting Electronics, National key research and development program (award No. 2016YFB0901600); NSF of China (award Nos. 11404358, 51402341); Science and Technology Commission of Shanghai (award Nos. 13JC1405700, 14520722000).

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