research communications
0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2
and magnetic properties of LaCaaState Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China, and bDepartment of Physics, Shanghai University, Shanghai 200444, People's Republic of China
*Correspondence e-mail: huizhangmpg@hotmail.com, huangfq@mail.sic.ac.cn
The synthesis, structure, and magnetic properties of lithium dibarium calcium oxide fluoride disulfide are reported. LaCa0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2 crystallizes in the tetragonal P4/nmm. The structure exhibits disorder of the Ca2+ and Bi3+ cations, and the O2− and F− anions. The structure is composed of a stacking of [(O,F)2La2] layers and double [(Bi,Ca)S2] layers. Magnetic property measurements indicate a very small magnetization at 300 K and the existence of weak ferromagnetism at 2 K.
Keywords: crystal structure; magnetic properties; disorder.
CCDC reference: 1480636
1. Chemical context
Layered crystal structures seem to be a common stage on which to explore superconductivity (Vershinin et al., 2004; Kamihara et al., 2008; Chen et al., 2008; Fang et al., 2010). The discovery of [Fe2An2] (An = P, As, S, Se or Te) and [CuO2] superconducting layers has opened a new field in physics and chemistry for the exploration of low-dimensional superconductivity. Recently, superconductivity with transition temperatures of 4.5 K was reported in the BiS2-based compound Bi4O4S3 (Singh et al., 2012). Soon after, LnO1-xFxBiS2 (Ln = La, Ce, Pr and Nd), were reported to be superconducting with transition temperatures Tc of 3–10.6 K (Nagao et al., 2013; Demura et al., 2013). The mother BiS2-based layered compound AeFBiS2 (Ae = Ca, Sr or Ba; Lei et al., 2013; Han et al., 2008) is isostructural to LnOBiS2, with the [Ln2O2]2− layer being replaced by an isocharged [Sr2F2]2− block. The parent phase of SrFBiS2 shows semiconducting behavior, but electron-doped Sr0.5La0.5FBiS2 has a of 2.8 K (Lin et al., 2013). Herein the synthesis, structure and magnetic properties of LaCa0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2 are reported.
2. Structural commentary
We attempted to prepare the Ca and F double-doped compound La1−xCaxO1−2xF2xBiS2, but the results indicate the single-crystal composition is LaCa0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2. An SEM image shows thick plate-shaped crystals of LaCa0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2 (Fig. 1). LaO1−xFxBiS2 crystals usually show a thin-sheet shape (Fig. 2). From the EDXS analysis, we obtained the elemental components of La, Ca, Bi, S, F and O. The final composition was obtained by structure (details can be seen in the Refinement section).
The structure of LaCa0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2, shown in Fig. 3, is composed of a stacking of [(O,F)2La2] layers and double [(Bi,Ca)S2] layers as in LaO1−xFxBiS2. The double [(Bi,Ca)S2] layers show Bi1/Ca1—S2 distances of 2.8672 (6) Å representing equatorial bonds and Bi1/Ca1—S1 distances of 2.530 (3) Å representing axial bonds; these are a little shorter than the Bi1—S1 distance of 2.87476 (15) and Bi1—S2 distance of 2.530 (6) Å in LaO1−xFxBiS2. The [(O,F)2La2] layers exhibit O1/F1—La1 bond lengths of 2.4414 (6) Å and La1—O1/F1—La1 bond angles of 108.08 (2) and 112.29 (4)°, which are close to the La—O/F bond length of 2.4402 (8) Å and La1—O1/F1—La1 bond angles of 107.82 (3) and 112.82 (6)° in LaO1−xFxBiS2. The ionic radius of Ca2+ is 114 pm which is a little shorter than that of 117.2/117 pm for La3+/Bi3+. The distinct reduced Bi1/Ca1—S2 distances in the title compound reflect the fact that Ca substitutes Bi sites rather than La sites.
3. Magnetic property measurements
The magnetization versus temperature under a 1 T field for the title compound is given in Fig. 4. Magnetization versus magnetic field is given in Fig. 5 for fields ranging from −5 to 5 T at 2 K and 300 K. The magnetic properties indicate weak ferromagnetism at 2 K and a very low magnetization at 300 K. The is not observed in the measured temperature range. This might be related to the Ca substitution of the Bi site in the title compound. For superconducting LaO1−xFxBiS2 crystals, the at the is mainly directed by the Bi p orbital. [BiS2] layers play a vital role in the transport and superconducting properties. The Ca substitution of the Bi site leads to a hole doping which changed the electronic band structure and density of state of LaO1−xFxBiS2. Another reason might be the reduced F content in LaCa0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2 compared with LaO1−xFxBiS2.
4. Database survey
LnO1−xFxBiS2 (Ln = La, Ce, Pr and Nd) compounds were reported by Nagao et al. (2013) and Demura et al. (2013). AeFBiS2 (Ae = Ca, Sr, Ba) (Lei et al., 2013; Han et al., 2008) are isostructural to LnOBiS2. The doped Sr0.5La0.5FBiS2 (Lin et al., 2013) is isostructural to AeFBiS2.
5. Synthesis and crystallization
LaCa0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2 was prepared using of Bi2O3, CaF2, La2S3, Bi2S3 and Bi raw materials. The mixtures with a nominal composition of La0.85Ca0.15O0.70F0.30BiS2 were ground, pressed into pellets, sealed in an evacuated quartz tube, and heated at 1073 K for 3 d. High-quality single crystals were grown by using KI as the Nominal La0.85Ca0.15O0.70F0.30BiS2 and KI in the molar ratio of 1:3 were mixed and placed in a quartz tube, which was sealed and heated to 1273 K and kept at this temperature for 1 d, then cooled to room temperature in 10 d. The product was washed with distilled water and acetone, then dried at 353 K for 12 h; finally black plate-shaped crystals were obtained.
The morphology and element compositions were investigated by a scanning electronic microscope equipped with an energy dispersive
(EDXS, Oxford Instruments). The EDXS shows the atom % ratio for S:Ca:La:Bi to be 48.23: 6.94: 24.36: 20.48. O and F could not be determined precisely. Magnetic properties were measured on a multifunctional physical properties measurement system (PPMS, Quantum Design).6. Refinement
Crystal data, data collection and structure . The La, Bi, S and O atoms were located in difference maps and their positions were freely refined. Ca was assumed at La sites at first, but the show no reducing occupancy of La. The partial occupancy of Bi indicates a mixed occupancy with Ca. Ca and Bi were refined together later. EDXS measurements could not determine occupancies of O and F precisely. If the occupancies of F and O are refined together, the obtained composition is La2Bi1.859 (4)Ca0.141 (4)O0.48 (14)F0.52 (14)S4 with high standard errors for O and F. In order to keep charge neutrality, the occupancy of F was fixed to be the same as Ca so the final composition of LaCa0.143 (4)O0.857 (4)F0.143 (4)Bi0.857 (4)S2 was obtained.
details are summarized in Table 1Supporting information
CCDC reference: 1480636
https://doi.org/10.1107/S2056989016008082/pj2030sup1.cif
contains datablocks I, New_Global_Publ_Block. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989016008082/pj2030Isup2.hkl
Data collection: APEX2 (Bruker, 2004); cell
SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick 2015); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: publCIF (Westrip, 2010).Bi0.857Ca0.143F0.143LaO0.857S2 | Dx = 6.108 Mg m−3 |
Mr = 404.26 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, P4/nmm | Cell parameters from 189 reflections |
a = 4.0548 (9) Å | θ = 4.6–27.4° |
c = 13.370 (3) Å | µ = 44.78 mm−1 |
V = 219.82 (11) Å3 | T = 300 K |
Z = 2 | Block, blue |
F(000) = 342.3 | 0.05 × 0.05 × 0.02 mm |
Bruker D8 Quest diffractometer | Rint = 0.046 |
Radiation source: fine-focus sealed tube | θmax = 27.4°, θmin = 4.6° |
Profile fitted 2θ/ω scans (Clegg, 1981) | h = −5→5 |
Absorption correction: multi-scan (SADABS; Bruker, 2001) | k = −5→4 |
Tmin = 0.154, Tmax = 0.511 | l = −17→17 |
3493 measured reflections | 3 standard reflections every 90 reflections |
191 independent reflections | intensity decay: none |
190 reflections with I > 2σ(I) |
Refinement on F2 | Primary atom site location: difference Fourier map |
Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0318P)2 + 0.5025P] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.020 | (Δ/σ)max < 0.001 |
wR(F2) = 0.052 | Δρmax = 1.48 e Å−3 |
S = 1.31 | Δρmin = −1.53 e Å−3 |
191 reflections | Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
17 parameters | Extinction coefficient: 0.033 (3) |
0 restraints |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
La1 | 0.7500 | 0.7500 | 0.89827 (6) | 0.0127 (3) | |
Ca1 | 0.2500 | 0.2500 | 0.62178 (4) | 0.0126 (3) | 0.143 (4) |
Bi1 | 0.2500 | 0.2500 | 0.62178 (4) | 0.0126 (3) | 0.857 (4) |
F1 | 0.7500 | 0.2500 | 1.0000 | 0.0079 (14) | 0.143 (4) |
O1 | 0.7500 | 0.2500 | 1.0000 | 0.0079 (14) | 0.857 (4) |
S1 | 0.2500 | 0.2500 | 0.8110 (2) | 0.0104 (6) | |
S2 | 0.7500 | 0.7500 | 0.6221 (3) | 0.0236 (8) |
U11 | U22 | U33 | U12 | U13 | U23 | |
La1 | 0.0115 (4) | 0.0115 (4) | 0.0151 (5) | 0.000 | 0.000 | 0.000 |
Ca1 | 0.0146 (3) | 0.0146 (3) | 0.0087 (3) | 0.000 | 0.000 | 0.000 |
Bi1 | 0.0146 (3) | 0.0146 (3) | 0.0087 (3) | 0.000 | 0.000 | 0.000 |
F1 | 0.0087 (18) | 0.0087 (18) | 0.006 (3) | 0.000 | 0.000 | 0.000 |
O1 | 0.0087 (18) | 0.0087 (18) | 0.006 (3) | 0.000 | 0.000 | 0.000 |
S1 | 0.0101 (7) | 0.0101 (7) | 0.0109 (12) | 0.000 | 0.000 | 0.000 |
S2 | 0.0200 (10) | 0.0200 (10) | 0.0306 (18) | 0.000 | 0.000 | 0.000 |
La1—O1i | 2.4414 (6) | Ca1—Ca1v | 4.0548 (9) |
La1—O1ii | 2.4414 (6) | Ca1—Ca1viii | 4.0548 (9) |
La1—F1i | 2.4414 (6) | Ca1—Bi1ii | 4.0548 (9) |
La1—F1ii | 2.4414 (6) | Ca1—Bi1viii | 4.0548 (9) |
La1—F1 | 2.4414 (6) | F1—La1i | 2.4414 (6) |
La1—O1iii | 2.4414 (6) | F1—La1viii | 2.4414 (6) |
La1—O1 | 2.4414 (6) | F1—La1iii | 2.4414 (6) |
La1—F1iii | 2.4414 (6) | O1—La1i | 2.4414 (6) |
La1—S1 | 3.0954 (13) | O1—La1viii | 2.4414 (6) |
La1—S1iv | 3.0954 (13) | O1—La1iii | 2.4414 (6) |
La1—S1ii | 3.0954 (13) | S1—La1vi | 3.0954 (13) |
La1—S1v | 3.0954 (13) | S1—La1vii | 3.0954 (13) |
Ca1—S1 | 2.530 (3) | S1—La1viii | 3.0954 (13) |
Ca1—S2 | 2.8672 (6) | S2—Bi1iv | 2.8672 (6) |
Ca1—S2vi | 2.8672 (6) | S2—Ca1iv | 2.8672 (6) |
Ca1—S2vii | 2.8672 (6) | S2—Ca1v | 2.8672 (6) |
Ca1—S2viii | 2.8672 (6) | S2—Ca1ii | 2.8672 (6) |
Ca1—S2ix | 3.261 (4) | S2—Bi1ii | 2.8672 (6) |
Ca1—Ca1ii | 4.0548 (9) | S2—Bi1v | 2.8672 (6) |
Ca1—Ca1vii | 4.0548 (9) | S2—Ca1ix | 3.261 (4) |
O1i—La1—O1ii | 71.917 (18) | S2viii—Ca1—Ca1vii | 135.0 |
O1i—La1—F1i | 0.0 | S2ix—Ca1—Ca1vii | 90.0 |
O1ii—La1—F1i | 71.917 (18) | Ca1ii—Ca1—Ca1vii | 90.0 |
O1i—La1—F1ii | 71.917 (18) | S1—Ca1—Ca1v | 90.0 |
O1ii—La1—F1ii | 0.0 | S2—Ca1—Ca1v | 45.0 |
F1i—La1—F1ii | 71.917 (18) | S2vi—Ca1—Ca1v | 135.0 |
O1i—La1—F1 | 71.917 (18) | S2vii—Ca1—Ca1v | 135.0 |
O1ii—La1—F1 | 112.29 (4) | S2viii—Ca1—Ca1v | 45.0 |
F1i—La1—F1 | 71.917 (18) | S2ix—Ca1—Ca1v | 90.0 |
F1ii—La1—F1 | 112.29 (4) | Ca1ii—Ca1—Ca1v | 90.0 |
O1i—La1—O1iii | 112.29 (4) | Ca1vii—Ca1—Ca1v | 180.0 |
O1ii—La1—O1iii | 71.917 (18) | S1—Ca1—Ca1viii | 90.0 |
F1i—La1—O1iii | 112.29 (4) | S2—Ca1—Ca1viii | 135.0 |
F1ii—La1—O1iii | 71.917 (18) | S2vi—Ca1—Ca1viii | 45.0 |
F1—La1—O1iii | 71.917 (18) | S2vii—Ca1—Ca1viii | 135.0 |
O1i—La1—O1 | 71.917 (18) | S2viii—Ca1—Ca1viii | 45.0 |
O1ii—La1—O1 | 112.29 (4) | S2ix—Ca1—Ca1viii | 90.0 |
F1i—La1—O1 | 71.917 (18) | Ca1ii—Ca1—Ca1viii | 180.0 |
F1ii—La1—O1 | 112.29 (4) | Ca1vii—Ca1—Ca1viii | 90.0 |
F1—La1—O1 | 0.0 | Ca1v—Ca1—Ca1viii | 90.0 |
O1iii—La1—O1 | 71.917 (18) | S1—Ca1—Bi1ii | 90.0 |
O1i—La1—F1iii | 112.29 (4) | S2—Ca1—Bi1ii | 45.0 |
O1ii—La1—F1iii | 71.917 (18) | S2vi—Ca1—Bi1ii | 135.0 |
F1i—La1—F1iii | 112.29 (4) | S2vii—Ca1—Bi1ii | 45.0 |
F1ii—La1—F1iii | 71.917 (18) | S2viii—Ca1—Bi1ii | 135.0 |
F1—La1—F1iii | 71.917 (18) | S2ix—Ca1—Bi1ii | 90.0 |
O1iii—La1—F1iii | 0.0 | Ca1ii—Ca1—Bi1ii | 0.000 (15) |
O1—La1—F1iii | 71.917 (18) | Ca1vii—Ca1—Bi1ii | 90.0 |
O1i—La1—S1 | 138.93 (2) | Ca1v—Ca1—Bi1ii | 90.0 |
O1ii—La1—S1 | 138.93 (3) | Ca1viii—Ca1—Bi1ii | 180.0 |
F1i—La1—S1 | 138.93 (2) | S1—Ca1—Bi1viii | 90.0 |
F1ii—La1—S1 | 138.93 (3) | S2—Ca1—Bi1viii | 135.0 |
F1—La1—S1 | 70.49 (4) | S2vi—Ca1—Bi1viii | 45.0 |
O1iii—La1—S1 | 70.49 (4) | S2vii—Ca1—Bi1viii | 135.0 |
O1—La1—S1 | 70.49 (4) | S2viii—Ca1—Bi1viii | 45.0 |
F1iii—La1—S1 | 70.49 (4) | S2ix—Ca1—Bi1viii | 90.0 |
O1i—La1—S1iv | 70.49 (4) | Ca1ii—Ca1—Bi1viii | 180.0 |
O1ii—La1—S1iv | 70.49 (4) | Ca1vii—Ca1—Bi1viii | 90.0 |
F1i—La1—S1iv | 70.49 (4) | Ca1v—Ca1—Bi1viii | 90.0 |
F1ii—La1—S1iv | 70.49 (4) | Ca1viii—Ca1—Bi1viii | 0.000 (15) |
F1—La1—S1iv | 138.93 (3) | Bi1ii—Ca1—Bi1viii | 180.0 |
O1iii—La1—S1iv | 138.93 (2) | La1i—F1—La1viii | 108.082 (18) |
O1—La1—S1iv | 138.93 (3) | La1i—F1—La1iii | 112.29 (4) |
F1iii—La1—S1iv | 138.93 (2) | La1viii—F1—La1iii | 108.082 (18) |
S1—La1—S1iv | 135.72 (11) | La1i—F1—La1 | 108.082 (18) |
O1i—La1—S1ii | 138.93 (3) | La1viii—F1—La1 | 112.29 (4) |
O1ii—La1—S1ii | 70.49 (4) | La1iii—F1—La1 | 108.082 (18) |
F1i—La1—S1ii | 138.93 (3) | La1i—O1—La1viii | 108.082 (18) |
F1ii—La1—S1ii | 70.49 (4) | La1i—O1—La1iii | 112.29 (4) |
F1—La1—S1ii | 138.93 (3) | La1viii—O1—La1iii | 108.082 (18) |
O1iii—La1—S1ii | 70.49 (4) | La1i—O1—La1 | 108.082 (18) |
O1—La1—S1ii | 138.93 (3) | La1viii—O1—La1 | 112.29 (4) |
F1iii—La1—S1ii | 70.49 (4) | La1iii—O1—La1 | 108.082 (18) |
S1—La1—S1ii | 81.84 (4) | Ca1—S1—La1 | 112.14 (5) |
S1iv—La1—S1ii | 81.84 (4) | Ca1—S1—La1vi | 112.14 (5) |
O1i—La1—S1v | 70.49 (4) | La1—S1—La1vi | 135.72 (11) |
O1ii—La1—S1v | 138.93 (3) | Ca1—S1—La1vii | 112.14 (5) |
F1i—La1—S1v | 70.49 (4) | La1—S1—La1vii | 81.84 (4) |
F1ii—La1—S1v | 138.93 (3) | La1vi—S1—La1vii | 81.84 (4) |
F1—La1—S1v | 70.49 (4) | Ca1—S1—La1viii | 112.14 (5) |
O1iii—La1—S1v | 138.93 (3) | La1—S1—La1viii | 81.84 (4) |
O1—La1—S1v | 70.49 (4) | La1vi—S1—La1viii | 81.84 (4) |
F1iii—La1—S1v | 138.93 (3) | La1vii—S1—La1viii | 135.72 (11) |
S1—La1—S1v | 81.84 (4) | Ca1—S2—Bi1iv | 179.8 |
S1iv—La1—S1v | 81.84 (4) | Ca1—S2—Ca1iv | 179.82 (17) |
S1ii—La1—S1v | 135.72 (11) | Bi1iv—S2—Ca1iv | 0.0 |
S1—Ca1—S2 | 89.91 (9) | Ca1—S2—Ca1v | 90.0 |
S1—Ca1—S2vi | 89.91 (9) | Bi1iv—S2—Ca1v | 90.0 |
S2—Ca1—S2vi | 179.82 (17) | Ca1iv—S2—Ca1v | 90.0 |
S1—Ca1—S2vii | 89.91 (9) | Ca1—S2—Ca1ii | 90.0 |
S2—Ca1—S2vii | 90.000 (1) | Bi1iv—S2—Ca1ii | 90.0 |
S2vi—Ca1—S2vii | 90.000 (1) | Ca1iv—S2—Ca1ii | 90.0 |
S1—Ca1—S2viii | 89.91 (9) | Ca1v—S2—Ca1ii | 179.82 (17) |
S2—Ca1—S2viii | 90.000 (1) | Ca1—S2—Bi1ii | 90.0 |
S2vi—Ca1—S2viii | 90.0 | Bi1iv—S2—Bi1ii | 90.0 |
S2vii—Ca1—S2viii | 179.82 (17) | Ca1iv—S2—Bi1ii | 90.0 |
S1—Ca1—S2ix | 180.0 | Ca1v—S2—Bi1ii | 179.82 (17) |
S2—Ca1—S2ix | 90.09 (9) | Ca1ii—S2—Bi1ii | 0.00 (2) |
S2vi—Ca1—S2ix | 90.09 (9) | Ca1—S2—Bi1v | 90.0 |
S2vii—Ca1—S2ix | 90.09 (9) | Bi1iv—S2—Bi1v | 90.0 |
S2viii—Ca1—S2ix | 90.09 (9) | Ca1iv—S2—Bi1v | 90.0 |
S1—Ca1—Ca1ii | 90.0 | Ca1v—S2—Bi1v | 0.00 (2) |
S2—Ca1—Ca1ii | 45.0 | Ca1ii—S2—Bi1v | 179.82 (17) |
S2vi—Ca1—Ca1ii | 135.0 | Bi1ii—S2—Bi1v | 179.82 (17) |
S2vii—Ca1—Ca1ii | 45.0 | Ca1—S2—Ca1ix | 89.91 (9) |
S2viii—Ca1—Ca1ii | 135.0 | Bi1iv—S2—Ca1ix | 89.9 |
S2ix—Ca1—Ca1ii | 90.0 | Ca1iv—S2—Ca1ix | 89.91 (9) |
S1—Ca1—Ca1vii | 90.0 | Ca1v—S2—Ca1ix | 89.91 (9) |
S2—Ca1—Ca1vii | 135.0 | Ca1ii—S2—Ca1ix | 89.91 (9) |
S2vi—Ca1—Ca1vii | 45.0 | Bi1ii—S2—Ca1ix | 89.9 |
S2vii—Ca1—Ca1vii | 45.0 | Bi1v—S2—Ca1ix | 89.9 |
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) x, y+1, z; (iii) −x+1, −y+1, −z+2; (iv) x+1, y+1, z; (v) x+1, y, z; (vi) x−1, y−1, z; (vii) x−1, y, z; (viii) x, y−1, z; (ix) −x+1, −y+1, −z+1. |
Acknowledgements
This work was supported financially by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (grant No. XDB04040200).
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