Redetermination of NaGdS₂, NaLuS₂ and NaYS₂

The title structures NaGdS₂ (sodium gadolinium sulfide), NaLuS₂ (sodium lutetium sulfide) and NaYS₂ (sodium yttrium sulfide) were redetermined in order to improve the structural information available for the family of group 1 and thallium rare earth sulfides, which are isostructural with the rhombohedral α-NaFeO₂ structure type. In particular, the present investigation has been directed at the rhombohedral sodium rare earth sulfides. The observed dependence of the fractional coordinate z(S²⁻) on the identity of the rare earth element in the newly determined structures is in agreement with the known structures of the potassium and rubidium analogues. Crystals of NaGdS₂ and NaLuS₂ display obverse–reverse twinning.

S1. Introduction

This study was motivated by the potential use of the rhombohedral group 1 rare earth sulfides as X-ray and white LED luminophores (Verheijen et al., 1975). Optical properties were reported recently for several group 1 lanthanide ternary sulfides M⁺Ln³⁺S₂, namely RbLaS₂ doped with Ce, Pr, Sm, Eu and Tb (Havlák et al., 2011); RbLuS₂ doped with Ce, Pr, Sm and Tb (Jarý et al., 2012); RbGdS₂ doped with Ce and Pr (Jarý et al., 2013a); KLuS₂ doped with Eu (Jarý et al., 2013b); KLnS₂ doped with Pr, Sm, Tb and Tm (Ln = La, Gd, Lu) (Jarý, Havlák, Bárta, Mihóková & Nikl, 2014); and KLuS₂ doped with Ce (Jarý, Havlák, Bárta, Mihóková, Pruša & Nikl, 2014). (The lanthanide elements are hereinafter denoted by Ln.)

S2. Experimental

S2.1. Synthesis and crystallization

The starting raw materials were Na₂S (99.9%, Alfa Aesar), Gd₂O₃ (99.999%, Koch–Light Laboratories), Lu₂O₃ (99.999%, Fluka), Y₂O₃ (99.999%, Fluka) and CeO₂ (99.95%, Koch–Light Laboratories). The gases used were Ar (99.999%, Linde) and H₂S (99.5%, Linde). The chemical reactions were carried out in a monocrystalline sapphire tube (99.99% Al₂O₃, Crytur). The tube was placed in an electric resistance furnace equipped with heating/cooling rate regulation. The scheme of the set-up was outlined by Havlák et al. (2011). Either Ar or H₂S gas was then connected to the reaction tube. The gases were taken directly from pressurized bottles using a three-way stopcock to switch between them. A mixture of Na₂S and one of the rare earth (RE) oxides in the molar ratio 40:1 was the starting material for the Ce³⁺-doped compounds. (The rare earth oxides were doped with 0.05 mol% cerium in conjunction with the investigation of the title compounds as scintillation materials.) Ce doping was done by simple mixing and grinding of RE₂O₃ (RE = Gd, Lu and Y) and CeO₂. Prior to the reaction itself, the reagents (Na₂S and RE₂O₃:CeO₂) were mixed and the mixture homogenized in an agate mortar. The mixture was placed in a corundum boat (99.7% Al₂O₃; Dengfeng Jinyu Thermoelectric Material Co.) and placed in a sapphire tube (inner volume 0.9 l). The mixture was then heated to 1323 K for NaLuS₂ and NaYS₂, and to 1373 K for NaGdS₂, using the electric resistance furnace (heating rate 10 K min^-1) under a flow of argon gas from a pressurized bottle (15 l h^-1). After the desired temperature had been reached, the reaction mixture was annealed for 2 h under a flow of hydrogen sulfide (5 l h^-1). Following annealing, the system was cooled under a flow of Ar (1 K min^-1, 0.3 l h^-1). Upon reaching room temperature, the corundum boat was removed from the tube furnace and the reaction products were purified by suspension and decantation – three times with distilled water and once with ethanol. Na₂S was removed with water while the sodium rare earth sulfides were left behind. The yield was nearly 100%, with any loss attributed to imperfect product separation. The products were stored in small glass flasks under an Ar atmosphere and used for further analysis. Ternary sulfide NaRES₂ is produced according to the following reaction scheme:

Na₂S(l) + RE₂O₃(s) + 3 H₂S(g) → 2NaRES₂(s) + 3H₂O(g).

As the melting point of sodium sulfide (Alfa Aesar) is lower than 1323 K, the reaction occurred in the melt.

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. The structures were solved using SUPERFLIP (Palatinus & Chapuis, 2007) implemented in JANA2006 (Petříček et al., 2006). All of the samples were doped with 0.05 mol% of Ce, which was neglected during refinement. The crystals of NaGdS₂ and NaLuS₂ (at least those used for diffraction measurements) suffered obverse–reverse twinning, with domain fractions equal to 0.9243 (8):0.0757 (8) and 0.808 (2):0.192 (2), respectively. The twinning matrix relation was h₂ = h₁ + k₁; k₂ = -h₁; l₂ = l₁. The R_int value was quite high (0.1092) in the case of NaYS₂, which is probably a result of unusually high background.

S3. Results and discussion

We recently reported the structures of KLaS₂, KPrS₂, KEuS₂, KGdS₂, KLuS₂, KYS₂, RbYS₂ and NaLaS₂ (Fábry et al., 2014). With the exception of NaLaS₂, all of these structures belong to the rhombohedral modification and are isostructural with the title compounds. The structure of NaLaS₂ is cubic and is derived from the NaCl structure type, with Na⁺ and La³⁺ disordered at the cation position. Since crystals of NaLaS₂ produce intense diffuse scattering, it is likely that the structure is more complicated than the simple model with a statistical distribution of Na⁺ and La³⁺ at the cation positions of the ideal NaCl structure (Fábry et al., 2014). Further work on this problem is in progress.

In contrast, the rhombohedral modification is characterized by the occurrence of either group 1 or thallium(1+) and rare earth cations at different sites in the structure. Fig. 1 shows a representative of this structural family, the title structure of NaGdS₂. Both the cationic species and S^2- anions are ordered in planes perpendicular to the c axis. Each S^2- anion is surrounded by 3+3 cations in a trigonal anti­prismatic environment. The driving force for the segregation of the cationic species onto distinct ordered sites is the different size of the cations and the related bonding properties (Fábry et al., 2014).

Previous structure analyses of the sodium rare earth sulfides seem to present inconsistencies, as seen in Fig. 2, which presents z(S^2-), i.e. the fractional coordinates of S^2-, in group 1 and thallium rare earth sulfides. (The numerical data presented in Fig. 2 are collected in a table in the Supporting information.) As seen in Fig. 2, the fractional coordinates z(S^2-) are improbably scattered for the rhombohedral sodium rare earth sulfides in contrast with what is seen for the rare earth sulfides of other alkali metals. The title structures were redetermined in order to improve the data for this series of compounds.

The present determinations are in agreement (Fig. 2) with the trends seen for KGdS₂, KLuS₂ and KYS₂ (Fábry et al., 2014), and for RbGdS₂ (Bronger et al., 1996), RbLuS₂ (Bronger et al., 1996) and RbYS₂ (Fábry et al., 2014).

However, there is a significant discrepancy between the determination of NaGdS₂ by Sato et al. (1984) with z(S^2-) = 0.241 and the present structure determination, with z(S^2-) = 0.2433 (1).

The structure of NaYS₂ was not determined reliably in a previous study, because the fractional coordinate z(S^2-) was derived from the ionic radii as 0.24 (Brüesch & Schüler, 1971).

As for NaLuS₂, two quite different structure determinations were reported by Tromme (1971) [z(S^2-) = 0.231] and by Schleid & Lissner (1993) [z(S^2-) = 0.24284 (9)]. The determination by Tromme (1971) is an evident outlier and therefore it has not been included in Fig. 2.

Fig. 2 also shows that potassium rare earth sulfides seem to have been dubiously determined in the inter­val from KDyS₂ to KYbS₂. KSmS₂ also seems to have been dubiously determined.

In conclusion, the present work provides useful extra data on this series of compounds and highlights shortcomings in historic data sets. [Added text OK? If not, please supply an alternative conclusion to tie the paper together.]

Related literature

For overall information about group 1 rare earth sulfides, see Fábry et al. (2014). For selected Li rare earth sulfides, see Ohtani et al. (1987). For selected Na rare earth sulfides, see Sato et al. (1984), Ballestracci & Bertaut (1964) and Schleid & Lissner (1993), and specifically for NaYS₂, see Brüesch & Schüler (1971). For selected K rare earth sulfides, see Fábry et al. (2014), Plug & Verschoor (1976), Verheijen et al. (1975) and Ballestracci (1965). For selected Rb rare earth sulfides, see Bronger et al. (1996) and Fábry et al. (2014). For selected Cs rare earth sulfides, see Bronger et al. (1993). For selected Tl rare earth sulfides, see Tromme (1971) and Duczmal & Pawlak (1994). For information about the preparation and application of the structural family of rhombohedral group 1 rare earth sulfides as white LED luminophors, see Verheijen et al. (1975) and Havlák et al. (2011); Jarý et al. (2012, 2013a, 2013b; Jarý, Havlák, Bárta, Mihóková & Nikl, 2014; Jarý, Havlák, Bárta, Mihóková, Pruša & Nikl, 2014).

Computing details

For all compounds, data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis PRO (Agilent, 2012); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: JANA2006 (Petříček et al., 2006).

Figures

Fig. 1. A view of the unit cell of NaGdS₂, one of the isostructural title structures. The layer of atoms at z = 0 is composed of Na⁺ which are depicted as white spheres; the following layer is composed of S^2- (yellow spheres) and the blue spheres in the subsequent layer represent Gd³⁺.

Fig. 2. Fractional coordinate z(S^2-) in the group 1 and thallium rare earth sulfides. The figure is based on data compiled in a table in the Supporting information (Ln denotes a lathanide). All LiLnS₂ (Ohtani et al., 1987); NaGdS₂ (Sato et al., 1984); NaHoS₂ and NaErS₂ (Ballestracci & Bertaut, 1964); NaTmS₂ (Schleid & Lissner, 1993); NaYbS₂ and NaYS₂ (this study); KLaS₂ (Fábry et al., 2014); KCeS₂ (Plug & Verschoor, 1976); KPrS₂ (Fábry et al., 2014); KNdS₂ (Verheijen et al., 1975); KSmS₂ (Ballestracci, 1965); KEuS₂ and KGdS₂ (Fábry et al., 2014); KDyS₂, KHoS₂, KErS₂ and KYbS₂ (Ballestracci, 1965); KLuS₂ and KYS₂ (Fábry et al., 2014); all RbLnS₂ (Bronger et al., 1996); RbYS₂ (Fábry et al., 2014); all CsLnS₂ (Bronger et al., 1993); all TlLnS₂ (Duczmal & Pawlak, 1994).

(I) Sodium gadolinium sulfide

Crystal data

NaGdS2	Dx = 4.388 Mg m^−3
Mr = 244.4	Mo Kα radiation, λ = 0.7107 Å
Trigonal, R3m	Cell parameters from 685 reflections
Hall symbol: -R 3 2"	θ = 5.9–27.0°
a = 4.0138 (4) Å	µ = 18.91 mm^−1
c = 19.878 (2) Å	T = 304 K
V = 277.34 (5) Å^3	Plate, pink
Z = 3	0.12 × 0.09 × 0.03 mm
F(000) = 321

Data collection

Agilent Xcalibur Gemini ultra diffractometer	164 independent reflections
Radiation source: X-ray tube	161 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.031
Detector resolution: 5.1892 pixels mm^-1	θmax = 27.8°, θmin = 3.1°
ω scans	h = −5→4
Absorption correction: analytical [CrysAlis PRO (Agilent, 2012); analytical numeric absorption correction using a multifaceted crystal (Clark & Reid, 1995)]	k = −4→4
Tmin = 0.213, Tmax = 0.561	l = −18→25
935 measured reflections

Refinement

Refinement on F^2	0 constraints
R[F^2 > 2σ(F^2)] = 0.020	Weighting scheme based on measured s.u.'s w = 1/[σ^2(I) + 0.0004I^2]
wR(F^2) = 0.048	(Δ/σ)max = 0.015
S = 1.35	Δρmax = 0.73 e Å^−3
164 reflections	Δρmin = −0.54 e Å^−3
10 parameters	Extinction correction: B-C type 1 Lorentzian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 140 (20)

Special details

Refinement. The refinement has been carried out under assumption of presence of obverse–reverse twinning with the refined domain-state proportions 0.9243 (8)/0.0757 (8).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Na1	0	0	0	0.0182 (16)
Gd1	0.333333	0.666667	0.166667	0.0088 (3)
S1	0	0	0.24332 (12)	0.0100 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Na1	0.0183 (19)	0.0183 (19)	0.018 (3)	0.0092 (10)	0	0
Gd1	0.0074 (4)	0.0074 (4)	0.0116 (5)	0.00369 (18)	0	0
S1	0.0089 (7)	0.0089 (7)	0.0121 (12)	0.0045 (4)	0	0

Geometric parameters (Å, º)

Gd1—S1	2.7734 (14)	Na1—S1^iv	2.9278 (15)
Gd1—S1^i	2.7734 (13)	S1—S1^x	4.0138 (12)
Gd1—S1^ii	2.7734 (14)	S1—S1^xi	4.0138 (8)
Gd1—S1^iii	2.7734 (14)	S1—S1^xii	4.0138 (8)
Gd1—S1^iv	2.7734 (13)	S1—S1^i	4.0138 (8)
Gd1—S1^v	2.7734 (14)	S1—S1^xiii	4.0138 (8)
Na1—S1^vi	2.9278 (15)	S1—S1^ii	4.0138 (12)
Na1—S1^vii	2.9278 (15)	S1—S1^ix	3.828 (3)
Na1—S1^viii	2.9278 (15)	S1—S1^iii	3.828 (3)
Na1—S1^ix	2.9278 (15)	S1—S1^iv	3.828 (3)
Na1—S1^iii	2.9278 (15)
S1^vi—Na1—S1^vii	86.54 (4)	Na1^xv—S1—Na1^xvi	86.54 (5)
S1^vi—Na1—S1^viii	86.54 (4)	S1—Gd1—S1^i	92.71 (4)
S1^vi—Na1—S1^ix	93.46 (4)	S1—Gd1—S1^ii	92.71 (4)
S1^vi—Na1—S1^iii	93.46 (4)	S1—Gd1—S1^iii	87.29 (4)
S1^vi—Na1—S1^iv	180.0 (5)	S1—Gd1—S1^iv	87.29 (4)
S1^vii—Na1—S1^viii	86.54 (4)	S1—Gd1—S1^v	180.0 (5)
S1^vii—Na1—S1^ix	93.46 (4)	S1^i—Gd1—S1^ii	92.71 (4)
S1^vii—Na1—S1^iii	180.0 (5)	S1^i—Gd1—S1^iii	87.29 (4)
S1^vii—Na1—S1^iv	93.46 (4)	S1^i—Gd1—S1^iv	180.0 (5)
S1^viii—Na1—S1^ix	180.0 (5)	S1^i—Gd1—S1^v	87.29 (4)
S1^viii—Na1—S1^iii	93.46 (4)	S1^ii—Gd1—S1^iii	180.0 (5)
S1^viii—Na1—S1^iv	93.46 (4)	S1^ii—Gd1—S1^iv	87.29 (4)
S1^ix—Na1—S1^iii	86.54 (4)	S1^ii—Gd1—S1^v	87.29 (4)
S1^ix—Na1—S1^iv	86.54 (4)	S1^iii—Gd1—S1^iv	92.71 (4)
S1^iii—Na1—S1^iv	86.54 (4)	S1^iii—Gd1—S1^v	92.71 (4)
Na1^xiv—S1—Na1^xv	86.54 (5)	S1^iv—Gd1—S1^v	92.71 (4)
Na1^xiv—S1—Na1^xvi	86.54 (5)

Symmetry codes: (i) x, y+1, z; (ii) x+1, y+1, z; (iii) y−1/3, x+1/3, −z+1/3; (iv) y+2/3, x+1/3, −z+1/3; (v) y+2/3, x+4/3, −z+1/3; (vi) x−2/3, y−1/3, z−1/3; (vii) x+1/3, y−1/3, z−1/3; (viii) x+1/3, y+2/3, z−1/3; (ix) y−1/3, x−2/3, −z+1/3; (x) x−1, y−1, z; (xi) x−1, y, z; (xii) x, y−1, z; (xiii) x+1, y, z; (xiv) x−1/3, y−2/3, z+1/3; (xv) x−1/3, y+1/3, z+1/3; (xvi) x+2/3, y+1/3, z+1/3.

(II) Sodium lutetium sulfide

Crystal data

NaLuS2	Dx = 5.015 Mg m^−3
Mr = 262.1	Mo Kα radiation, λ = 0.7107 Å
Trigonal, R3m	Cell parameters from 673 reflections
Hall symbol: -R 3 2"	θ = 6.1–28.8°
a = 3.8909 (4) Å	µ = 29.49 mm^−1
c = 19.850 (3) Å	T = 300 K
V = 260.24 (6) Å^3	Plate, pink
Z = 3	0.12 × 0.11 × 0.04 mm
F(000) = 342

Data collection

Agilent Xcalibur Gemini ultra diffractometer	183 independent reflections
Radiation source: Enhance (Mo) X-ray source	183 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.053
Detector resolution: 5.1892 pixels mm^-1	θmax = 29.4°, θmin = 3.1°
ω scans	h = −5→4
Absorption correction: analytical [CrysAlis PRO (Agilent, 2012); analytical numeric absorption correction using a multifaceted crystal (Clark & Reid, 1995)]	k = −4→5
Tmin = 0.150, Tmax = 0.508	l = −26→24
947 measured reflections

Refinement

Refinement on F^2	0 constraints
R[F^2 > 2σ(F^2)] = 0.031	Weighting scheme based on measured s.u.'s w = 1/[σ^2(I) + 0.0004I^2]
wR(F^2) = 0.066	(Δ/σ)max = 0.011
S = 1.83	Δρmax = 2.05 e Å^−3
183 reflections	Δρmin = −1.83 e Å^−3
10 parameters	Extinction correction: B-C type 1 Lorentzian isotropic (Becker & Coppens, 1974)
0 restraints	Extinction coefficient: 90 (20)

Special details

Refinement. The refinement has been carried out under assumption of presence of obverse–reverse twinning with the refined domain-state proportions 0.808 (2)/0.192 (2).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Lu1	0.333333	0.666667	0.166667	0.0090 (3)
Na1	0	0	0	0.017 (2)
S1	0	1	0.24146 (17)	0.0091 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Lu1	0.0061 (4)	0.0061 (4)	0.0148 (6)	0.0030 (2)	0	0
Na1	0.014 (3)	0.014 (3)	0.021 (5)	0.0072 (13)	0	0
S1	0.0078 (10)	0.0078 (10)	0.0117 (17)	0.0039 (5)	0	0

Geometric parameters (Å, º)

Lu1—S1^i	2.693 (2)	Na1—S1^iv	2.893 (2)
Lu1—S1	2.6927 (19)	S1—S1^x	3.8909 (12)
Lu1—S1^ii	2.693 (2)	S1—S1^xi	3.8909 (8)
Lu1—S1^iii	2.693 (2)	S1—S1^i	3.8909 (8)
Lu1—S1^iv	2.6927 (19)	S1—S1^xii	3.8909 (8)
Lu1—S1^v	2.693 (2)	S1—S1^ii	3.8909 (8)
Na1—S1^vi	2.893 (2)	S1—S1^xiii	3.8909 (12)
Na1—S1^vii	2.893 (2)	S1—S1^iii	3.723 (4)
Na1—S1^viii	2.893 (2)	S1—S1^xiv	3.723 (4)
Na1—S1^ix	2.893 (2)	S1—S1^v	3.723 (4)
Na1—S1^iii	2.893 (2)
S1^i—Lu1—S1	92.52 (6)	Lu1^xi—S1—S1^x	43.74 (4)
S1^i—Lu1—S1^ii	92.52 (6)	Lu1^xi—S1—S1^xi	43.74 (4)
S1^i—Lu1—S1^iii	87.48 (6)	Lu1^xi—S1—S1^i	90.00 (4)
S1^i—Lu1—S1^iv	87.48 (6)	Lu1^xi—S1—S1^xii	90.00 (4)
S1^i—Lu1—S1^v	180.0 (5)	Lu1^xi—S1—S1^ii	136.26 (9)
S1—Lu1—S1^ii	92.52 (6)	Lu1^xi—S1—S1^xiii	136.26 (9)
S1—Lu1—S1^iii	87.48 (6)	Lu1^xi—S1—S1^iii	46.26 (4)
S1—Lu1—S1^iv	180.0 (5)	Lu1^xi—S1—S1^xiv	46.26 (4)
S1—Lu1—S1^v	87.48 (6)	Lu1^xi—S1—S1^v	93.65 (10)
S1^ii—Lu1—S1^iii	180.0 (5)	Lu1—S1—Lu1^xii	92.52 (9)
S1^ii—Lu1—S1^iv	87.48 (6)	Lu1—S1—Na1^xv	91.356 (12)
S1^ii—Lu1—S1^v	87.48 (6)	Lu1—S1—Na1^xvi	174.39 (11)
S1^iii—Lu1—S1^iv	92.52 (6)	Lu1—S1—Na1^xvii	91.356 (12)
S1^iii—Lu1—S1^v	92.52 (6)	Lu1^xii—S1—Na1^xv	174.39 (11)
S1^iv—Lu1—S1^v	92.52 (6)	Lu1^xii—S1—Na1^xvi	91.356 (12)
Lu1^xi—S1—Lu1	92.52 (9)	Lu1^xii—S1—Na1^xvii	91.356 (13)
Lu1^xi—S1—Lu1^xii	92.52 (9)	Na1^xv—S1—Na1^xvi	84.50 (8)
Lu1^xi—S1—Na1^xv	91.356 (13)	Na1^xv—S1—Na1^xvii	84.50 (8)
Lu1^xi—S1—Na1^xvi	91.356 (12)	Na1^xvi—S1—Na1^xvii	84.50 (8)
Lu1^xi—S1—Na1^xvii	174.39 (11)

Symmetry codes: (i) x, y−1, z; (ii) x+1, y, z; (iii) y−4/3, x+1/3, −z+1/3; (iv) y−1/3, x+1/3, −z+1/3; (v) y−1/3, x+4/3, −z+1/3; (vi) x−2/3, y−4/3, z−1/3; (vii) x+1/3, y−4/3, z−1/3; (viii) x+1/3, y−1/3, z−1/3; (ix) y−4/3, x−2/3, −z+1/3; (x) x−1, y−1, z; (xi) x−1, y, z; (xii) x, y+1, z; (xiii) x+1, y+1, z; (xiv) y−4/3, x+4/3, −z+1/3; (xv) x−1/3, y+1/3, z+1/3; (xvi) x−1/3, y+4/3, z+1/3; (xvii) x+2/3, y+4/3, z+1/3.

(III) Sodium yttrium sulfide

Crystal data

NaYS2	Dx = 3.248 Mg m^−3
Mr = 176	Mo Kα radiation, λ = 0.7107 Å
Trigonal, R3m	Cell parameters from 688 reflections
Hall symbol: -R 3 2"	θ = 6.0–28.5°
a = 3.9604 (12) Å	µ = 17.21 mm^−1
c = 19.867 (8) Å	T = 302 K
V = 269.9 (2) Å^3	Prism, colourless
Z = 3	0.12 × 0.07 × 0.06 mm
F(000) = 246

Data collection

Agilent Xcalibur Gemini ultra diffractometer	120 independent reflections
Radiation source: Enhance (Mo) X-ray source	112 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.109
Detector resolution: 5.1892 pixels mm^-1	θmax = 29.5°, θmin = 3.1°
ω scans	h = −5→5
Absorption correction: analytical [CrysAlis PRO (Agilent, 2012); analytical numeric absorption correction using a multifaceted crystal (Clark & Reid, 1995)]	k = −5→5
Tmin = 0.344, Tmax = 0.479	l = −25→25
1233 measured reflections

Refinement

Refinement on F^2	0 restraints
R[F^2 > 2σ(F^2)] = 0.031	0 constraints
wR(F^2) = 0.067	Weighting scheme based on measured s.u.'s w = 1/[σ^2(I) + 0.0004I^2]
S = 1.78	(Δ/σ)max = 0.002
120 reflections	Δρmax = 0.93 e Å^−3
8 parameters	Δρmin = −0.72 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Y1	0.333333	0.666667	0.166667	0.0124 (4)
Na1	0	0	0	0.0207 (14)
S1	0	0	0.24260 (10)	0.0125 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Y1	0.0088 (4)	0.0088 (4)	0.0196 (7)	0.0044 (2)	0	0
Na1	0.0181 (16)	0.0181 (16)	0.026 (3)	0.0090 (8)	0	0
S1	0.0095 (7)	0.0095 (7)	0.0183 (11)	0.0048 (3)	0	0

Geometric parameters (Å, º)

Y1—S1	2.739 (2)	Na1—S1^iv	2.912 (2)
Y1—S1^i	2.7393 (14)	S1—S1^x	3.960 (4)
Y1—S1^ii	2.739 (2)	S1—S1^xi	3.960 (2)
Y1—S1^iii	2.739 (2)	S1—S1^xii	3.960 (2)
Y1—S1^iv	2.7393 (14)	S1—S1^i	3.960 (2)
Y1—S1^v	2.739 (2)	S1—S1^xiii	3.960 (2)
Na1—S1^vi	2.912 (2)	S1—S1^ii	3.960 (4)
Na1—S1^vii	2.9117 (16)	S1—S1^ix	3.786 (3)
Na1—S1^viii	2.912 (2)	S1—S1^iii	3.786 (3)
Na1—S1^ix	2.912 (2)	S1—S1^iv	3.786 (3)
Na1—S1^iii	2.9117 (16)
S1—Y1—S1^i	92.59 (4)	S1^vi—Na1—S1^iii	94.30 (4)
S1—Y1—S1^ii	92.59 (4)	S1^vi—Na1—S1^iv	180.0 (5)
S1—Y1—S1^iii	87.41 (4)	S1^vii—Na1—S1^viii	85.70 (4)
S1—Y1—S1^iv	87.41 (4)	S1^vii—Na1—S1^ix	94.30 (4)
S1—Y1—S1^v	180.0 (5)	S1^vii—Na1—S1^iii	180.0 (5)
S1^i—Y1—S1^ii	92.59 (4)	S1^vii—Na1—S1^iv	94.30 (4)
S1^i—Y1—S1^iii	87.41 (4)	S1^viii—Na1—S1^ix	180.0 (5)
S1^i—Y1—S1^iv	180.0 (5)	S1^viii—Na1—S1^iii	94.30 (4)
S1^i—Y1—S1^v	87.41 (4)	S1^viii—Na1—S1^iv	94.30 (4)
S1^ii—Y1—S1^iii	180.0 (5)	S1^ix—Na1—S1^iii	85.70 (4)
S1^ii—Y1—S1^iv	87.41 (4)	S1^ix—Na1—S1^iv	85.70 (4)
S1^ii—Y1—S1^v	87.41 (4)	S1^iii—Na1—S1^iv	85.70 (4)
S1^iii—Y1—S1^iv	92.59 (4)	Y1^x—S1—Y1^xii	92.59 (5)
S1^iii—Y1—S1^v	92.59 (4)	Y1^x—S1—Y1	92.59 (5)
S1^iv—Y1—S1^v	92.59 (4)	Y1^xii—S1—Y1	92.59 (5)
S1^vi—Na1—S1^vii	85.70 (4)	Na1^xiv—S1—Na1^xv	85.70 (5)
S1^vi—Na1—S1^viii	85.70 (4)	Na1^xiv—S1—Na1^xvi	85.70 (5)
S1^vi—Na1—S1^ix	94.30 (4)	Na1^xv—S1—Na1^xvi	85.70 (5)

Symmetry codes: (i) x, y+1, z; (ii) x+1, y+1, z; (iii) y−1/3, x+1/3, −z+1/3; (iv) y+2/3, x+1/3, −z+1/3; (v) y+2/3, x+4/3, −z+1/3; (vi) x−2/3, y−1/3, z−1/3; (vii) x+1/3, y−1/3, z−1/3; (viii) x+1/3, y+2/3, z−1/3; (ix) y−1/3, x−2/3, −z+1/3; (x) x−1, y−1, z; (xi) x−1, y, z; (xii) x, y−1, z; (xiii) x+1, y, z; (xiv) x−1/3, y−2/3, z+1/3; (xv) x−1/3, y+1/3, z+1/3; (xvi) x+2/3, y+1/3, z+1/3.