The new penta­borate Na₃SrB₅O₁₀

Sodium strontium penta­borate, Na₃SrB₅O₁₀, maintains the same, previously unobserved, structure type at 200, 250 and 293 K. The fundamental building units are anionic [B₅O₁₀]^5- groups distorted from mm2 point symmetry. The Sr atoms are eightfold coordinated by O atoms, forming trigonal dodeca­hedra. The Na atoms appear in three crystallographically different environments. The present single-crystal results correct a previous report in which a monoclinic cell was deduced for this compound on the basis of powder diffraction data. The structure of the title compound is discussed in the crystalochemical context of other borates with the same formula type. Although the unit cell of the present compound is similar to that determined in a previous study of the analogous Ca-containing compound, this study demonstrates that the structures of the two are different. These novel alkali-alkaline earth borates are considered as potential host materials for optical applications (fluorescence materials or phosphors).

S1. Comment

Inorganic borates have long been a focus of research due to their variety of structure types, transparency over a wide range of wavelengths, high laser damage tolerance and high optical quality. Studies of alkali metal and alkaline earth borates have produced a large family of compounds with outstanding physical properties (Becker, 1998; Chen et al., 1999), such as β-BaB₂O₄ (Chen et al., 1985), LiB₃O₅ (Chen et al., 1989), Sr₂Be₂B₂O₇ (Chen et al., 1995) and K₂Al₂B₂O₇ (Hu et al., 1999). Recently, photoluminescence has also been observed in many rare earth ion-doped alkaline earth metal borates (Pei & Su, 1993; Schaffers & Keszler, 1994; Diaz & Keszler, 1996, 1997). Some have been developed into useful phosphors, such as UV-emitting Eu²⁺-doped SrB₄O₇ [Please check rephrasing] in lamps for medical applications and skin tanning (Pei & Su, 1993). Because it has a similar radius and identical valence to Sr²⁺ and Ba²⁺, it is easy to substitute Eu²⁺ for Sr²⁺ and Ba²⁺ in crystals, giving photoluminescent doped systems. These properties depend on the crystal structures of the borates, which have a variety of [B_nO_m] polyhedral groups. The richness of their crystal chemistry and optical properties led us to explore more borates in the system M₂O–M'O–B₂O₃ (M is an alkali metal and M' is an alkaline earth metal) to search for new functional materials. Four ternary compounds, NaSrBO₃ (Wu et al., 2006), NaSr₄(BO₃)₃ (Wu et al., 2005), NaSrB₅O₉ (Wu, Zhang, Chen et al., 2007) and the title compound, Na₃SrB₅O₁₀, were found while investigating the subsolidus phase relations in the system Na₂O–SrO–B₂O₃. The space group of Na₃SrB₅O₁₀ was at first thought to be C2 based on the indexing of a powder pattern (Wu, Zhang, Chen et al., 2007). In the present study, we have employed single-crystal X-ray diffraction at various temperatures to determine and refine the structure of the title compound.

The single-crystal study at 200 K showed that crystalline Na₃SrB₅O₁₀ is in fact triclinic. As illustrated in Fig. 1, the fundamental building unit of Na₃SrB₅O₁₀ is the [B₅O₁₀]^5- group, which is composed of four [BO₃] triangles (Δ) (labelled B2, B3, B4 and B5) and one [BO₄] tetrahedron (T) (labelled B1). In the [B₅O₁₀] group, one T(B1) in the middle is connected to Δ(B2)+Δ(B4) and Δ(B3)+Δ(B5) on two sides, forming two [B₃O₃] six-membered rings approximately perpendicular to each other. A constraint to planarity for the six-membered rings was tried during structure refinement but led to a significant increase of the R value, which means that the distortion from local mm2 point symmetry for the ideal [B₅O₁₀] group is real. The four terminal O atoms lie near the planes of their respective six-membered rings, but with small deviations which lead to dihedral angles of 9.43 (14)° between Δ(B2) and Δ(B4), and 11.72 (13)° between Δ(B3) and Δ(B5) (Fig. 2). The [B₅O₁₀]^5- groups are not directly linked to each other but connected via SrO₈ and NaO_n (n = 6 or 7) polyhedra (Fig. 3), forming a complex three-dimensional array.

The Sr atoms are eight-fold coordinated by O, forming polyhedra with 12 faces. These form edge-sharing pairs, as shown in Fig. 4. Each SrO₈ polyhedron connects to five [B₅O₁₀]^5- groups through three edges and two vertices.

The Na atoms appear in three crystallographically different environments (Fig. 5). Atom Na1 is six-fold coordinated by O at distances of 2.246 (2)–2.7220 (18) Å with a bond-valence sum (Brown & Altermatt, 1985) of 1.181, forming a distorted octahedron that shares one edge and four vertices with five adjacent [B₅O₁₀]^5- groups. Two of these distorted octahedra share one edge with each other. Atom Na2 has close contacts from six O atoms at distances of 2.3210 (16)–2.705 (2) Å, and is weakly bonded to one additional O neighbour at a distance of 3.024 (2) Å. A bond-valence calculation gives sums of 0.968 and 1.005 for atom Na2 when six and seven bonds are taken into account, respectively, which means the long Na—O distance also participates in the coordination scheme, forming a distorted polyhedron with nine faces. Two of the [Na2O₇] polyhedra share a common face, and each of them shares three edges and one vertex with four neighbouring [B₅O₁₀]^5- groups. Atom Na3 is coordinated by five O atoms at distances of 2.248 (2)–2.705 (2) Å and by one further O atom at a distance of 3.151 (2) Å. The five shortest bonds give a bond-valence sum of 0.917 for atom Na3, but this increases to 0.943 when the sixth bond is taken into account, indicating that the distorted octahedron is the coordination polyhedron. Two of the [Na3O₆] polyhedra share a common edge, and each shares two edges and two vertices with four [B₅O₁₀]^5- groups.

To date, four pentaborates have been described, namely Na₃MgB₅O₁₀ (Chen, Li, Zuo et al., 2007), Na₃CaB₅O₁₀ (Fayos et al., 1985; Chen, Li, Zuo et al., 2007), Na₃SrB₅O₁₀ (this work) and Na₃ZnB₅O₁₀ (Chen, Li, Chang et al., 2007). The structure of Na₃CaB₅O₁₀ was first reported by Fayos et al. (1985). A recent study found that it had a superstructure (Chen, Li, Zuo et al., 2007) with a cell volume twice that reported previously. The present Sr-containing structure has a cell similar to that of the previously reported Ca-containing structure.

Na₃MgB₅O₁₀ crystallizes in the orthorhombic space group Pbca, and Na₃ZnB₅O₁₀ crystallizes in the monoclinic space group P2₁/n. The fundamental building unit of the calcium and strontium pentaborates is the isolated polyanionic group [B₅O₁₀]^5-, but none of the six-membered rings with terminal O atoms is rigorously planar; they are distorted and only approximately perpendicular to each other. The dihedral angles formed by the six-membered rings are 88.41 (6)° and 88.02 (7)/89.63 (7)° for Na₃SrB₅O₁₀ and Na₃CaB₅O₁₀, respectively. In contrast with the Sr- and Ca-containing borates, in which the [B₅O₁₀]^5- groups exist as discrete residues, the [B₅O₁₀]^5- groups in the Mg- and Zn-containing compounds are bridged by [MgO₄] or [ZnO₄], and form infinite two-dimensional [MgB₅O₁₀]^3- and [ZnB₅O₁₀]^3- layers. Another difference between the Mg-, Ca-, Sr- and Zn-containing compounds relates to the coordination polyhedra of the divalent cations. Both Mg and Zn atoms are four-coordinate. The [SrO₈] coordination polyhedron connects five adjacent [B₅O₁₀] groups by sharing three edges and two vertices with [BO₃], while the [CaO₆] octahedron shares one edge with [BO₄] and four vertices with [BO₃] to bridge five [B₅O₁₀] groups. The coordination environment of Ca in Na₃CaB₅O₁₀ is similar to that of atom Na1 in the title compound, as the sites analogous to those occupied by Ca in Na₃CaB₅O₁₀ are occupied by atom Na1 in Na₃SrB₅O₁₀. Because of the different valences of the alkali metal (Na1) and alkaline earth (Ca) cations, the M—O distances are different, in such a way as to reduce the bond valence of the position occupied by Na⁺ and improve the bond valence for Sr²⁺, which is accompanied by a small change in the orientation of the [B₅O₁₀] groups. Some changes are also observed in the environments of the O atoms. A similar situation has been found in NaMgBO₃ (Wu, Zhang, Kong et al., 2007) and NaSrBO₃, in which the alkali metal and alkaline earth metal atoms exchange positions. As for the Na atoms, they appear in three crystallographically distinct environments in every one of the four borates. In the magnesium pentaborate, all of them are seven-coordinate, but with different coordination polyhedra. In the calcium pentaborate, they are seven-, six- and five-coordinate (Chen, Li, Zuo et al., 2007). In the strontium pentaborate, they are six-, seven- and six-coordinate and, as mentioned above, give the correct bond valences, even with two unusually long distances to the surrounding O atoms. In the Zn pentaborate, they are eight-, seven- and six-coordinate. It is likely that the different combinations of Mg—O, Ca—O, Sr—O, Zn—O and Na—O bonds cause the six-membered rings to show different degrees of distortion in the different structures.

These borates form stable doped systems, without a reducing atmosphere, when the divalent cations are replaced by rare earth ions (Pei & Su, 1993) such as Eu²⁺. It is known that Eu²⁺-doped borates will show various emissions when the dopant is placed in different O-atom environments (Diaz & Keszler, 1997). Considering the different environments of the divalent cations and the O atoms in the four pentaborates, it is reasonable to expect photoluminescence with different emissions for these systems when doped with Eu²⁺.

S2. Experimental

Polycrystalline samples were prepared by solid-state reactions conducted by sintering at high temperature. Mixtures of analytical purity Na₂CO₃, SrCO₃ and H₃BO₃ were heated to 873 K to decompose the carbonate and eliminate water, and then elevated to the sintering temperature of 1073 K for 72 h. Between sintering steps, the samples were cooled and ground. The pure powder sample was compacted, then placed in a Pt crucible and fired at 1123 K for 48 h. It was then cooled to 553 K and taken out of the furnace. Small transparent single crystals could be selected from the compacted sample.

S3. Refinement

Single-crystal data for Na₃SrB₅O₁₀ were collected on a Stoe IPDS II single-crystal diffractometer (Mo Kα). The unit cell was first determined from a powder pattern using DICVOL91 (Boultif & Louër, 1991) by the successive dichotomy method with Si as the internal standard. This gave a monoclinic unit cell with a = 7.290 (1) Å, b = 13.442 (2) Å, c = 9.792 (1) Å and β = 109.60 (1)° [ICDD (ICDD, 2005) PDF 56-0146]. Based on the systematic absences, the possible space groups were deduced to be C2, Cm or C2/m (Wu, Zhang, Chen et al., 2007). The present single-crystal study at 200 K showed that the actual unit cell is triclinic, with cell constants similar to those of the reduced cell of the previously reported structure of Na₃CaB₅O₁₀ (Fayos et al., 1985). The structure was solved by direct methods and refined by full matrix least-squares techniques, with anisotropic thermal parameters for all atoms. Calculated radial distribution functions (PLATON; Spek, 2003) indicated that the title compound and the analogous Ca compound are not isomorphous. The structure was also investigated at different temperatures (250 and 293 K; data available in the archived CIF), with very similar results and no indication of a possible phase transition in this temperature interval.

Computing details

For all compounds, data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-AREA (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Balls&Sticks (Version 1.42; Ozawa & Kang, 2004); software used to prepare material for publication: WinGX (Version 1.64; Farrugia, 1999).

Figures

	Fig. 1. Projection of the structure of Na3SrB5O10, viewed along [100].
	Fig. 2. The [B5O10]^5- group.
	Fig. 3. A view of the [B5O10]^5- group and the adjacent Na and Sr coordination. [Symmetry codes: (i) x + 1, y, z; (ii) x, y - 1, z; (iii) -x, 1 - y, 1 - z; (iv) 1 - x, 1 - y, 1 - z; (v) -x, 2 - y, 1 - z; (vi) 1 - x, 2 - y, 1 - z; (vii) 1 - x, -y, -z; (viii) 1 - x, 1 - y, -z; (ix) x, y, z + 1; (x)-x, 1 - y, -z.]
	Fig. 4. The SrO8 coordination polyhedra.
	Fig. 5. The Na1O6, Na2O7 and Na3O6 coordination polyhedra.

(I_200K) sodium strontium pentaborate

Crystal data

Na3SrB5O10	Z = 2
Mr = 370.64	F(000) = 352
Triclinic, P1	Dx = 2.757 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.277 (2) Å	Cell parameters from 4273 reflections
b = 7.601 (2) Å	θ = 3.2–36.3°
c = 9.728 (2) Å	µ = 6.23 mm^−1
α = 81.062 (16)°	T = 200 K
β = 70.538 (15)°	Plate, colourless
γ = 61.636 (15)°	0.1 × 0.1 × 0.02 mm
V = 446.43 (19) Å^3

Data collection

Stoe IPDS II diffractometer	2049 independent reflections
Radiation source: fine-focus sealed tube	1595 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.136
rotation method, ω scans	θmax = 27.5°, θmin = 3.4°
Absorption correction: numerical via equivalents (X-SHAPE and X-RED; Stoe & Cie, 1996)	h = −9→9
Tmin = 0.335, Tmax = 0.511	k = −9→9
11007 measured reflections	l = −12→12

Refinement

Refinement on F^2	4 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.050	Secondary atom site location: difference Fourier map
wR(F^2) = 0.089	w = 1/[σ^2(Fo^2) + (0.0253P)^2 + 2.0814P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max = 0.001
2049 reflections	Δρmax = 0.75 e Å^−3
172 parameters	Δρmin = −0.94 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Sr1	0.21356 (3)	0.94626 (3)	0.77505 (2)	0.00583 (4)
Na1	0.27930 (12)	0.01508 (12)	0.11506 (10)	0.0098 (2)
Na2	0.84487 (13)	0.50424 (13)	0.16342 (10)	0.0133 (2)
Na3	0.20961 (14)	0.27520 (17)	0.45000 (11)	0.0281 (3)
O1	0.1689 (2)	0.75187 (19)	0.18955 (16)	0.0063 (4)
O2	0.6608 (2)	0.8048 (2)	0.35726 (17)	0.0139 (4)
O3	0.0139 (2)	0.7955 (2)	−0.00078 (17)	0.0098 (4)
O4	0.1567 (2)	0.6537 (2)	0.43867 (16)	0.0087 (4)
O5	0.4064 (2)	0.4137 (2)	0.25015 (16)	0.0095 (4)
O6	0.4711 (2)	0.6865 (2)	0.27103 (17)	0.0099 (4)
O7	0.3177 (2)	0.8224 (2)	0.51172 (17)	0.0141 (4)
O8	0.5042 (2)	0.1443 (2)	0.10496 (17)	0.0091 (4)
O9	0.2335 (2)	0.4699 (2)	0.06442 (17)	0.0100 (4)
O10	0.0226 (2)	0.7791 (2)	0.68077 (17)	0.0125 (4)
B1	0.3029 (3)	0.6274 (3)	0.2883 (3)	0.0076 (6)
B2	0.3855 (3)	0.3365 (3)	0.1369 (3)	0.0078 (6)
B3	0.4894 (3)	0.7713 (3)	0.3780 (3)	0.0087 (6)
B4	0.1401 (3)	0.6753 (3)	0.0809 (3)	0.0086 (6)
B5	0.1597 (3)	0.7518 (3)	0.5465 (3)	0.0083 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr1	0.00487 (5)	0.00737 (6)	0.00545 (7)	−0.00267 (4)	−0.00163 (5)	−0.00075 (5)
Na1	0.0075 (3)	0.0112 (3)	0.0111 (4)	−0.0056 (2)	−0.0002 (3)	−0.0022 (3)
Na2	0.0101 (3)	0.0174 (3)	0.0125 (4)	−0.0052 (2)	−0.0038 (3)	−0.0026 (3)
Na3	0.0225 (3)	0.0598 (5)	0.0144 (4)	−0.0288 (3)	−0.0097 (3)	0.0111 (4)
O1	0.0091 (4)	0.0043 (5)	0.0085 (6)	−0.0038 (4)	−0.0041 (4)	−0.0016 (4)
O2	0.0172 (5)	0.0225 (6)	0.0113 (7)	−0.0147 (4)	−0.0093 (5)	0.0056 (5)
O3	0.0090 (5)	0.0124 (6)	0.0101 (6)	−0.0046 (4)	−0.0050 (4)	−0.0016 (5)
O4	0.0088 (5)	0.0133 (5)	0.0045 (6)	−0.0067 (4)	0.0010 (4)	−0.0022 (5)
O5	0.0123 (5)	0.0073 (5)	0.0104 (6)	−0.0016 (4)	−0.0074 (4)	−0.0043 (5)
O6	0.0093 (5)	0.0147 (5)	0.0066 (6)	−0.0071 (4)	0.0004 (4)	−0.0031 (5)
O7	0.0154 (5)	0.0236 (6)	0.0085 (7)	−0.0144 (4)	0.0004 (5)	−0.0044 (5)
O8	0.0080 (5)	0.0075 (5)	0.0142 (7)	−0.0047 (4)	−0.0038 (5)	−0.0009 (5)
O9	0.0126 (5)	0.0065 (5)	0.0090 (6)	−0.0005 (4)	−0.0057 (5)	−0.0024 (5)
O10	0.0128 (5)	0.0162 (6)	0.0080 (7)	−0.0058 (4)	−0.0018 (5)	−0.0042 (5)
B1	0.0076 (7)	0.0061 (8)	0.0080 (10)	−0.0031 (6)	−0.0007 (7)	−0.0010 (7)
B2	0.0120 (7)	0.0116 (8)	0.0038 (9)	−0.0093 (6)	−0.0020 (7)	0.0018 (7)
B3	0.0104 (7)	0.0089 (8)	0.0065 (10)	−0.0045 (6)	−0.0020 (7)	0.0002 (7)
B4	0.0104 (7)	0.0113 (8)	0.0086 (9)	−0.0065 (6)	−0.0048 (6)	−0.0019 (7)
B5	0.0045 (7)	0.0097 (8)	0.0100 (10)	−0.0031 (6)	−0.0018 (7)	0.0007 (8)

Geometric parameters (Å, º)

Sr1—O8^i	2.4613 (18)	Na3—O4^vii	2.3366 (18)
Sr1—O2^ii	2.4847 (18)	Na3—O5	2.4247 (19)
Sr1—O1^iii	2.5823 (14)	Na3—O10^vii	2.627 (2)
Sr1—O7	2.6080 (18)	Na3—O4	2.705 (2)
Sr1—O3^iv	2.6219 (16)	Na3—O7^vi	3.151 (2)
Sr1—O3^iii	2.6918 (17)	B1—O1	1.495 (3)
Sr1—O10	2.697 (2)	B1—O4	1.471 (3)
Sr1—O5^i	2.7858 (15)	B1—O5	1.477 (3)
Na1—O8	2.246 (2)	B1—O6	1.445 (3)
Na1—O8^v	2.2971 (18)	B2—O5	1.406 (3)
Na1—O1^vi	2.4213 (19)	B2—O8	1.319 (2)
Na1—O10^vii	2.4515 (17)	B2—O9	1.407 (3)
Na1—O3^viii	2.4549 (19)	B3—O2	1.334 (3)
Na1—O6^vi	2.7220 (18)	B3—O6	1.378 (3)
Na2—O6	2.3210 (16)	B3—O7	1.420 (3)
Na2—O10^i	2.4194 (18)	B4—O1	1.398 (3)
Na2—O9^ix	2.424 (2)	B4—O3	1.331 (3)
Na2—O9^x	2.560 (2)	B4—O9	1.387 (3)
Na2—O3^ix	2.561 (2)	B5—O4	1.390 (3)
Na2—O2	2.705 (2)	B5—O7	1.412 (3)
Na2—O3^x	3.024 (2)	B5—O10	1.328 (3)
Na3—O2^i	2.248 (2)
O8^i—Sr1—O2^ii	84.61 (6)	O6—Na2—O3^ix	119.26 (8)
O8^i—Sr1—O1^iii	131.51 (5)	O10^i—Na2—O3^ix	76.87 (6)
O2^ii—Sr1—O1^iii	82.93 (5)	O9^ix—Na2—O3^ix	56.10 (5)
O8^i—Sr1—O7	121.01 (5)	O9^x—Na2—O3^ix	86.32 (6)
O2^ii—Sr1—O7	82.81 (6)	O6—Na2—O2	55.57 (6)
O1^iii—Sr1—O7	103.58 (5)	O10^i—Na2—O2	99.69 (6)
O8^i—Sr1—O3^iv	88.27 (6)	O9^ix—Na2—O2	125.50 (6)
O2^ii—Sr1—O3^iv	155.96 (5)	O9^x—Na2—O2	99.78 (7)
O1^iii—Sr1—O3^iv	84.72 (5)	O3^ix—Na2—O2	172.97 (6)
O7—Sr1—O3^iv	120.23 (6)	O6—Na2—O3^x	107.50 (6)
O8^i—Sr1—O3^iii	79.14 (5)	O10^i—Na2—O3^x	134.01 (7)
O2^ii—Sr1—O3^iii	86.82 (5)	O9^ix—Na2—O3^x	79.20 (6)
O1^iii—Sr1—O3^iii	53.55 (5)	O9^x—Na2—O3^x	48.86 (5)
O7—Sr1—O3^iii	156.06 (5)	O3^ix—Na2—O3^x	110.21 (5)
O3^iv—Sr1—O3^iii	69.27 (6)	O2—Na2—O3^x	76.63 (6)
O8^i—Sr1—O10	140.66 (5)	O2^i—Na3—O4^vii	101.74 (7)
O2^ii—Sr1—O10	126.57 (6)	O2^i—Na3—O5	112.70 (8)
O1^iii—Sr1—O10	80.93 (5)	O4^vii—Na3—O5	135.81 (7)
O7—Sr1—O10	52.81 (5)	O2^i—Na3—O10^vii	145.70 (8)
O3^iv—Sr1—O10	71.23 (6)	O4^vii—Na3—O10^vii	57.08 (6)
O3^iii—Sr1—O10	120.90 (5)	O5—Na3—O10^vii	99.97 (7)
O8^i—Sr1—O5^i	52.85 (5)	O2^i—Na3—O4	93.27 (8)
O2^ii—Sr1—O5^i	105.25 (5)	O4^vii—Na3—O4	97.70 (6)
O1^iii—Sr1—O5^i	171.55 (5)	O5—Na3—O4	54.96 (5)
O7—Sr1—O5^i	75.82 (5)	O10^vii—Na3—O4	114.69 (6)
O3^iv—Sr1—O5^i	88.35 (5)	O2^i—Na3—O7^vi	75.17 (7)
O3^iii—Sr1—O5^i	127.90 (5)	O4^vii—Na3—O7^vi	86.28 (6)
O10—Sr1—O5^i	92.28 (5)	O5—Na3—O7^vi	127.94 (5)
O8—Na1—O8^v	91.51 (7)	O10^vii—Na3—O7^vi	76.67 (6)
O8—Na1—O1^vi	150.22 (6)	O4—Na3—O7^vi	168.35 (7)
O8^v—Na1—O1^vi	89.43 (6)	O6—B1—O4	112.6 (2)
O8—Na1—O10^vii	96.56 (7)	O6—B1—O5	109.32 (15)
O8^v—Na1—O10^vii	165.69 (7)	O4—B1—O5	107.64 (17)
O1^vi—Na1—O10^vii	89.40 (6)	O6—B1—O1	108.75 (18)
O8—Na1—O3^viii	117.81 (7)	O4—B1—O1	108.52 (14)
O8^v—Na1—O3^viii	87.48 (6)	O5—B1—O1	110.0 (2)
O1^vi—Na1—O3^viii	91.96 (7)	O8—B2—O5	119.35 (19)
O10^vii—Na1—O3^viii	78.31 (6)	O8—B2—O9	123.0 (2)
O8—Na1—O6^vi	95.24 (6)	O5—B2—O9	117.66 (17)
O8^v—Na1—O6^vi	93.20 (6)	O2—B3—O6	121.60 (18)
O1^vi—Na1—O6^vi	55.00 (6)	O2—B3—O7	121.1 (2)
O10^vii—Na1—O6^vi	97.79 (6)	O6—B3—O7	117.3 (2)
O3^viii—Na1—O6^vi	146.92 (7)	O3—B4—O9	119.4 (2)
O6—Na2—O10^i	107.24 (6)	O3—B4—O1	121.22 (19)
O6—Na2—O9^ix	87.57 (6)	O9—B4—O1	119.22 (19)
O10^i—Na2—O9^ix	131.32 (7)	O10—B5—O4	122.7 (2)
O6—Na2—O9^x	152.17 (7)	O10—B5—O7	119.0 (2)
O10^i—Na2—O9^x	88.18 (6)	O4—B5—O7	118.32 (18)
O9^ix—Na2—O9^x	99.64 (6)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+2, −z+1; (iii) −x, −y+2, −z+1; (iv) x, y, z+1; (v) −x+1, −y, −z; (vi) x, y−1, z; (vii) −x, −y+1, −z+1; (viii) −x, −y+1, −z; (ix) −x+1, −y+1, −z; (x) x+1, y, z.

(I_250K) sodium strontium pentaborate

Crystal data

Na3SrB5O10	Z = 2
Mr = 370.64	F(000) = 352
Triclinic, P1	Dx = 2.753 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.279 (2) Å	Cell parameters from 4273 reflections
b = 7.601 (1) Å	θ = 3.2–36.0°
c = 9.735 (2) Å	µ = 6.22 mm^−1
α = 81.092 (16)°	T = 250 K
β = 70.565 (15)°	Plate, colourless
γ = 61.668 (14)°	0.1 × 0.1 × 0.02 mm
V = 447.08 (16) Å^3

Data collection

Stoe IPDS II diffractometer	2373 independent reflections
Radiation source: fine-focus sealed tube	1704 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.150
rotation method, ω scans	θmax = 29.0°, θmin = 3.4°
Absorption correction: numerical via equivalents (X-SHAPE and X-RED; Stoe & Cie, 1996)	h = −9→9
Tmin = 0.336, Tmax = 0.512	k = −10→10
9384 measured reflections	l = −13→13

Refinement

Refinement on F^2	4 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.058	Secondary atom site location: difference Fourier map
wR(F^2) = 0.101	w = 1/[σ^2(Fo^2) + (0.0205P)^2 + 0.9553P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.001
2373 reflections	Δρmax = 0.82 e Å^−3
172 parameters	Δρmin = −0.84 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Sr1	0.21377 (3)	0.94601 (3)	0.77508 (3)	0.00788 (4)
Na1	0.27987 (13)	0.01465 (13)	0.11480 (11)	0.0138 (2)
Na2	0.84428 (14)	0.50530 (14)	0.16329 (11)	0.0167 (3)
Na3	0.20999 (15)	0.27453 (19)	0.45095 (12)	0.0323 (3)
O1	0.1678 (2)	0.7515 (2)	0.19046 (17)	0.0104 (4)
O2	0.6601 (2)	0.8063 (2)	0.3564 (2)	0.0169 (5)
O3	0.0130 (2)	0.7946 (2)	0.00001 (18)	0.0106 (4)
O4	0.1567 (2)	0.6536 (2)	0.43872 (17)	0.0109 (4)
O5	0.4070 (2)	0.4138 (2)	0.24946 (18)	0.0107 (4)
O6	0.4697 (2)	0.6880 (2)	0.27158 (18)	0.0137 (4)
O7	0.3165 (2)	0.8224 (2)	0.5118 (2)	0.0171 (5)
O8	0.5043 (2)	0.1454 (2)	0.10460 (19)	0.0112 (4)
O9	0.2353 (2)	0.4693 (2)	0.06457 (18)	0.0128 (4)
O10	0.0225 (2)	0.7795 (2)	0.68161 (18)	0.0142 (5)
B1	0.3019 (4)	0.6277 (4)	0.2872 (3)	0.0107 (6)
B2	0.3865 (3)	0.3369 (4)	0.1374 (3)	0.0103 (6)
B3	0.4899 (4)	0.7739 (3)	0.3788 (3)	0.0112 (6)
B4	0.1393 (3)	0.6766 (3)	0.0818 (3)	0.0076 (6)
B5	0.1562 (3)	0.7510 (3)	0.5474 (3)	0.0073 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr1	0.00677 (5)	0.00945 (6)	0.00757 (7)	−0.00327 (4)	−0.00249 (5)	−0.00099 (5)
Na1	0.0126 (3)	0.0171 (3)	0.0136 (4)	−0.0085 (2)	−0.0024 (3)	−0.0027 (3)
Na2	0.0145 (3)	0.0215 (4)	0.0155 (4)	−0.0090 (3)	−0.0041 (3)	−0.0019 (3)
Na3	0.0281 (4)	0.0680 (6)	0.0156 (5)	−0.0343 (3)	−0.0107 (3)	0.0127 (4)
O1	0.0126 (5)	0.0114 (6)	0.0082 (7)	−0.0043 (4)	−0.0058 (5)	−0.0009 (5)
O2	0.0194 (5)	0.0236 (7)	0.0176 (8)	−0.0154 (4)	−0.0112 (5)	0.0055 (6)
O3	0.0116 (5)	0.0124 (6)	0.0094 (7)	−0.0048 (4)	−0.0054 (5)	−0.0012 (5)
O4	0.0109 (5)	0.0207 (6)	0.0053 (6)	−0.0102 (4)	−0.0009 (4)	−0.0042 (5)
O5	0.0125 (5)	0.0054 (6)	0.0135 (7)	−0.0008 (4)	−0.0069 (5)	−0.0023 (5)
O6	0.0131 (5)	0.0252 (6)	0.0070 (7)	−0.0131 (4)	0.0004 (5)	−0.0043 (5)
O7	0.0161 (5)	0.0271 (7)	0.0131 (8)	−0.0154 (4)	0.0002 (5)	−0.0044 (6)
O8	0.0076 (5)	0.0084 (6)	0.0168 (7)	−0.0012 (4)	−0.0050 (5)	−0.0027 (5)
O9	0.0211 (6)	0.0090 (6)	0.0112 (7)	−0.0052 (4)	−0.0096 (5)	−0.0028 (5)
O10	0.0158 (6)	0.0185 (7)	0.0080 (7)	−0.0064 (5)	−0.0034 (5)	−0.0047 (5)
B1	0.0110 (8)	0.0087 (8)	0.0126 (10)	−0.0027 (6)	−0.0044 (7)	−0.0042 (8)
B2	0.0095 (7)	0.0139 (9)	0.0088 (10)	−0.0065 (6)	−0.0026 (7)	0.0000 (8)
B3	0.0198 (8)	0.0083 (8)	0.0070 (10)	−0.0095 (6)	−0.0024 (8)	0.0027 (8)
B4	0.0060 (7)	0.0110 (8)	0.0058 (10)	−0.0038 (6)	−0.0020 (7)	0.0009 (7)
B5	0.0042 (6)	0.0089 (8)	0.0113 (10)	−0.0026 (6)	−0.0045 (6)	−0.0028 (7)

Geometric parameters (Å, º)

Sr1—O8^i	2.462 (2)	Na3—O4^vii	2.3380 (19)
Sr1—O2^ii	2.478 (2)	Na3—O5	2.440 (2)
Sr1—O1^iii	2.5826 (15)	Na3—O10^vii	2.641 (3)
Sr1—O7	2.610 (2)	Na3—O4	2.708 (2)
Sr1—O3^iv	2.6345 (17)	Na3—O7^vi	3.147 (2)
Sr1—O10	2.691 (2)	B1—O1	1.480 (3)
Sr1—O3^iii	2.6924 (17)	B1—O4	1.479 (3)
Sr1—O5^i	2.7849 (15)	B1—O5	1.477 (3)
Na1—O8	2.252 (2)	B1—O6	1.453 (4)
Na1—O8^v	2.2952 (19)	B2—O5	1.394 (4)
Na1—O1^vi	2.429 (2)	B2—O8	1.316 (3)
Na1—O10^vii	2.4514 (18)	B2—O9	1.405 (3)
Na1—O3^viii	2.459 (2)	B3—O2	1.317 (4)
Na1—O6^vi	2.7161 (19)	B3—O6	1.394 (4)
Na2—O6	2.3283 (17)	B3—O7	1.423 (3)
Na2—O10^i	2.4239 (19)	B4—O1	1.389 (4)
Na2—O9^ix	2.431 (2)	B4—O3	1.329 (3)
Na2—O3^ix	2.565 (2)	B4—O9	1.399 (3)
Na2—O9^x	2.574 (2)	B5—O4	1.380 (3)
Na2—O2	2.704 (2)	B5—O7	1.432 (3)
Na2—O3^x	3.009 (2)	B5—O10	1.320 (3)
Na3—O2^i	2.249 (2)
O8^i—Sr1—O2^ii	84.64 (6)	O6—Na2—O9^x	152.30 (8)
O8^i—Sr1—O1^iii	131.61 (6)	O10^i—Na2—O9^x	87.89 (6)
O2^ii—Sr1—O1^iii	82.85 (5)	O9^ix—Na2—O9^x	99.99 (7)
O8^i—Sr1—O7	121.20 (5)	O3^ix—Na2—O9^x	85.99 (6)
O2^ii—Sr1—O7	82.93 (6)	O6—Na2—O2	55.43 (7)
O1^iii—Sr1—O7	103.31 (6)	O10^i—Na2—O2	100.06 (7)
O8^i—Sr1—O3^iv	88.16 (6)	O9^ix—Na2—O2	125.40 (6)
O2^ii—Sr1—O3^iv	155.95 (6)	O3^ix—Na2—O2	173.24 (7)
O1^iii—Sr1—O3^iv	84.92 (5)	O9^x—Na2—O2	99.88 (7)
O7—Sr1—O3^iv	120.13 (6)	O6—Na2—O3^x	107.59 (6)
O8^i—Sr1—O10	140.51 (5)	O10^i—Na2—O3^x	134.01 (7)
O2^ii—Sr1—O10	126.77 (6)	O9^ix—Na2—O3^x	79.42 (6)
O1^iii—Sr1—O10	80.92 (6)	O3^ix—Na2—O3^x	109.96 (6)
O7—Sr1—O10	52.80 (6)	O9^x—Na2—O3^x	49.04 (5)
O3^iv—Sr1—O10	71.09 (6)	O2—Na2—O3^x	76.61 (6)
O8^i—Sr1—O3^iii	79.17 (5)	O2^i—Na3—O4^vii	101.99 (7)
O2^ii—Sr1—O3^iii	86.59 (6)	O2^i—Na3—O5	113.00 (9)
O1^iii—Sr1—O3^iii	53.60 (6)	O4^vii—Na3—O5	135.40 (7)
O7—Sr1—O3^iii	155.81 (5)	O2^i—Na3—O10^vii	145.87 (9)
O3^iv—Sr1—O3^iii	69.51 (7)	O4^vii—Na3—O10^vii	57.13 (6)
O10—Sr1—O3^iii	120.91 (5)	O5—Na3—O10^vii	99.45 (7)
O8^i—Sr1—O5^i	52.70 (6)	O2^i—Na3—O4	93.63 (8)
O2^ii—Sr1—O5^i	105.22 (5)	O4^vii—Na3—O4	97.56 (7)
O1^iii—Sr1—O5^i	171.66 (6)	O5—Na3—O4	54.92 (6)
O7—Sr1—O5^i	76.06 (5)	O10^vii—Na3—O4	114.33 (7)
O3^iv—Sr1—O5^i	88.26 (5)	O2^i—Na3—O7^vi	75.25 (7)
O10—Sr1—O5^i	92.35 (5)	O4^vii—Na3—O7^vi	86.32 (7)
O3^iii—Sr1—O5^i	127.89 (5)	O5—Na3—O7^vi	127.94 (6)
O8—Na1—O8^v	91.73 (8)	O10^vii—Na3—O7^vi	76.61 (7)
O8—Na1—O1^vi	150.45 (7)	O4—Na3—O7^vi	168.79 (7)
O8^v—Na1—O1^vi	89.53 (7)	O6—B1—O5	109.22 (16)
O8—Na1—O10^vii	96.56 (8)	O6—B1—O4	111.5 (2)
O8^v—Na1—O10^vii	165.53 (8)	O5—B1—O4	107.61 (19)
O1^vi—Na1—O10^vii	89.08 (7)	O6—B1—O1	109.2 (2)
O8—Na1—O3^viii	117.35 (7)	O5—B1—O1	110.7 (2)
O8^v—Na1—O3^viii	87.49 (7)	O4—B1—O1	108.58 (16)
O1^vi—Na1—O3^viii	92.20 (7)	O8—B2—O5	119.9 (2)
O10^vii—Na1—O3^viii	78.18 (6)	O8—B2—O9	122.3 (3)
O8—Na1—O6^vi	95.43 (7)	O5—B2—O9	117.75 (19)
O8^v—Na1—O6^vi	93.38 (6)	O2—B3—O6	121.3 (2)
O1^vi—Na1—O6^vi	55.03 (6)	O2—B3—O7	123.1 (3)
O10^vii—Na1—O6^vi	97.60 (6)	O6—B3—O7	115.6 (2)
O3^viii—Na1—O6^vi	147.18 (8)	O3—B4—O1	122.2 (2)
O6—Na2—O10^i	107.28 (7)	O3—B4—O9	118.9 (2)
O6—Na2—O9^ix	87.55 (7)	O1—B4—O9	118.7 (2)
O10^i—Na2—O9^ix	130.96 (8)	O10—B5—O4	125.0 (2)
O6—Na2—O3^ix	119.56 (8)	O10—B5—O7	117.9 (2)
O10^i—Na2—O3^ix	76.67 (6)	O4—B5—O7	117.12 (18)
O9^ix—Na2—O3^ix	56.05 (6)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+2, −z+1; (iii) −x, −y+2, −z+1; (iv) x, y, z+1; (v) −x+1, −y, −z; (vi) x, y−1, z; (vii) −x, −y+1, −z+1; (viii) −x, −y+1, −z; (ix) −x+1, −y+1, −z; (x) x+1, y, z.

(I_293K) sodium strontium pentaborate

Crystal data

Na3SrB5O10	Z = 2
Mr = 370.64	F(000) = 352
Triclinic, P1	Dx = 2.738 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.288 (7) Å	Cell parameters from 4273 reflections
b = 7.611 (8) Å	θ = 3.3–36.6°
c = 9.754 (9) Å	µ = 6.19 mm^−1
α = 81.28 (8)°	T = 293 K
β = 70.72 (7)°	Plate, colourless
γ = 61.68 (7)°	0.1 × 0.1 × 0.02 mm
V = 449.6 (8) Å^3

Data collection

Stoe IPDS II diffractometer	2385 independent reflections
Radiation source: fine-focus sealed tube	1720 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.169
rotation method, ω scans	θmax = 29.0°, θmin = 3.4°
Absorption correction: numerical via equivalents (X-SHAPE and X-RED; Stoe & Cie, 1996)	h = −9→9
Tmin = 0.337, Tmax = 0.513	k = −10→10
12682 measured reflections	l = −13→13

Refinement

Refinement on F^2	4 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.059	Secondary atom site location: difference Fourier map
wR(F^2) = 0.103	w = 1/[σ^2(Fo^2) + (0.0043P)^2 + 2.9499P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.001
2385 reflections	Δρmax = 0.81 e Å^−3
172 parameters	Δρmin = −0.88 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Sr1	0.21411 (4)	0.94587 (4)	0.77498 (3)	0.00979 (5)
Na1	0.28038 (14)	0.01532 (14)	0.11510 (11)	0.0169 (3)
Na2	0.84288 (15)	0.50640 (15)	0.16291 (11)	0.0198 (3)
Na3	0.21044 (17)	0.2735 (2)	0.45066 (13)	0.0393 (4)
O1	0.1670 (2)	0.7517 (2)	0.19082 (18)	0.0124 (4)
O2	0.6565 (3)	0.8091 (3)	0.35669 (19)	0.0214 (5)
O3	0.0128 (2)	0.7943 (2)	0.00059 (19)	0.0148 (5)
O4	0.1571 (2)	0.6544 (2)	0.43896 (18)	0.0154 (5)
O5	0.4057 (2)	0.4141 (2)	0.25037 (18)	0.0127 (4)
O6	0.4684 (2)	0.6885 (2)	0.27235 (18)	0.0153 (4)
O7	0.3180 (2)	0.8204 (3)	0.51151 (19)	0.0195 (5)
O8	0.5048 (2)	0.1457 (2)	0.10438 (19)	0.0152 (5)
O9	0.2335 (3)	0.4701 (2)	0.06535 (19)	0.0168 (5)
O10	0.0234 (2)	0.7786 (2)	0.68105 (18)	0.0165 (5)
B1	0.2991 (3)	0.6283 (3)	0.2900 (3)	0.0086 (6)
B2	0.3857 (4)	0.3382 (4)	0.1369 (3)	0.0111 (6)
B3	0.4908 (4)	0.7722 (4)	0.3776 (3)	0.0122 (6)
B4	0.1399 (4)	0.6760 (4)	0.0818 (3)	0.0111 (7)
B5	0.1595 (4)	0.7502 (4)	0.5472 (3)	0.0127 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sr1	0.00882 (5)	0.01152 (6)	0.00956 (7)	−0.00452 (4)	−0.00299 (5)	−0.00120 (6)
Na1	0.0139 (3)	0.0229 (4)	0.0150 (4)	−0.0110 (3)	−0.0002 (3)	−0.0034 (3)
Na2	0.0176 (3)	0.0276 (4)	0.0148 (4)	−0.0110 (3)	−0.0033 (3)	−0.0022 (4)
Na3	0.0320 (4)	0.0812 (7)	0.0214 (5)	−0.0400 (4)	−0.0132 (4)	0.0167 (5)
O1	0.0158 (6)	0.0075 (6)	0.0143 (7)	−0.0039 (4)	−0.0062 (5)	−0.0020 (5)
O2	0.0267 (6)	0.0380 (8)	0.0132 (8)	−0.0242 (5)	−0.0108 (5)	0.0066 (6)
O3	0.0163 (6)	0.0146 (6)	0.0139 (7)	−0.0055 (5)	−0.0075 (5)	0.0000 (6)
O4	0.0171 (6)	0.0234 (7)	0.0082 (7)	−0.0120 (5)	−0.0002 (5)	−0.0052 (6)
O5	0.0153 (5)	0.0109 (6)	0.0116 (7)	−0.0016 (5)	−0.0087 (5)	−0.0036 (5)
O6	0.0165 (5)	0.0259 (6)	0.0108 (7)	−0.0152 (4)	−0.0012 (5)	−0.0066 (5)
O7	0.0207 (6)	0.0336 (7)	0.0146 (8)	−0.0202 (5)	−0.0020 (5)	−0.0079 (6)
O8	0.0143 (5)	0.0114 (6)	0.0217 (8)	−0.0047 (4)	−0.0091 (5)	−0.0007 (6)
O9	0.0240 (6)	0.0130 (6)	0.0174 (7)	−0.0068 (5)	−0.0130 (5)	−0.0011 (6)
O10	0.0194 (6)	0.0237 (7)	0.0100 (7)	−0.0115 (5)	−0.0057 (5)	−0.0011 (6)
B1	0.0126 (7)	0.0105 (8)	0.0090 (9)	−0.0080 (6)	−0.0053 (6)	−0.0022 (7)
B2	0.0121 (8)	0.0131 (9)	0.0098 (10)	−0.0061 (6)	−0.0033 (7)	−0.0024 (8)
B3	0.0179 (8)	0.0139 (9)	0.0102 (10)	−0.0110 (6)	−0.0079 (7)	0.0065 (8)
B4	0.0101 (8)	0.0114 (9)	0.0108 (11)	−0.0057 (6)	−0.0025 (8)	0.0043 (8)
B5	0.0117 (8)	0.0110 (9)	0.0153 (11)	−0.0020 (7)	−0.0084 (7)	−0.0004 (8)

Geometric parameters (Å, º)

Sr1—O8^i	2.460 (3)	Na3—O4^vii	2.348 (3)
Sr1—O2^ii	2.482 (3)	Na3—O5	2.442 (3)
Sr1—O1^iii	2.584 (4)	Na3—O10^vii	2.637 (3)
Sr1—O7	2.620 (3)	Na3—O4	2.725 (4)
Sr1—O3^iv	2.652 (3)	Na3—O7^vi	3.159 (4)
Sr1—O3^iii	2.694 (4)	B1—O1	1.492 (3)
Sr1—O10	2.695 (3)	B1—O4	1.456 (3)
Sr1—O5^i	2.792 (4)	B1—O5	1.484 (3)
Na1—O8	2.251 (3)	B1—O6	1.461 (4)
Na1—O8^v	2.302 (4)	B2—O5	1.400 (4)
Na1—O1^vi	2.444 (3)	B2—O8	1.324 (3)
Na1—O10^vii	2.462 (4)	B2—O9	1.402 (3)
Na1—O3^viii	2.469 (3)	B3—O2	1.312 (4)
Na1—O6^vi	2.723 (4)	B3—O6	1.376 (4)
Na2—O6	2.334 (4)	B3—O7	1.431 (3)
Na2—O9^ix	2.429 (3)	B4—O1	1.391 (4)
Na2—O10^i	2.438 (3)	B4—O3	1.331 (3)
Na2—O3^ix	2.569 (4)	B4—O9	1.392 (3)
Na2—O9^x	2.575 (4)	B5—O4	1.380 (4)
Na2—O2	2.717 (4)	B5—O7	1.416 (4)
Na2—O3^x	3.011 (4)	B5—O10	1.328 (3)
Na3—O2^i	2.266 (3)
O8^i—Sr1—O2^ii	84.49 (10)	O6—Na2—O9^x	152.35 (9)
O8^i—Sr1—O1^iii	131.63 (9)	O9^ix—Na2—O9^x	99.67 (11)
O2^ii—Sr1—O1^iii	83.33 (11)	O10^i—Na2—O9^x	87.80 (11)
O8^i—Sr1—O7	121.08 (9)	O3^ix—Na2—O9^x	85.81 (11)
O2^ii—Sr1—O7	82.80 (10)	O6—Na2—O2	55.06 (10)
O1^iii—Sr1—O7	103.48 (12)	O9^ix—Na2—O2	125.56 (10)
O8^i—Sr1—O3^iv	87.96 (10)	O10^i—Na2—O2	99.96 (11)
O2^ii—Sr1—O3^iv	156.21 (7)	O3^ix—Na2—O2	173.25 (8)
O1^iii—Sr1—O3^iv	84.96 (12)	O9^x—Na2—O2	100.06 (12)
O7—Sr1—O3^iv	120.15 (9)	O6—Na2—O3^x	107.99 (11)
O8^i—Sr1—O3^iii	79.24 (10)	O9^ix—Na2—O3^x	79.35 (10)
O2^ii—Sr1—O3^iii	86.95 (11)	O10^i—Na2—O3^x	133.76 (10)
O1^iii—Sr1—O3^iii	53.53 (10)	O3^ix—Na2—O3^x	109.79 (10)
O7—Sr1—O3^iii	155.93 (6)	O9^x—Na2—O3^x	48.91 (8)
O3^iv—Sr1—O3^iii	69.47 (11)	O2—Na2—O3^x	76.78 (10)
O8^i—Sr1—O10	140.33 (7)	O2^i—Na3—O4^vii	102.28 (11)
O2^ii—Sr1—O10	126.88 (8)	O2^i—Na3—O5	112.84 (11)
O1^iii—Sr1—O10	81.02 (11)	O4^vii—Na3—O5	135.23 (10)
O7—Sr1—O10	52.81 (8)	O2^i—Na3—O10^vii	145.97 (10)
O3^iv—Sr1—O10	71.16 (9)	O4^vii—Na3—O10^vii	56.90 (10)
O3^iii—Sr1—O10	120.92 (9)	O5—Na3—O10^vii	99.54 (10)
O8^i—Sr1—O5^i	52.70 (9)	O2^i—Na3—O4	93.76 (12)
O2^ii—Sr1—O5^i	104.55 (11)	O4^vii—Na3—O4	97.60 (12)
O1^iii—Sr1—O5^i	171.81 (6)	O5—Na3—O4	54.64 (10)
O7—Sr1—O5^i	75.75 (12)	O10^vii—Na3—O4	114.14 (10)
O3^iv—Sr1—O5^i	88.42 (12)	O2^i—Na3—O7^vi	74.94 (11)
O3^iii—Sr1—O5^i	128.08 (10)	O4^vii—Na3—O7^vi	86.36 (12)
O10—Sr1—O5^i	92.29 (11)	O5—Na3—O7^vi	128.23 (10)
O8—Na1—O8^v	91.76 (11)	O10^vii—Na3—O7^vi	76.97 (10)
O8—Na1—O1^vi	150.64 (8)	O4—Na3—O7^vi	168.61 (8)
O8^v—Na1—O1^vi	89.45 (11)	O4—B1—O6	112.1 (2)
O8—Na1—O10^vii	96.99 (11)	O4—B1—O5	108.4 (2)
O8^v—Na1—O10^vii	165.23 (9)	O6—B1—O5	108.65 (18)
O1^vi—Na1—O10^vii	88.73 (11)	O4—B1—O1	109.57 (18)
O8—Na1—O3^viii	117.29 (10)	O6—B1—O1	108.2 (2)
O8^v—Na1—O3^viii	87.18 (12)	O5—B1—O1	109.9 (2)
O1^vi—Na1—O3^viii	92.07 (11)	O8—B2—O5	119.2 (2)
O10^vii—Na1—O3^viii	78.24 (11)	O8—B2—O9	122.8 (3)
O8—Na1—O6^vi	95.81 (11)	O5—B2—O9	118.0 (2)
O8^v—Na1—O6^vi	93.54 (12)	O2—B3—O6	122.7 (2)
O1^vi—Na1—O6^vi	54.84 (9)	O2—B3—O7	121.9 (3)
O10^vii—Na1—O6^vi	97.37 (11)	O6—B3—O7	115.4 (2)
O3^viii—Na1—O6^vi	146.87 (9)	O3—B4—O1	121.8 (2)
O6—Na2—O9^ix	88.34 (12)	O3—B4—O9	119.0 (3)
O6—Na2—O10^i	106.88 (11)	O1—B4—O9	118.9 (2)
O9^ix—Na2—O10^i	131.00 (11)	O10—B5—O4	123.8 (3)
O6—Na2—O3^ix	119.90 (12)	O10—B5—O7	119.0 (3)
O9^ix—Na2—O3^ix	55.91 (9)	O4—B5—O7	117.3 (2)
O10^i—Na2—O3^ix	76.77 (11)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+2, −z+1; (iii) −x, −y+2, −z+1; (iv) x, y, z+1; (v) −x+1, −y, −z; (vi) x, y−1, z; (vii) −x, −y+1, −z+1; (viii) −x, −y+1, −z; (ix) −x+1, −y+1, −z; (x) x+1, y, z.