inorganic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

Distrontium lithium beryllium triborate, Sr2LiBeB3O8

aFujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China
*Correspondence e-mail: nye@fjirsm.ac.cn

(Received 28 March 2012; accepted 6 April 2012; online 18 April 2012)

Single crystals of distrontium lithium beryllium triborate, Sr2LiBeB3O8, were obtained by spontaneous nucleation from a high-temperature melt. In the Sr2Li[BeB3O8] structure, [BeB2O7]6− rings, made up from one BeO4 tetra­hedron and two BO3 triangles, are connected to each other by [BO3] triangles to form the smallest repeat unit {[BeB3O8]8−} and then form chains along the b axis. The Sr2+ cations are seven- or eight-­coordinated and Li+ cations are tetra-­coordinated and lie between the chains.

Related literature

Non-linear optical (NLO) applications of borate crystals with trigonal BO3 anions have been discussed by Chen et al. (1999[Chen, C. T., Ye, N., Lin, J., Jiang, J., Zeng, W. R. & Wu, B. C. (1999). Adv. Mater. 11, 1071-1078.]). Among this group of compounds, beryllium borates are reported to exhibit the shortest transmission cut-off wavelength (Li, 1989[Li, R. K. (1989). J. Non-Cryst. Solids, 111, 199-204.]). A review of the geometry of the BO3 group is given by Zobetz (1982[Zobetz, E. (1982). Z. Kristallogr. 160, 81-92.]), and a similar configuration of the [BeB2O7]6− unit is found in LiB3O5 (LBO; Chen et al., 2005[Chen, C. T., Lin, Z. S. & Wang, Z. Z. (2005). Appl. Phys. B, 80, 1-25.]) in which [B3O7]5− rings are present. The structure of the beryllium borate group [BeB2O7]6− is given by Li & Ye (2007[Li, W. & Ye, N. (2007). Acta Cryst. E63, i160.]).

Experimental

Crystal data
  • Sr2LiBeB3O8

  • Mr = 351.62

  • Monoclinic, P 21 /c

  • a = 8.609 (5) Å

  • b = 6.486 (4) Å

  • c = 12.868 (8) Å

  • β = 106.91 (1)°

  • V = 687.4 (7) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 15.53 mm−1

  • T = 293 K

  • 0.20 × 0.12 × 0.10 mm

Data collection
  • Rigaku Mercury2 diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2007[Rigaku (2007). CrystalClear. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.123, Tmax = 0.212

  • 5147 measured reflections

  • 1574 independent reflections

  • 1429 reflections with I > 2σ(I)

  • Rint = 0.038

Refinement
  • R[F2 > 2σ(F2)] = 0.026

  • wR(F2) = 0.060

  • S = 1.05

  • 1574 reflections

  • 137 parameters

  • Δρmax = 0.97 e Å−3

  • Δρmin = −0.81 e Å−3

Data collection: CrystalClear (Rigaku, 2007[Rigaku (2007). CrystalClear. Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg, 2004[Brandenburg, K. (2004). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Supporting information


Comment top

Based on a theoretical study, beryllium borates possess the largest energy gap among all alkaline and alkaline earth borates, and hence the shortest transmission cut-off wavelength (Li, 1989). In addition, borate crystals containing parallelly aligned BO3 anionic groups are considered to be good candidates for NLO applications (Chen et al., 1999). Therefore, beryllium borates are studied intensively with the purpose of searching for novel compounds with potential applications in the UV region. The title compound, Sr2LiBeB3O8, was found from the investigation of the beryllium borate system containing strontium and lithium.

A perspective view of the Sr2LiBeB3O8 structure in the a-c plane is shown in Fig.1. It contains a similar beryllium borate group [BeB2O7]6- which was found in the structure Na2BeB2O5(Li & Ye, 2007) as the basic group in the Sr2LiBeB3O8 structure. In the structure of non-planar six-ring [BeB2O7]6-, the Be atoms are bonded to four O atoms to form distorted BeO4 tetrahedral. The B atoms are coordinated to three O atoms to form planar BO3 triangles and two planar BO3 groups share one common O1 atom, and each of them also shares a different O atom with a BeO4 tetrahedral.(Fig.3) This structure of the basic structural unit, [BeB2O7]6-, is similar to that of [B3O7]5- in LiB3O5 (LBO) (Chen et al., 2005), with a BO4 replaced by BeO4. In the Sr2LiBeB3O8 structure, the [BeB2O7]6- rings are linked each other by a bridging BO3 group(B3 atom) to form the smallest repeat unit {[BeB3O8]8-} (n) one dimensional chains along the b Axis (Fig.2). From the study of LBO, it is known that the [B3O7]5- group can yield large NLO effects and short UV transmission cut-offs, but spatial arrangement of the endless helices of [B3O7](n) chains along the z axis is unfavorable for producing a large birefringence. Therefore, the resulting layer structure of [BeB2O7](n) along the b axis may be a good candidate for DUV NLO applications. Unfortunately, in the case of Sr2LiBeB3O8, the direction of [BeB2O7]6- group along the b axis are completely opposite and, therefore, their contributions to the NLO effect cancel out.

Related literature top

Non-linear optical (NLO) applications of borate crystals with trigonal BO3 anions have been discussed by Chen et al. (1999). Among this group of compounds, beryllium borates are reported to exhibit the shortest transmission cut-off wavelength (Li, 1989). A review of the geometry of the BO3 group is given by Zobetz (1982), and a similar configuration of the [BeB2O7]6- unit is found in LiB3O5 (LBO; Chen et al., 2005) in which [B3O7]5- rings are present. The structure of the beryllium borate group [BeB2O7]6- is given by Li & Ye (2007).

Experimental top

Single crystals of Sr2LiBeB3O8 were grown from a high-temperature solution using SrO-B2O3—Li2CO3 as a flux. This solution was prepared in a platinum crucible after melting of a mixture of SrCO3, BeO, B2O3 and Li2CO3 at the ratio of SrO/BeO/B2O3/Li2CO3=4:2:3:2. The mixture (10 g) was heated in a temperature-programmable electric furnace at 1273 K until the melt became transparent and clear. The homogenized melt solution was then cooled rapidly (323 K/h) to the initial crystallization temperature (1073 K). It was further cooled slowly (276 K/h) to the final crystallization temperature (973 K) and then allowed to cool to room temperature after the furnace was turned off. The flux attached to the crystal was readily dissolved in water.

Computing details top

Data collection: CrystalClear (Rigaku, 2007); cell refinement: CrystalClear (Rigaku, 2007); data reduction: CrystalClear (Rigaku, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The crystal structure of Sr2Li[BeB3O8], viewed along the b axis, and drawn with anisotropic displacement paremeters at the 50% probability level. Sr—O bonds and Li—O bonds were omitted for clarity.
[Figure 2] Fig. 2. The parallel arrangement of the smallest repeat unit {[BeB3O8]8-} (n) along b axis which forms a one-dimensional infinite chain.
[Figure 3] Fig. 3. [BeB2O7]6- building unit in the title compound.
Distrontium lithium beryllium triborate top
Crystal data top
Sr2LiBeB3O8F(000) = 648
Mr = 351.62Dx = 3.397 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 764 reflections
a = 8.609 (5) Åθ = 4.1–27.5°
b = 6.486 (4) ŵ = 15.53 mm1
c = 12.868 (8) ÅT = 293 K
β = 106.91 (1)°Prism, colorless
V = 687.4 (7) Å30.20 × 0.12 × 0.10 mm
Z = 4
Data collection top
Rigaku Mercury2
diffractometer
1574 independent reflections
Radiation source: fine-focus sealed tube1429 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.038
Detector resolution: 13.6612 pixels mm-1θmax = 27.5°, θmin = 2.5°
CCD_Profile_fitting scansh = 119
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2007)
k = 78
Tmin = 0.123, Tmax = 0.212l = 1616
5147 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.026 w = 1/[σ2(Fo2) + (0.0325P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.060(Δ/σ)max < 0.001
S = 1.05Δρmax = 0.97 e Å3
1574 reflectionsΔρmin = 0.81 e Å3
137 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.0525 (14)
Crystal data top
Sr2LiBeB3O8V = 687.4 (7) Å3
Mr = 351.62Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.609 (5) ŵ = 15.53 mm1
b = 6.486 (4) ÅT = 293 K
c = 12.868 (8) Å0.20 × 0.12 × 0.10 mm
β = 106.91 (1)°
Data collection top
Rigaku Mercury2
diffractometer
1574 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2007)
1429 reflections with I > 2σ(I)
Tmin = 0.123, Tmax = 0.212Rint = 0.038
5147 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.026137 parameters
wR(F2) = 0.0600 restraints
S = 1.05Δρmax = 0.97 e Å3
1574 reflectionsΔρmin = 0.81 e Å3
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
xyzUiso*/Ueq
Sr10.35975 (4)0.24425 (5)0.42862 (2)0.00870 (12)
Sr20.96530 (4)0.89027 (5)0.34184 (2)0.01077 (12)
B10.7378 (5)0.2697 (6)0.4861 (3)0.0081 (7)
B20.9374 (5)0.3471 (6)0.3805 (3)0.0086 (7)
B30.4005 (5)0.4529 (6)0.2060 (3)0.0089 (7)
Be10.6756 (5)0.5709 (7)0.3439 (3)0.0087 (9)
Li10.3681 (9)0.7734 (10)0.3261 (5)0.0212 (15)
O10.8842 (3)0.2319 (4)0.4584 (2)0.0115 (5)
O20.6391 (3)0.4284 (4)0.43886 (18)0.0108 (5)
O30.7074 (3)0.1423 (4)0.56005 (19)0.0135 (5)
O40.8589 (3)0.5215 (4)0.3371 (2)0.0143 (5)
O51.0594 (3)0.2620 (4)0.3497 (2)0.0118 (5)
O60.5555 (3)0.5273 (4)0.22195 (18)0.0105 (5)
O70.6566 (3)0.8100 (4)0.37736 (19)0.0132 (5)
O80.3055 (3)0.5106 (4)0.26900 (19)0.0114 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Sr10.01050 (19)0.0059 (2)0.01079 (19)0.00014 (11)0.00487 (13)0.00049 (11)
Sr20.01267 (19)0.00595 (19)0.01254 (19)0.00039 (12)0.00184 (13)0.00046 (12)
B10.0104 (19)0.0045 (19)0.0099 (18)0.0021 (14)0.0039 (14)0.0027 (14)
B20.0091 (18)0.008 (2)0.0102 (17)0.0036 (14)0.0042 (14)0.0019 (15)
B30.0151 (19)0.0043 (19)0.0073 (17)0.0016 (15)0.0032 (14)0.0022 (14)
Be10.012 (2)0.005 (2)0.010 (2)0.0002 (16)0.0055 (16)0.0020 (16)
Li10.039 (4)0.010 (4)0.021 (3)0.007 (3)0.019 (3)0.005 (3)
O10.0113 (13)0.0102 (14)0.0147 (12)0.0034 (9)0.0063 (9)0.0045 (10)
O20.0117 (12)0.0087 (13)0.0136 (12)0.0004 (9)0.0062 (9)0.0027 (10)
O30.0227 (14)0.0057 (13)0.0154 (12)0.0011 (10)0.0109 (10)0.0022 (10)
O40.0122 (13)0.0085 (13)0.0248 (13)0.0011 (10)0.0093 (10)0.0070 (11)
O50.0127 (13)0.0097 (14)0.0148 (12)0.0001 (9)0.0069 (10)0.0013 (10)
O60.0123 (12)0.0091 (13)0.0112 (12)0.0013 (9)0.0050 (9)0.0012 (10)
O70.0253 (14)0.0039 (13)0.0091 (11)0.0031 (10)0.0029 (10)0.0009 (10)
O80.0126 (12)0.0103 (14)0.0125 (12)0.0018 (10)0.0054 (9)0.0019 (10)
Geometric parameters (Å, º) top
Sr1—O5i2.491 (3)B1—O31.342 (4)
Sr1—O7ii2.565 (3)B1—O21.360 (5)
Sr1—O3iii2.586 (3)B1—O11.428 (5)
Sr1—O82.620 (3)B2—O51.344 (4)
Sr1—O22.654 (3)B2—O41.352 (5)
Sr1—O6iv2.663 (3)B2—O11.428 (4)
Sr1—O2ii2.722 (3)B3—O81.361 (5)
Sr1—O33.051 (3)B3—O61.377 (5)
Sr2—O8v2.478 (3)B3—O7iv1.395 (5)
Sr2—O5vi2.536 (3)Be1—O71.630 (5)
Sr2—O5vii2.551 (3)Be1—O61.634 (5)
Sr2—O42.556 (3)Be1—O21.634 (5)
Sr2—O1viii2.642 (3)Be1—O41.638 (5)
Sr2—O3viii2.740 (3)Li1—O3ii1.849 (7)
Sr2—O72.872 (3)Li1—O81.872 (7)
Sr2—O1vi2.873 (3)Li1—O6v1.940 (7)
Sr2—O4vii3.217 (3)Li1—O72.389 (8)
O5i—Sr1—O7ii93.38 (9)O8v—Sr2—O752.40 (8)
O5i—Sr1—O3iii81.09 (8)O5vi—Sr2—O7117.75 (8)
O7ii—Sr1—O3iii74.69 (8)O5vii—Sr2—O7105.89 (8)
O5i—Sr1—O873.89 (8)O4—Sr2—O759.49 (8)
O7ii—Sr1—O8143.67 (8)O1viii—Sr2—O790.30 (8)
O3iii—Sr1—O8133.75 (8)O3viii—Sr2—O7141.98 (7)
O5i—Sr1—O2144.86 (8)O8v—Sr2—O1vi74.15 (8)
O7ii—Sr1—O2108.59 (8)O5vi—Sr2—O1vi50.90 (8)
O3iii—Sr1—O2130.36 (8)O5vii—Sr2—O1vi142.30 (8)
O8—Sr1—O272.22 (8)O4—Sr2—O1vi126.47 (8)
O5i—Sr1—O6iv101.50 (8)O1viii—Sr2—O1vi81.27 (9)
O7ii—Sr1—O6iv137.73 (9)O3viii—Sr2—O1vi101.09 (8)
O3iii—Sr1—O6iv69.01 (8)O7—Sr2—O1vi71.36 (8)
O8—Sr1—O6iv78.59 (9)O8v—Sr2—O4vii93.68 (8)
O2—Sr1—O6iv80.66 (8)O5vi—Sr2—O4vii64.26 (7)
O5i—Sr1—O2ii91.93 (8)O5vii—Sr2—O4vii47.06 (8)
O7ii—Sr1—O2ii59.23 (8)O4—Sr2—O4vii118.07 (7)
O3iii—Sr1—O2ii132.93 (8)O1viii—Sr2—O4vii125.21 (8)
O8—Sr1—O2ii86.79 (9)O3viii—Sr2—O4vii73.47 (8)
O2—Sr1—O2ii77.27 (8)O7—Sr2—O4vii144.26 (7)
O6iv—Sr1—O2ii156.42 (7)O1vi—Sr2—O4vii113.95 (7)
O5i—Sr1—O3166.09 (8)O3—B1—O2123.9 (3)
O7ii—Sr1—O375.73 (8)O3—B1—O1116.1 (3)
O3iii—Sr1—O387.60 (8)O2—B1—O1120.0 (3)
O8—Sr1—O3120.00 (7)O5—B2—O4124.2 (3)
O2—Sr1—O348.81 (8)O5—B2—O1115.4 (3)
O6iv—Sr1—O381.75 (7)O4—B2—O1120.2 (3)
O2ii—Sr1—O389.86 (7)O8—B3—O6122.7 (3)
O8v—Sr2—O5vi87.68 (9)O8—B3—O7iv120.2 (3)
O8v—Sr2—O5vii75.33 (8)O6—B3—O7iv117.2 (3)
O5vi—Sr2—O5vii106.52 (6)O7—Be1—O6109.5 (3)
O8v—Sr2—O490.61 (9)O7—Be1—O2106.6 (3)
O5vi—Sr2—O4177.22 (8)O6—Be1—O2114.5 (3)
O5vii—Sr2—O475.13 (8)O7—Be1—O4111.9 (3)
O8v—Sr2—O1viii140.12 (7)O6—Be1—O4105.4 (3)
O5vi—Sr2—O1viii100.72 (8)O2—Be1—O4109.1 (3)
O5vii—Sr2—O1viii136.21 (8)O3ii—Li1—O8116.9 (3)
O4—Sr2—O1viii79.23 (8)O3ii—Li1—O6v103.4 (3)
O8v—Sr2—O3viii163.40 (8)O8—Li1—O6v137.1 (4)
O5vi—Sr2—O3viii77.37 (8)O3ii—Li1—O7109.2 (3)
O5vii—Sr2—O3viii101.86 (8)O8—Li1—O7110.9 (3)
O4—Sr2—O3viii104.60 (8)O6v—Li1—O765.3 (2)
O1viii—Sr2—O3viii51.76 (7)
Symmetry codes: (i) x1, y, z; (ii) x+1, y+1, z+1; (iii) x+1, y, z+1; (iv) x+1, y1/2, z+1/2; (v) x+1, y+1/2, z+1/2; (vi) x, y+1, z; (vii) x+2, y+1/2, z+1/2; (viii) x+2, y+1, z+1.

Experimental details

Crystal data
Chemical formulaSr2LiBeB3O8
Mr351.62
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)8.609 (5), 6.486 (4), 12.868 (8)
β (°) 106.91 (1)
V3)687.4 (7)
Z4
Radiation typeMo Kα
µ (mm1)15.53
Crystal size (mm)0.20 × 0.12 × 0.10
Data collection
DiffractometerRigaku Mercury2
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2007)
Tmin, Tmax0.123, 0.212
No. of measured, independent and
observed [I > 2σ(I)] reflections
5147, 1574, 1429
Rint0.038
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.026, 0.060, 1.05
No. of reflections1574
No. of parameters137
Δρmax, Δρmin (e Å3)0.97, 0.81

Computer programs: CrystalClear (Rigaku, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2004), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Nos. 50872132 and 90922035) and the Fujian High Technology Research and Development Program of China (No. 2010H0021).

References

First citationBrandenburg, K. (2004). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationChen, C. T., Lin, Z. S. & Wang, Z. Z. (2005). Appl. Phys. B, 80, 1–25.  Web of Science CrossRef CAS Google Scholar
First citationChen, C. T., Ye, N., Lin, J., Jiang, J., Zeng, W. R. & Wu, B. C. (1999). Adv. Mater. 11, 1071–1078.  Web of Science CrossRef CAS Google Scholar
First citationLi, R. K. (1989). J. Non-Cryst. Solids, 111, 199–204.  Google Scholar
First citationLi, W. & Ye, N. (2007). Acta Cryst. E63, i160.  Web of Science CrossRef IUCr Journals Google Scholar
First citationRigaku (2007). CrystalClear. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationZobetz, E. (1982). Z. Kristallogr. 160, 81–92.  CrossRef CAS Web of Science Google Scholar

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