Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807028942/wm2126sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807028942/wm2126Isup2.hkl |
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (O-B) = 0.001 Å
- R factor = 0.022
- wR factor = 0.059
- Data-to-parameter ratio = 10.2
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 1.11
Alert level G ABSTM02_ALERT_3_G When printed, the submitted absorption T values will be replaced by the scaled T values. Since the ratio of scaled T's is identical to the ratio of reported T values, the scaling does not imply a change to the absorption corrections used in the study. Ratio of Tmax expected/reported 1.109 Tmax scaled 0.981 Tmin scaled 0.961 PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature . 293 K
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 3 ALERT level G = General alerts; check 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
Nonlinear 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), where [B3O7]5- rings are present.
Single crystals of compound (I) were grown using a Na4B2O5 flux. The composition of the mixture for crystal growth was 2:1:3 of Na2CO3 (Hongguang Materials, 99.8%), BeO (Shuikoushan Materials, 99.8%), and H3BO3 (Jinghua Materials, 95%). This mixture was heated in a Pt crucible to 1073 K, held at this temperature for several hours, and then cooled at a rate of 3 K h-1 from 1073 to 873 K. The remaining solified flux attached to the crystals was readily dissolved in water. Crystals with an average size of 0.5 mm and mostly block-shaped habit were obtained.
Borate crystals containing parallell aligned BO3 anions are predicted to have large nonlinear optical (NLO) coefficients, moderate birefringence and wide transparency in the UV region. Therefore they are considered to be good candidates for NLO applications (Chen et al., 1999). 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). Therefore, beryllium borates are studied intensively with the purpose of searching for new NLO materials in the UV region. The title compound, Na2[BeB2O5], (I), was found from the investigation of the pseudo-ternary system Na2O-BeO-B2O3.
A perspective view of the structure of (I) along the a direction is shown in Fig.1. The Be atoms are bonded to four O atoms to form slightly distorted BeO4 tetrahedra (site symmetry. 2). The Be—O bonds can be classified into two groups with different bond lengths of 1.6391 (14) Å for Be—O1 and 1.6584 (14) Å for Be—O2. The O—Be—O angles vary from 107.07 (12) to 111.37 (4)°, indicating a slight distortion from the ideal tetrahedron. The B atoms are coordinated to three O atoms to form planar BO3 triangles with a mean B—O bond length of 1.378 Å (Table 1) and O—B—O angles ranging from 116.70 (11) to 123.15 (11)°, which is in good agreement with the results of geometric studies for the triangular BO3 group (Zobetz, 1982). Two BO3 groups, slightly tilted against each other, share one O3 atom, and each of them also share a different O1 atom with a BeO4 tetrahedron to form a six-membered [BeB2O7]6- ring (Fig. 2). These [BeB2O7]6- rings are further condensed, resulting in a [BeB2O5]∞2- layer parallel to the ab plane. Between adjacent [BeB2O5]∞2- layers the Na+ cations are located in a [6 + 1] coordination, with one considerably longer Na—O bond of 2.8197 (10) Å (Table 1).
The conformation of the [BeB2O7]6- rings is similar to that of the [B3O7]5- units in LiB3O5 (LBO) (Chen et al., 2005), with the BO4 tetrahedron replaced by a BeO4 tetrahedron. 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 the spatial arrangement of the helical [B3O5]∞ chains along the c axis is unfavorable for the generation of a large birefringence. Therefore, compounds with a [BeB2O5]∞ layer structure may be good candidates for deep UV NLO applications. Unfortunately, in the case of (I), the direction of the [BeB2O7]6- groups in the two adjacent layers are completely opposite, and thus their contributions to the NLO effect are eliminated.
Nonlinear 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), where [B3O7]5- rings are present.
Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: enCIFer (Allen et al., 2004).
Na2[BeB2O5] | F(000) = 304 |
Mr = 156.61 | Dx = 2.475 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 616 reflections |
a = 5.8117 (5) Å | θ = 2.3–27.5° |
b = 8.1666 (7) Å | µ = 0.39 mm−1 |
c = 8.9830 (8) Å | T = 293 K |
β = 99.665 (14)° | Prism, colourless |
V = 420.30 (7) Å3 | 0.12 × 0.10 × 0.05 mm |
Z = 4 |
Rigaku Mercury CCD diffractometer | 489 independent reflections |
Radiation source: Sealed Tube | 450 reflections with I > 2σ(I) |
Graphite Monochromator monochromator | Rint = 0.014 |
Detector resolution: 14.6306 pixels mm-1 | θmax = 27.5°, θmin = 4.4° |
CCD_Profile_fitting scans | h = −7→7 |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2000) | k = −9→10 |
Tmin = 0.866, Tmax = 0.884 | l = −10→11 |
1621 measured reflections |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
R[F2 > 2σ(F2)] = 0.022 | Secondary atom site location: difference Fourier map |
wR(F2) = 0.059 | w = 1/[σ2(Fo2) + (0.0287P)2 + 0.2765P] where P = (Fo2 + 2Fc2)/3 |
S = 1.17 | (Δ/σ)max < 0.001 |
489 reflections | Δρmax = 0.22 e Å−3 |
48 parameters | Δρmin = −0.18 e Å−3 |
Na2[BeB2O5] | V = 420.30 (7) Å3 |
Mr = 156.61 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 5.8117 (5) Å | µ = 0.39 mm−1 |
b = 8.1666 (7) Å | T = 293 K |
c = 8.9830 (8) Å | 0.12 × 0.10 × 0.05 mm |
β = 99.665 (14)° |
Rigaku Mercury CCD diffractometer | 489 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2000) | 450 reflections with I > 2σ(I) |
Tmin = 0.866, Tmax = 0.884 | Rint = 0.014 |
1621 measured reflections |
R[F2 > 2σ(F2)] = 0.022 | 48 parameters |
wR(F2) = 0.059 | 0 restraints |
S = 1.17 | Δρmax = 0.22 e Å−3 |
489 reflections | Δρmin = −0.18 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | ||
Na | −0.01389 (8) | 0.30641 (6) | 0.42612 (6) | 0.0142 (2) | |
O1 | −0.34432 (14) | 0.32884 (10) | 0.15850 (10) | 0.0113 (2) | |
O2 | 0.16865 (14) | 0.58926 (10) | 0.37065 (10) | 0.0108 (2) | |
O3 | 0 | 0.07376 (14) | 0.25 | 0.0140 (3) | |
B | −0.3344 (2) | 0.49318 (16) | 0.17748 (15) | 0.0087 (3) | |
Be | −0.5 | 0.2100 (2) | 0.25 | 0.0087 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Na | 0.0145 (3) | 0.0145 (3) | 0.0150 (3) | −0.00079 (18) | 0.0065 (2) | −0.00110 (18) |
O1 | 0.0127 (4) | 0.0078 (4) | 0.0154 (4) | −0.0005 (3) | 0.0082 (3) | −0.0002 (3) |
O2 | 0.0109 (4) | 0.0099 (4) | 0.0124 (4) | 0.0028 (3) | 0.0046 (3) | 0.0008 (3) |
O3 | 0.0135 (6) | 0.0073 (6) | 0.0243 (7) | 0 | 0.0120 (5) | 0 |
B | 0.0074 (6) | 0.0097 (6) | 0.0087 (6) | 0.0003 (4) | 0.0008 (5) | 0.0010 (5) |
Be | 0.0090 (9) | 0.0064 (9) | 0.0115 (10) | 0 | 0.0043 (8) | 0 |
Na—O2i | 2.3279 (10) | O2—Nai | 2.3279 (10) |
Na—O1ii | 2.3402 (9) | O2—Naviii | 2.5473 (9) |
Na—O1iii | 2.4203 (10) | O3—Bv | 1.4123 (14) |
Na—O3 | 2.4824 (10) | O3—Bix | 1.4123 (14) |
Na—O2iv | 2.5473 (9) | O3—Naii | 2.4824 (10) |
Na—O2 | 2.6243 (9) | B—O1 | 1.3529 (15) |
Na—Bv | 2.8128 (14) | B—O2ii | 1.3675 (15) |
Na—Bii | 2.8145 (14) | B—O3x | 1.4123 (14) |
Na—O1 | 2.8197 (10) | B—Naxi | 2.8128 (14) |
Na—Bevi | 2.9000 (6) | B—Naii | 2.8145 (14) |
Na—B | 3.0639 (13) | Be—O1xii | 1.6391 (14) |
Na—Be | 3.0991 (7) | Be—O2v | 1.6584 (14) |
O1—Be | 1.6391 (14) | Be—O2iv | 1.6584 (14) |
O1—Naii | 2.3402 (9) | Be—Navi | 2.9000 (6) |
O1—Navii | 2.4203 (10) | Be—Navii | 2.9000 (6) |
O2—Bii | 1.3675 (15) | Be—Naxii | 3.0991 (7) |
O2—Beviii | 1.6584 (14) | ||
O2i—Na—O1ii | 135.07 (4) | Be—O1—Na | 83.58 (4) |
O2i—Na—O1iii | 69.25 (3) | Naii—O1—Na | 75.89 (3) |
O1ii—Na—O1iii | 93.45 (3) | Navii—O1—Na | 145.70 (4) |
O2i—Na—O3 | 146.94 (3) | Bii—O2—Beviii | 120.32 (8) |
O1ii—Na—O3 | 74.16 (3) | Bii—O2—Nai | 147.49 (8) |
O1iii—Na—O3 | 98.53 (3) | Beviii—O2—Nai | 91.79 (4) |
O2i—Na—O2iv | 92.62 (3) | Bii—O2—Naviii | 86.32 (7) |
O1ii—Na—O2iv | 130.21 (3) | Beviii—O2—Naviii | 92.48 (6) |
O1iii—Na—O2iv | 91.58 (3) | Nai—O2—Naviii | 87.38 (3) |
O3—Na—O2iv | 56.11 (2) | Bii—O2—Na | 83.32 (7) |
O2i—Na—O2 | 92.78 (3) | Beviii—O2—Na | 115.71 (6) |
O1ii—Na—O2 | 57.28 (3) | Nai—O2—Na | 87.22 (3) |
O1iii—Na—O2 | 116.52 (3) | Naviii—O2—Na | 151.43 (4) |
O3—Na—O2 | 119.69 (3) | Bv—O3—Bix | 124.46 (14) |
O2iv—Na—O2 | 151.43 (4) | Bv—O3—Na | 88.00 (6) |
O2i—Na—O1 | 110.32 (3) | Bix—O3—Na | 138.43 (6) |
O1ii—Na—O1 | 103.51 (3) | Bv—O3—Naii | 138.43 (6) |
O1iii—Na—O1 | 152.30 (3) | Bix—O3—Naii | 88.00 (6) |
O3—Na—O1 | 66.22 (2) | Na—O3—Naii | 80.12 (4) |
O2iv—Na—O1 | 60.74 (3) | O1—B—O2ii | 123.15 (11) |
O2—Na—O1 | 91.15 (3) | O1—B—O3x | 120.16 (11) |
B—O1—Be | 122.68 (10) | O2ii—B—O3x | 116.70 (11) |
B—O1—Naii | 95.57 (7) | O1—Be—O1xii | 107.35 (12) |
Be—O1—Naii | 135.44 (7) | O1—Be—O2v | 109.86 (4) |
B—O1—Navii | 124.34 (7) | O1xii—Be—O2v | 111.37 (4) |
Be—O1—Navii | 89.03 (5) | O1—Be—O2iv | 111.37 (4) |
Naii—O1—Navii | 86.55 (3) | O1xii—Be—O2iv | 109.86 (4) |
B—O1—Na | 87.04 (7) | O2v—Be—O2iv | 107.07 (12) |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, y, −z+1/2; (iii) x+1/2, −y+1/2, z+1/2; (iv) x−1/2, y−1/2, z; (v) −x−1/2, y−1/2, −z+1/2; (vi) −x−1/2, −y+1/2, −z+1; (vii) x−1/2, −y+1/2, z−1/2; (viii) x+1/2, y+1/2, z; (ix) x+1/2, y−1/2, z; (x) x−1/2, y+1/2, z; (xi) −x−1/2, y+1/2, −z+1/2; (xii) −x−1, y, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | Na2[BeB2O5] |
Mr | 156.61 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 293 |
a, b, c (Å) | 5.8117 (5), 8.1666 (7), 8.9830 (8) |
β (°) | 99.665 (14) |
V (Å3) | 420.30 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.39 |
Crystal size (mm) | 0.12 × 0.10 × 0.05 |
Data collection | |
Diffractometer | Rigaku Mercury CCD |
Absorption correction | Multi-scan (CrystalClear; Rigaku, 2000) |
Tmin, Tmax | 0.866, 0.884 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1621, 489, 450 |
Rint | 0.014 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.022, 0.059, 1.17 |
No. of reflections | 489 |
No. of parameters | 48 |
Δρmax, Δρmin (e Å−3) | 0.22, −0.18 |
Computer programs: CrystalClear (Rigaku, 2000), CrystalClear, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 2004), enCIFer (Allen et al., 2004).
Na—O2i | 2.3279 (10) | Na—O1 | 2.8197 (10) |
Na—O1ii | 2.3402 (9) | B—O1 | 1.3529 (15) |
Na—O1iii | 2.4203 (10) | B—O2ii | 1.3675 (15) |
Na—O3 | 2.4824 (10) | B—O3v | 1.4123 (14) |
Na—O2iv | 2.5473 (9) | Be—O1vi | 1.6391 (14) |
Na—O2 | 2.6243 (9) | Be—O2vii | 1.6584 (14) |
O1—B—O2ii | 123.15 (11) | O1—Be—O2vii | 109.86 (4) |
O1—B—O3v | 120.16 (11) | O1—Be—O2iv | 111.37 (4) |
O2ii—B—O3v | 116.70 (11) | O2vii—Be—O2iv | 107.07 (12) |
O1—Be—O1vi | 107.35 (12) |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, y, −z+1/2; (iii) x+1/2, −y+1/2, z+1/2; (iv) x−1/2, y−1/2, z; (v) x−1/2, y+1/2, z; (vi) −x−1, y, −z+1/2; (vii) −x−1/2, y−1/2, −z+1/2. |
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Borate crystals containing parallell aligned BO3 anions are predicted to have large nonlinear optical (NLO) coefficients, moderate birefringence and wide transparency in the UV region. Therefore they are considered to be good candidates for NLO applications (Chen et al., 1999). 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). Therefore, beryllium borates are studied intensively with the purpose of searching for new NLO materials in the UV region. The title compound, Na2[BeB2O5], (I), was found from the investigation of the pseudo-ternary system Na2O-BeO-B2O3.
A perspective view of the structure of (I) along the a direction is shown in Fig.1. The Be atoms are bonded to four O atoms to form slightly distorted BeO4 tetrahedra (site symmetry. 2). The Be—O bonds can be classified into two groups with different bond lengths of 1.6391 (14) Å for Be—O1 and 1.6584 (14) Å for Be—O2. The O—Be—O angles vary from 107.07 (12) to 111.37 (4)°, indicating a slight distortion from the ideal tetrahedron. The B atoms are coordinated to three O atoms to form planar BO3 triangles with a mean B—O bond length of 1.378 Å (Table 1) and O—B—O angles ranging from 116.70 (11) to 123.15 (11)°, which is in good agreement with the results of geometric studies for the triangular BO3 group (Zobetz, 1982). Two BO3 groups, slightly tilted against each other, share one O3 atom, and each of them also share a different O1 atom with a BeO4 tetrahedron to form a six-membered [BeB2O7]6- ring (Fig. 2). These [BeB2O7]6- rings are further condensed, resulting in a [BeB2O5]∞2- layer parallel to the ab plane. Between adjacent [BeB2O5]∞2- layers the Na+ cations are located in a [6 + 1] coordination, with one considerably longer Na—O bond of 2.8197 (10) Å (Table 1).
The conformation of the [BeB2O7]6- rings is similar to that of the [B3O7]5- units in LiB3O5 (LBO) (Chen et al., 2005), with the BO4 tetrahedron replaced by a BeO4 tetrahedron. 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 the spatial arrangement of the helical [B3O5]∞ chains along the c axis is unfavorable for the generation of a large birefringence. Therefore, compounds with a [BeB2O5]∞ layer structure may be good candidates for deep UV NLO applications. Unfortunately, in the case of (I), the direction of the [BeB2O7]6- groups in the two adjacent layers are completely opposite, and thus their contributions to the NLO effect are eliminated.