A new compound, dilithium aluminium pentaborate, Li2AlB5O10, has been synthesized by solid-state reaction and its structure determined by single-crystal X-ray diffraction. This compound is composed of [B5O10]5- groups linked by AlO4 tetrahedra. The [B5O10]5- group consists of two hexagonal B-O rings perpendicular to each other connected by tetracoordinated boron. All the B-O rings in this structure can be divided into two groups, with one group approximately parallel and the other perpendicular to the c axis.
Supporting information
A powder mixture of Li2CO3 (0.7388 g, 10 mmol, Beijing Chemical Company,
p.a.), Al2O3 (0.5098 g, 5 mmol, Beijing Chemical Company, p.a.) and
H3BO3 (3.7098 g, 60 mmol, Beijing Chemical Company, p.a.) was melted at
1173 K in a Pt crucible. The melt was kept at 1173 K for 3 h to homogenize and
then cooled to 1123 K at a rate of 10 K h-1 and to 1023 K at 2 K h-1. At
last, the sample was further cooled to 673 K at a rate of 20 K h-1 and then
the power of the furnace was cut off. The crucible was removed from the
furnace after it had been cooled to room temperature. It was found that the
title compound crystallized as transparent irregular grains. The X-ray powder
diffraction pattern of the sample can be indexed with a unit cell that is
given by the single-crystal data and shows some additional very weak
reflections of LiB3O5.
Data collection: SMART (Bruker, 2000); cell refinement: SMART; data reduction: SHELXTL (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1999); software used to prepare material for publication: SHELXL97.
Crystal data top
Li2AlB5O10 | F(000) = 496 |
Mr = 254.91 | Dx = 2.286 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71070 Å |
a = 7.0402 (4) Å | Cell parameters from 7060 reflections |
b = 14.9404 (8) Å | θ = 2.7–33.3° |
c = 7.0433 (4) Å | µ = 0.32 mm−1 |
β = 90.702 (1)° | T = 295 K |
V = 740.78 (7) Å3 | Prism, colorless |
Z = 4 | 0.20 × 0.15 × 0.10 mm |
Data collection top
Bruker Apex CCD area detector diffractometer | 2491 reflections with I > 2s(I) |
Radiation source: sealed tube | Rint = 0.042 |
Graphite monochromator | θmax = 33.3°, θmin = 2.7° |
ϕ and ω scans | h = −10→9 |
6930 measured reflections | k = −23→18 |
2728 independent reflections | l = −10→10 |
Refinement top
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
R[F2 > 2σ(F2)] = 0.034 | Secondary atom site location: difference Fourier map |
wR(F2) = 0.107 | w = 1/[σ2(Fo2) + (0.1P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.87 | (Δ/σ)max < 0.001 |
2728 reflections | Δρmax = 0.48 e Å−3 |
163 parameters | Δρmin = −0.52 e Å−3 |
Crystal data top
Li2AlB5O10 | V = 740.78 (7) Å3 |
Mr = 254.91 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.0402 (4) Å | µ = 0.32 mm−1 |
b = 14.9404 (8) Å | T = 295 K |
c = 7.0433 (4) Å | 0.20 × 0.15 × 0.10 mm |
β = 90.702 (1)° | |
Data collection top
Bruker Apex CCD area detector diffractometer | 2491 reflections with I > 2s(I) |
6930 measured reflections | Rint = 0.042 |
2728 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.034 | 163 parameters |
wR(F2) = 0.107 | 0 restraints |
S = 0.87 | Δρmax = 0.48 e Å−3 |
2728 reflections | Δρmin = −0.52 e Å−3 |
Special details top
Experimental. The title compound crystallized in the monoclinic system; space group
P21/cf.rom the systematic absences. |
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 | x | y | z | Uiso*/Ueq | |
Al1 | 0.14974 (4) | 0.375767 (17) | 0.03729 (4) | 0.00961 (10) | |
B1 | −0.20982 (15) | 0.27914 (7) | −0.02048 (15) | 0.01181 (18) | |
B2 | 0.20154 (14) | 0.47201 (7) | 0.40124 (14) | 0.01128 (18) | |
B3 | 0.24323 (14) | 0.49977 (7) | −0.26461 (14) | 0.01174 (18) | |
B4 | 0.45556 (14) | 0.24680 (7) | 0.00024 (14) | 0.01154 (18) | |
B5 | 0.67924 (15) | 0.12016 (6) | −0.00738 (16) | 0.01230 (19) | |
O1 | −0.07948 (10) | 0.34515 (5) | −0.03203 (10) | 0.01405 (15) | |
O2 | 0.27404 (10) | 0.27577 (5) | 0.01353 (11) | 0.01486 (15) | |
O3 | 0.14951 (11) | 0.40908 (5) | 0.27338 (10) | 0.01409 (15) | |
O4 | 0.24280 (11) | 0.46799 (5) | −0.08301 (10) | 0.01533 (15) | |
O5 | 0.28242 (10) | 0.55170 (4) | 0.35823 (10) | 0.01338 (15) | |
O6 | 0.16369 (10) | 0.44861 (4) | 0.58969 (10) | 0.01250 (14) | |
O7 | 0.49563 (10) | 0.15948 (4) | 0.02629 (11) | 0.01519 (15) | |
O8 | −0.16799 (10) | 0.19115 (5) | 0.00542 (11) | 0.01511 (15) | |
O9 | −0.39874 (10) | 0.30678 (4) | −0.03956 (10) | 0.01498 (15) | |
O10 | 0.31935 (11) | 0.58014 (5) | −0.30375 (10) | 0.01587 (15) | |
Li1 | 0.1033 (3) | 0.17197 (12) | −0.0005 (3) | 0.0190 (3) | |
Li2 | 0.3063 (3) | 0.57076 (13) | 0.0854 (3) | 0.0213 (4) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Al1 | 0.00893 (15) | 0.00830 (15) | 0.01159 (15) | −0.00029 (8) | 0.00032 (10) | −0.00053 (8) |
B1 | 0.0099 (4) | 0.0106 (4) | 0.0149 (4) | 0.0001 (3) | −0.0007 (3) | −0.0001 (3) |
B2 | 0.0113 (4) | 0.0101 (4) | 0.0125 (4) | −0.0009 (3) | 0.0008 (3) | −0.0002 (3) |
B3 | 0.0117 (4) | 0.0107 (4) | 0.0128 (4) | −0.0004 (3) | 0.0006 (3) | −0.0007 (3) |
B4 | 0.0099 (4) | 0.0110 (4) | 0.0137 (4) | 0.0007 (3) | −0.0002 (3) | −0.0011 (3) |
B5 | 0.0119 (4) | 0.0089 (4) | 0.0161 (4) | 0.0015 (3) | 0.0009 (3) | −0.0002 (3) |
O1 | 0.0102 (3) | 0.0116 (3) | 0.0203 (3) | −0.0013 (2) | −0.0015 (2) | 0.0006 (2) |
O2 | 0.0091 (3) | 0.0115 (3) | 0.0240 (3) | 0.0015 (2) | 0.0013 (2) | −0.0018 (2) |
O3 | 0.0175 (3) | 0.0124 (3) | 0.0125 (3) | −0.0030 (2) | 0.0008 (2) | −0.0019 (2) |
O4 | 0.0208 (4) | 0.0131 (3) | 0.0120 (3) | −0.0043 (2) | 0.0001 (2) | 0.0010 (2) |
O5 | 0.0168 (3) | 0.0093 (3) | 0.0141 (3) | −0.0028 (2) | 0.0016 (2) | 0.0003 (2) |
O6 | 0.0152 (3) | 0.0107 (3) | 0.0116 (3) | −0.0025 (2) | 0.0006 (2) | −0.0001 (2) |
O7 | 0.0103 (3) | 0.0095 (3) | 0.0258 (4) | 0.0009 (2) | 0.0026 (3) | 0.0002 (2) |
O8 | 0.0108 (3) | 0.0094 (3) | 0.0252 (3) | 0.0007 (2) | 0.0010 (3) | 0.0011 (2) |
O9 | 0.0098 (3) | 0.0105 (3) | 0.0247 (4) | 0.0002 (2) | −0.0006 (2) | 0.0021 (2) |
O10 | 0.0214 (4) | 0.0117 (3) | 0.0145 (3) | −0.0055 (2) | −0.0009 (3) | 0.0003 (2) |
Li1 | 0.0167 (9) | 0.0126 (7) | 0.0277 (9) | −0.0002 (6) | −0.0009 (7) | −0.0015 (7) |
Li2 | 0.0293 (10) | 0.0143 (8) | 0.0204 (9) | −0.0019 (7) | −0.0010 (7) | 0.0007 (7) |
Geometric parameters (Å, º) top
Al1—O3 | 1.7357 (7) | B5—O7 | 1.4421 (12) |
Al1—O2 | 1.7405 (7) | B5—O10v | 1.4586 (13) |
Al1—O1 | 1.7414 (7) | B5—O5vi | 1.4885 (12) |
Al1—O4 | 1.7491 (7) | B5—O8iv | 1.5124 (12) |
Al1—Li1 | 3.0735 (19) | Li2—O1i | 2.063 (2) |
Al1—Li2 | 3.132 (2) | Li1—O2 | 1.964 (2) |
B1—O1 | 1.3502 (12) | O3—Li1ii | 2.030 (2) |
B1—O8 | 1.3591 (12) | Li2—O4 | 1.988 (2) |
B1—O9 | 1.3976 (12) | O5—B5vii | 1.4885 (12) |
B1—Li2i | 2.386 (2) | Li2—O5 | 1.952 (2) |
B1—Li1 | 2.727 (2) | O6—B3viii | 1.3917 (12) |
B2—O3 | 1.3495 (11) | O6—Li1ii | 1.955 (2) |
B2—O5 | 1.3556 (12) | O8—B5ix | 1.5124 (12) |
B2—O6 | 1.4013 (12) | Li1—O8 | 1.932 (2) |
B2—Li1ii | 2.366 (2) | O9—B4ix | 1.3931 (12) |
B2—Li2 | 2.776 (2) | O9—Li2i | 1.970 (2) |
B3—O10 | 1.3447 (12) | O10—B5x | 1.4586 (13) |
B3—O4 | 1.3644 (12) | Li1—O6xi | 1.955 (2) |
B3—O6iii | 1.3917 (12) | Li1—O3xi | 2.030 (2) |
B3—Li2 | 2.715 (2) | Li1—B2xi | 2.366 (2) |
B4—O7 | 1.3469 (12) | Li2—O9i | 1.970 (2) |
B4—O2 | 1.3536 (12) | Li2—O1i | 2.063 (2) |
B4—O9iv | 1.3931 (12) | Li2—B1i | 2.386 (2) |
B4—Li1 | 2.720 (2) | | |
| | | |
O3—Al1—O2 | 110.16 (4) | B3viii—O6—B2 | 118.81 (7) |
O3—Al1—O1 | 109.40 (4) | B3viii—O6—Li1ii | 146.06 (8) |
O2—Al1—O1 | 102.29 (4) | B2—O6—Li1ii | 88.00 (8) |
O3—Al1—O4 | 104.06 (3) | B4—O7—B5 | 123.97 (8) |
O2—Al1—O4 | 115.96 (4) | B1—O8—B5ix | 121.17 (8) |
O1—Al1—O4 | 114.99 (4) | B1—O8—Li1 | 110.68 (8) |
O3—Al1—Li1 | 111.45 (5) | B5ix—O8—Li1 | 126.66 (8) |
O2—Al1—Li1 | 36.33 (4) | B4ix—O9—B1 | 119.52 (7) |
O1—Al1—Li1 | 67.56 (4) | B4ix—O9—Li2i | 151.17 (9) |
O4—Al1—Li1 | 141.12 (5) | B1—O9—Li2i | 88.52 (8) |
O3—Al1—Li2 | 68.53 (4) | B3—O10—B5x | 124.07 (8) |
O2—Al1—Li2 | 129.22 (5) | O8—Li1—O6xi | 109.91 (10) |
O1—Al1—Li2 | 126.75 (5) | O8—Li1—O2 | 119.10 (10) |
O4—Al1—Li2 | 35.53 (4) | O6xi—Li1—O2 | 125.50 (10) |
Li1—Al1—Li2 | 165.44 (5) | O8—Li1—O3xi | 105.87 (9) |
O1—B1—O8 | 124.63 (9) | O6xi—Li1—O3xi | 70.67 (7) |
O1—B1—O9 | 115.16 (8) | O2—Li1—O3xi | 114.00 (10) |
O8—B1—O9 | 120.21 (9) | O8—Li1—B2xi | 115.71 (9) |
O1—B1—Li2i | 59.60 (7) | O6xi—Li1—B2xi | 36.30 (4) |
O8—B1—Li2i | 174.70 (9) | O2—Li1—B2xi | 123.50 (10) |
O9—B1—Li2i | 55.64 (7) | O3xi—Li1—B2xi | 34.70 (4) |
O1—B1—Li1 | 83.24 (7) | O8—Li1—B1 | 27.79 (4) |
O8—B1—Li1 | 41.53 (6) | O6xi—Li1—B1 | 136.90 (10) |
O9—B1—Li1 | 161.13 (8) | O2—Li1—B1 | 91.88 (7) |
Li2i—B1—Li1 | 142.17 (8) | O3xi—Li1—B1 | 116.56 (9) |
O3—B2—O5 | 125.04 (9) | B2xi—Li1—B1 | 139.28 (9) |
O3—B2—O6 | 113.89 (8) | O8—Li1—B4 | 147.18 (10) |
O5—B2—O6 | 121.07 (8) | O6xi—Li1—B4 | 100.57 (8) |
O3—B2—Li1ii | 58.91 (7) | O2—Li1—B4 | 28.11 (4) |
O5—B2—Li1ii | 171.53 (9) | O3xi—Li1—B4 | 95.27 (8) |
O6—B2—Li1ii | 55.70 (6) | B2xi—Li1—B4 | 96.00 (7) |
O3—B2—Li2 | 84.73 (7) | B1—Li1—B4 | 119.68 (7) |
O5—B2—Li2 | 40.35 (6) | O8—Li1—Al1 | 87.44 (7) |
O6—B2—Li2 | 161.25 (8) | O6xi—Li1—Al1 | 149.55 (9) |
Li1ii—B2—Li2 | 143.03 (8) | O2—Li1—Al1 | 31.67 (4) |
O10—B3—O4 | 120.56 (8) | O3xi—Li1—Al1 | 129.87 (9) |
O10—B3—O6iii | 119.80 (8) | B2xi—Li1—Al1 | 153.51 (9) |
O4—B3—O6iii | 119.64 (8) | B1—Li1—Al1 | 60.52 (4) |
O10—B3—Li2 | 77.07 (7) | B4—Li1—Al1 | 59.78 (4) |
O4—B3—Li2 | 44.52 (6) | O5—Li2—O9i | 109.24 (10) |
O6iii—B3—Li2 | 160.70 (8) | O5—Li2—O4 | 116.96 (10) |
O7—B4—O2 | 119.78 (9) | O9i—Li2—O4 | 133.78 (11) |
O7—B4—O9iv | 119.80 (8) | O5—Li2—O1i | 101.10 (10) |
O2—B4—O9iv | 120.42 (8) | O9i—Li2—O1i | 70.19 (7) |
O7—B4—Li1 | 77.97 (7) | O4—Li2—O1i | 101.18 (9) |
O2—B4—Li1 | 43.12 (6) | O5—Li2—B1i | 107.35 (9) |
O9iv—B4—Li1 | 159.62 (8) | O9i—Li2—B1i | 35.85 (5) |
O7—B5—O10v | 109.46 (8) | O4—Li2—B1i | 123.39 (10) |
O7—B5—O5vi | 108.60 (8) | O1i—Li2—B1i | 34.37 (4) |
O10v—B5—O5vi | 111.03 (7) | O5—Li2—B3 | 145.27 (10) |
O7—B5—O8iv | 110.04 (7) | O9i—Li2—B3 | 105.34 (8) |
O10v—B5—O8iv | 109.21 (8) | O4—Li2—B3 | 28.77 (4) |
O5vi—B5—O8iv | 108.49 (8) | O1i—Li2—B3 | 87.41 (7) |
B1—O1—Al1 | 143.43 (6) | B1i—Li2—B3 | 98.64 (8) |
B1—O1—Li2i | 86.03 (8) | O5—Li2—B2 | 26.72 (4) |
Al1—O1—Li2i | 127.13 (7) | O9i—Li2—B2 | 135.76 (10) |
B4—O2—Al1 | 139.23 (7) | O4—Li2—B2 | 90.44 (7) |
B4—O2—Li1 | 108.77 (8) | O1i—Li2—B2 | 104.90 (9) |
Al1—O2—Li1 | 111.99 (7) | B1i—Li2—B2 | 125.12 (9) |
B2—O3—Al1 | 146.68 (7) | B3—Li2—B2 | 118.55 (8) |
B2—O3—Li1ii | 86.39 (8) | O5—Li2—Al1 | 86.36 (7) |
Al1—O3—Li1ii | 125.63 (7) | O9i—Li2—Al1 | 164.32 (9) |
B3—O4—Al1 | 137.18 (6) | O4—Li2—Al1 | 30.75 (4) |
B3—O4—Li2 | 106.71 (8) | O1i—Li2—Al1 | 106.04 (8) |
Al1—O4—Li2 | 113.72 (7) | B1i—Li2—Al1 | 139.00 (9) |
B2—O5—B5vii | 121.25 (8) | B3—Li2—Al1 | 59.00 (4) |
B2—O5—Li2 | 112.93 (8) | B2—Li2—Al1 | 59.73 (4) |
B5vii—O5—Li2 | 125.28 (8) | | |
Symmetry codes: (i) −x, −y+1, −z; (ii) x, −y+1/2, z+1/2; (iii) x, y, z−1; (iv) x+1, y, z; (v) −x+1, y−1/2, −z−1/2; (vi) −x+1, y−1/2, −z+1/2; (vii) −x+1, y+1/2, −z+1/2; (viii) x, y, z+1; (ix) x−1, y, z; (x) −x+1, y+1/2, −z−1/2; (xi) x, −y+1/2, z−1/2. |
Experimental details
Crystal data |
Chemical formula | Li2AlB5O10 |
Mr | 254.91 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 295 |
a, b, c (Å) | 7.0402 (4), 14.9404 (8), 7.0433 (4) |
β (°) | 90.702 (1) |
V (Å3) | 740.78 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.32 |
Crystal size (mm) | 0.20 × 0.15 × 0.10 |
|
Data collection |
Diffractometer | Bruker Apex CCD area detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2s(I)] reflections | 6930, 2728, 2491 |
Rint | 0.042 |
(sin θ/λ)max (Å−1) | 0.773 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.107, 0.87 |
No. of reflections | 2728 |
No. of parameters | 163 |
Δρmax, Δρmin (e Å−3) | 0.48, −0.52 |
Selected bond lengths (Å) topAl1—O3 | 1.7357 (7) | B4—O2 | 1.3536 (12) |
Al1—O2 | 1.7405 (7) | B4—O9ii | 1.3931 (12) |
Al1—O1 | 1.7414 (7) | B5—O7 | 1.4421 (12) |
Al1—O4 | 1.7491 (7) | B5—O10iii | 1.4586 (13) |
B1—O1 | 1.3502 (12) | B5—O5iv | 1.4885 (12) |
B1—O8 | 1.3591 (12) | B5—O8ii | 1.5124 (12) |
B1—O9 | 1.3976 (12) | Li1—O2 | 1.964 (2) |
B2—O3 | 1.3495 (11) | Li2—O4 | 1.988 (2) |
B2—O5 | 1.3556 (12) | Li2—O5 | 1.952 (2) |
B2—O6 | 1.4013 (12) | Li1—O8 | 1.932 (2) |
B3—O10 | 1.3447 (12) | Li1—O6v | 1.955 (2) |
B3—O4 | 1.3644 (12) | Li1—O3v | 2.030 (2) |
B3—O6i | 1.3917 (12) | Li2—O9vi | 1.970 (2) |
B4—O7 | 1.3469 (12) | Li2—O1vi | 2.063 (2) |
Symmetry codes: (i) x, y, z−1; (ii) x+1, y, z; (iii) −x+1, y−1/2, −z−1/2; (iv) −x+1, y−1/2, −z+1/2; (v) x, −y+1/2, z−1/2; (vi) −x, −y+1, −z. |
This work is one of a series of studies aiming to explore new optical materials. Up to now, many optical materials have been found in borates. According to previous work (Cheng & Lu, 1997), the excellent optical properties of LiB3O5, one of the most important nonlinear optical crystals, mainly come from its anionic groups, [B3O7]5-. The [B3O7]5- group consists of two BO3 triangles and one BO4 tetrahedron and forms a hexagonal B—O ring. Hoping to synthesize new optical material, we are trying to introduce aluminium into alkali metal borates. Recently, a new compound, LiAlB2O5 (He et al., 2001) has been reported and its structure was determined from powder diffraction data. In this structure, Al substitutes the tetracoordinated B in [B3O7]5- rings and a new anionic group, [AlB2O7]5-, is formed. When the ratio of Li:(Al+B):O = 1:3:5 was kept but the ratio of Al:B was lowered to 1:5 from 1:2, the title compound was found to exist. This new compound crystallizes in a monoclinic space group P21/c and its structure can be characterized as a three-dimensional network of [B5O10]5- groups and AlO4 tetrahedra. The [B5O10]5- group consists of two planar hexagonal B—O rings linked by a tetracoordinated B and these two rings are perpendicular to each other. Moreover, all the B—O rings in this structure can be divided into two groups: one group is approximately parallel and the other perpendicular to the c axis (shown in Fig. 1). The unique configuration of planar B—O rings in this structure suggests that the title compound my be an excellent birefringent material. Unlike the Al atoms in LiAlB2O5, where Al atoms act much like tetracoordinated B, Al atoms in the title compound just connect with four different [B5O10]5- groups through O atoms and are not part of the B—O rings. In other words, [B5O10]5- groups are separated from each other completely by AlO4 tetrahedra. The Li+ cations are tetracoordinated with the Li—O distances ranging from 1.932 (2) to 2.063 (2) Å. The displacement ellipsoids of the asymmetry unit was shown in Fig. 2.