Trilithium scandium bis­(orthoborate)

Abstract

Single crystals of the title compound, Li₃Sc(BO₃)₂, have been obtained by spontaneous nucleation from a high-temperature melt. The title compound adopts a framework structure and is composed of distorted [ScO₆] octa­hedra, [LiO₄] tetra­hedra, [LiO₄] recta­ngles and isolated [BO₃] triangles. Except for the Sc and one Li atom (both on inversion centres), all atoms are in general positions.

Related literature

For a review of structural data of BO₃ groups, see: Zobetz (1982 ▶). For sodium scandium borates, see: Becker & Held (2001 ▶); Zhang et al. (2006 ▶).

Experimental

Crystal data

• Li₃Sc(BO₃)₂

• M _r = 183.4

• Monoclinic,

• a = 4.7831 (17) Å

• b = 5.954 (2) Å

• c = 8.163 (3) Å

• β = 90.702 (9)°

• V = 232.44 (15) ų

• Z = 2

• Mo Kα radiation

• μ = 1.53 mm⁻¹

• T = 293 (2) K

• 0.12 × 0.10 × 0.10 mm

Data collection

• Rigaku Mercury CCD diffractometer

• Absorption correction: multi-scan (CrystalClear; Rigaku, 2000 ▶) T _min = 0.833, T _max = 0.858

• 1734 measured reflections

• 534 independent reflections

• 518 reflections with I > 2σ(I)

• R _int = 0.015

Refinement

• R[F ² > 2σ(F ²)] = 0.017

• wR(F ²) = 0.058

• S = 1.10

• 534 reflections

• 58 parameters

• Δρ_max = 0.28 e Å⁻³

• Δρ_min = −0.23 e Å⁻³

Data collection: CrystalClear (Rigaku, 2000 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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: enCIFer (Allen et al., 2004 ▶).

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Sc—O1	2.0854 (12)
Sc—O2i	2.1101 (12)
Sc—O3i	2.1197 (13)
Li1—O2	2.0107 (12)
Li1—O1ii	2.1173 (12)
Li2—O1iii	1.896 (3)
Li2—O2	1.946 (3)
Li2—O3iv	1.983 (3)
Li2—O3i	2.137 (3)
B—O2	1.376 (2)
B—O3v	1.384 (2)
B—O1vi	1.385 (2)

O2—B—O3v	122.09 (14)
O2—B—O1vi	119.13 (14)
O3v—B—O1vi	118.72 (14)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

supplementary crystallographic information

Comment

Li₃Sc(BO₃)₂, (I), was found from analysis of phase equilibria in the system Li₂O—Sc₂O₃—B₂O₃, in which it is the first characterized pseudo-ternary phase. For the heavier Na homologue, two phases are already known, viz. Na₃Sc₂(BO₃)₃ (Zhang et al., 2006) and NaScB₂O₅ (Becker & Held, 2001).

The framework structure of (I) is made up of distorted [ScO₆] octahedra, [LiO₄] tetrahedra, [LiO₄] rectangles and [BO₃] triangles as single building units. The [ScO₆] octahedra are linked via [LiO₄] rectangles by sharing edges to form columns parallel to [010]. The columns are linked to each other through [LiO₄] tetrahedra and [BO₃] triangles by sharing edges and corners (Figs 1 and 2).

The B atom is coordinated to three oxygen atoms forming nearly trigonal planar [BO₃]^3- anions. The B—O bond lengths range from 1.376 (2) to 1.385 (2) Å, and the O—B—O angles are close to 120° (Table 1), values that are typical for BO₃ groups (Zobetz, 1982). The Sc³⁺ cation is coordinated by six oxygen atoms to form a distorted [ScO₆] ocahedron with Sc—O bond lengths ranging from 2.0854 (12) to 2.1197 (13) Å. There are two crystallographically different Li atoms. One is situated on an inversion centre (1 symmetry) and is coordinated to four oxygen atoms forming a nearly planar [LiO₄] rectangle with Li1—O bond lengths ranging from 2.0107 (12) to 2.1173 (12) Å. The other Li atom is also coordinated to four O atoms, but is in the centre of a distorted tetrahedron with Li2—O bond lengths from 1.896 (3) to 2.137 (3) Å (Table 1). The average Li—O bond length of the [Li1O₄] rectangle (2.064 Å) is slightly longer than that of the [Li2O₄] tetrahedron (1.991 Å).

Experimental

Single crystals of compound (I) were grown using a LiBO₂-containing flux. The composition of the mixture for crystal growth was 4:1:4 of Li₂CO₃ (Sinopharm Reagents, 99.99%), Sc₂O₃ (Sinopharm Reagents, 4 N), and B₂O₃ (Sinopharm Reagents, 99%). This mixture was heated in a platinum crucible to 1373 K, held at this temperature for several hours, and then cooled at a rate of 10 K/h from 1373 to 873 K. The remaining 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.

Figures

Fig. 1.

The structure of (I) in a projection approximatly along the [001] direction with displacement ellipsoids drawn at the 85% probability level.

Fig. 2.

The structure of (I) given in the polyhedral description. [ScO6] octahedra are blue, [LiO4] tetrahedra are green, [LiO4] rectangles are purple, and [BO3] units are yellow.

Crystal data

Li3Sc(BO3)2	F000 = 176
Mr = 183.4	Dx = 2.62 Mg m−3
Monoclinic, P21/n	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 623 reflections
a = 4.7831 (17) Å	θ = 4.2–23.6º
b = 5.954 (2) Å	µ = 1.53 mm−1
c = 8.163 (3) Å	T = 293 (2) K
β = 90.702 (9)º	Block, colourless
V = 232.44 (15) Å3	0.12 × 0.10 × 0.10 mm
Z = 2

Data collection

Rigaku Mercury CCD diffractometer	534 independent reflections
Radiation source: Sealed Tube	518 reflections with I > 2σ(I)
Monochromator: Graphite Monochromator	Rint = 0.015
Detector resolution: 14.6306 pixels mm-1	θmax = 27.5º
T = 293(1) K	θmin = 4.2º
CCD_Profile_fitting scans	h = −6→4
Absorption correction: multi-scan(CrystalClear; Rigaku, 2000)	k = −7→7
Tmin = 0.833, Tmax = 0.858	l = −10→10
1734 measured reflections

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	w = 1/[σ2(Fo2) + (0.0318P)2 + 0.216P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.017	(Δ/σ)max < 0.001
wR(F2) = 0.058	Δρmax = 0.28 e Å−3
S = 1.10	Δρmin = −0.23 e Å−3
534 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008)
58 parameters	Extinction coefficient: ?

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.

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

	x	y	z	Uiso*/Ueq
Sc	0	0	0	0.00510 (15)
Li1	0	−0.5	0	0.0209 (10)
Li2	−0.0144 (6)	−0.2513 (5)	0.2977 (4)	0.0133 (6)
B	0.5149 (4)	−0.3045 (3)	0.1254 (2)	0.0061 (3)
O1	0.3101 (2)	0.24622 (18)	0.00179 (14)	0.0077 (2)
O2	0.2330 (2)	−0.26155 (19)	0.11029 (14)	0.0086 (3)
O3	0.1280 (2)	−0.08686 (19)	−0.23947 (13)	0.0086 (3)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Sc	0.0050 (2)	0.0054 (2)	0.0049 (2)	−0.00002 (13)	0.00011 (14)	0.00009 (12)
Li1	0.015 (2)	0.012 (2)	0.035 (3)	0.0000 (15)	−0.008 (2)	−0.0062 (17)
Li2	0.0119 (13)	0.0182 (15)	0.0098 (13)	−0.0025 (11)	−0.0018 (10)	0.0015 (10)
B	0.0074 (7)	0.0042 (7)	0.0067 (7)	−0.0009 (6)	0.0000 (6)	−0.0014 (6)
O1	0.0065 (5)	0.0095 (5)	0.0070 (5)	−0.0013 (4)	0.0004 (4)	0.0005 (4)
O2	0.0060 (5)	0.0099 (5)	0.0099 (6)	0.0013 (4)	0.0000 (4)	0.0012 (4)
O3	0.0084 (5)	0.0102 (6)	0.0071 (5)	0.0006 (4)	−0.0009 (4)	−0.0023 (4)

Geometric parameters (Å, °)

Sc—O1	2.0854 (12)	Li2—O1x	1.896 (3)
Sc—O1i	2.0854 (12)	Li2—O2	1.946 (3)
Sc—O2i	2.1101 (12)	Li2—O3xi	1.983 (3)
Sc—O2	2.1101 (12)	Li2—O3i	2.137 (3)
Sc—O3i	2.1197 (13)	Li2—Bviii	2.659 (3)
Sc—O3	2.1197 (13)	Li2—Bxi	2.697 (3)
Sc—Li2i	2.855 (3)	Li2—Bxii	2.733 (4)
Sc—Li2	2.855 (3)	Li2—Scix	3.226 (3)
Sc—Li1ii	2.9768 (11)	Li2—Li1iii	3.234 (3)
Sc—Li1	2.9768 (11)	Li2—Scx	3.297 (3)
Sc—Li2iii	3.226 (3)	B—O2	1.376 (2)
Sc—Li2iv	3.226 (3)	B—O3xiii	1.384 (2)
Li1—O2	2.0107 (12)	B—O1xiv	1.385 (2)
Li1—O2v	2.0107 (12)	B—Li2xv	2.659 (3)
Li1—O1vi	2.1173 (12)	B—Li2iv	2.697 (3)
Li1—O1i	2.1173 (12)	B—Li2x	2.733 (4)
Li1—Bvii	2.8008 (18)	B—Li1xv	2.8008 (18)
Li1—Bviii	2.8008 (18)	O1—Bxiv	1.385 (2)
Li1—Li2v	2.847 (3)	O1—Li2xii	1.896 (3)
Li1—Li2	2.847 (3)	O1—Li1ii	2.1173 (12)
Li1—Scvi	2.9768 (11)	O3—Bxvi	1.384 (2)
Li1—Li2ix	3.234 (3)	O3—Li2iv	1.983 (3)
Li1—Li2iv	3.234 (3)	O3—Li2i	2.137 (3)
O1—Sc—O1i	180.00 (4)	O1x—Li2—O3i	109.04 (14)
O1—Sc—O2i	81.73 (5)	O2—Li2—O3i	90.58 (12)
O1i—Sc—O2i	98.27 (5)	O3xi—Li2—O3i	101.95 (13)
O1—Sc—O2	98.27 (5)	O2—B—O3xiii	122.09 (14)
O1i—Sc—O2	81.73 (5)	O2—B—O1xiv	119.13 (14)
O2i—Sc—O2	180.00 (8)	O3xiii—B—O1xiv	118.72 (14)
O1—Sc—O3i	92.04 (4)	Bxiv—O1—Li2xii	109.58 (13)
O1i—Sc—O3i	87.96 (4)	Bxiv—O1—Sc	127.37 (10)
O2i—Sc—O3i	93.23 (5)	Li2xii—O1—Sc	111.74 (11)
O2—Sc—O3i	86.77 (5)	Bxiv—O1—Li1ii	104.23 (9)
O1—Sc—O3	87.96 (4)	Li2xii—O1—Li1ii	110.73 (10)
O1i—Sc—O3	92.04 (4)	Sc—O1—Li1ii	90.19 (5)
O2i—Sc—O3	86.77 (5)	B—O2—Li2	122.67 (13)
O2—Sc—O3	93.23 (5)	B—O2—Li1	116.47 (10)
O3i—Sc—O3	180.00 (5)	Li2—O2—Li1	92.02 (10)
O2—Li1—O2v	180.00 (6)	B—O2—Sc	133.37 (10)
O2—Li1—O1vi	96.68 (5)	Li2—O2—Sc	89.39 (10)
O2v—Li1—O1vi	83.32 (5)	Li1—O2—Sc	92.47 (5)
O2—Li1—O1i	83.32 (5)	Bxvi—O3—Li2iv	102.89 (13)
O2v—Li1—O1i	96.68 (5)	Bxvi—O3—Sc	137.30 (10)
O1vi—Li1—O1i	180	Li2iv—O3—Sc	103.64 (10)
O1x—Li2—O2	111.51 (16)	Bxvi—O3—Li2i	99.62 (12)
O1x—Li2—O3xi	124.23 (16)	Li2iv—O3—Li2i	135.08 (11)
O2—Li2—O3xi	113.33 (15)	Sc—O3—Li2i	84.24 (9)

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