LaZnB₅O₁₀, the first lanthanum zinc borate

Lanthanum zinc penta­borate, LaZnB₅O₁₀, was synthesized by flux-supported solid-state reaction. It is a member of the LnMB₅O₁₀ (Ln = rare earth ion and M = divalent metal ion) structure type. The crystal shows a three-dimensional structure constructed from two-dimensional {[B₅O₁₀]⁵⁻}_n layers with the lanthanum (coordination number nine) and zinc (coordination number six) ions filling in the inter­layers.

Related literature

For general background to inorganic borates and their applications, see: Thakare et al. (2004); Yavetskiy et al. (2007); Ye & Chai (1999); Becker (1998). For related structures, see: Bernadette et al. (1980); Abdullaev et al. (1980); Campa et al. (1995). For the bond-valence-sum (BVS) calculation, see: Brese & O'Keeffe (1991).

Experimental

Crystal data

• LaZnB₅O₁₀

• M_r = 418.33

• Monoclinic, P 2₁ /n

• a = 8.7923 (19) Å

• b = 7.629 (2) Å

• c = 9.566 (2) Å

• β = 92.667 (19)°

• V = 641.0 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 10.37 mm⁻¹

• T = 295 K

• 0.10 × 0.08 × 0.06 mm

Data collection

• Bruker P4 diffractometer

• Absorption correction: ψ scan (North et al., 1968) T_min = 0.259, T_max = 0.347

• 3122 measured reflections

• 2318 independent reflections

• 2174 reflections with I > 2σ(I)

• R_int = 0.033

• 3 standard reflections every 97 reflections intensity decay: none

Refinement

• R[F² > 2σ(F²)] = 0.036

• wR(F²) = 0.086

• S = 1.01

• 2318 reflections

• 155 parameters

• Δρ_max = 3.81 e Å⁻³

• Δρ_min = −1.63 e Å⁻³

Data collection: XSCANS (Bruker, 1997); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXL97.

Supporting information

S1. Comment

Inorganic borates have long been a focus of research for their wide applications as phosphors, laser materials and nonlinear optical (NLO) materials etc (Thakare et al., 2004; Yavetskiy et al., 2007; Ye et al., 1999; Becker et al., 1998). Among these materials, rear-earth borates especially lanthanum or yttrium borates, have been proved to be attractive matrices for lasing materials or rare-earths sensitizer-activator pairs containing phosphors. LaZnB₅O₁₀ is a new member of the family of LnMB₅O₁₀ (Ln = rear earth ions, M = divalent metal ions) (Abdullaev et al., 1980; Bernadette et al., 1980; Campa et al., 1995). The asymmetric unit of LaZnB₅O₁₀ contains one unique La ion, one Zn ion, five B atoms and ten oxygen atoms as shown in Fig.1. Three BO₄ tetrahedra and two BO₃ triangles are linked to form a B₅O₁₂ double-ring group (Fig.2a), and these B₅O₁₂ groups are further connected to form a [B₅O₁₀]^5-_n layer through sharing BO₄ tetrahedra.

The local coordination geometries of Zn and La atoms in LaZnB₅O₁₀ are also shown in Fig.2. As can be observed, the La1 atom is bonded to nine oxygen atoms to form a distorted tetrakaidecahedron. The bond valence sum (BVS) of 3.143 for La³⁺ ions calculated by the Brese & Keeffe (Brese et al., 1991) formalism shows that its valence requirement is satisfied by this coordination. The distorted tetrakaidecahedra here are further connected with each other through sharing edges to form a one-dimensional infinite chain which is arranged between the [B₅O₁₀]^5-_n layers along b axis. The zinc cation adopts a sixfolded coordination to form a distorted octahedron. However, among these Zn—O bonds, Zn1—O1 and Zn1—O4 are significantly longer than the others. This could be probably due to the fact that the O1-O4 edge is shared with a BO₃ group. This reduces the O1-Zn-O4 angle and tends to lengthen the bonds. Two adjacent ZnO₆ octahedra are connected with each other through two bridging oxygen atoms and the zinc atoms are almost embedded in the [B₅O₁₀]^5-_n layers. Both the zinc and lanthanum atoms link the adjacent [B₅O₁₀]^5-_n layers to form a three dimensional framework (Fig.3).

Related literature

For general background to inorganic borates and their applications, see: Thakare et al. (2004); Yavetskiy et al. (2007); Ye et al. (1999); Becker et al. (1998). For related structures, see: Bernadette et al. (1980); Abdullaev et al. (1980); Campa et al. (1995). For the bond-valence-sum (BVS) calculation, see: Brese et al. (1991).

S2. Experimental

Single crystals of the title compound were synthesized by flux-supported solid-state reaction. A mixture La₂O₃(99.9%), ZnO(99.0%) and H₃BO₃(99.99%) in the molar ratio of 1:2:14 was ground to a fine powder in a mortar and compressed into a Pt crucible. The mixture was gradually heated to 1273 K. After the mixture melted completely, it was cooled down to 1100 K at a rate of 1 °K/h, followed by cooling to room temperature at 20 °K/h. The title crystals could be obtained from the top section of the solidified melt. While in the bottom of the solidified melt, plate-like crystals were obtained which were confirmed to be LaB₃O₆ through the powder X-ray diffraction (PXRD) method.

Computing details

Data collection: XSCANS (Bruker, 2001); cell refinement: XSCANS (Bruker, 2001); data reduction: XSCANS (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. ORTEP drawing of LaZnB5O10 with 35% probability ellipsoids, showing the atomic numbering scheme.
	Fig. 2. (a) The B5O12 double-ring group; (b) The coordination environment of the La atom; (c) The coordination environment of the Zn atom. The blue polyhedra are the [BO3] triangles while the purple polyhedra are the [BO4] tetrahedra in the lower two figures.
	Fig. 3. The representation of the three-dimensional LaZnB5O10 structure projected along the [010] direction with the BO3 triangles and BO4 tetrahedra. The structure contains the infinite two-dimensional [B5O10]^5-n layers running almost perpendicular to the [101] direction. The La atoms are located in layers, while the Zn atoms are almost embedded in the layers.

Lanthanum zinc pentaborate

Crystal data

LaZnB5O10	F(000) = 768
Mr = 418.33	Dx = 4.335 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 36 reflections
a = 8.7923 (19) Å	θ = 5.8–12.5°
b = 7.629 (2) Å	µ = 10.37 mm^−1
c = 9.566 (2) Å	T = 295 K
β = 92.667 (19)°	Prism, colorless
V = 641.0 (3) Å^3	0.10 × 0.08 × 0.06 mm
Z = 4

Data collection

Bruker P4 diffractometer	2174 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.033
Graphite monochromator	θmax = 32.5°, θmin = 3.1°
ω scans	h = −13→1
Absorption correction: ψ scan (North et al., 1968)	k = −1→11
Tmin = 0.259, Tmax = 0.347	l = −14→14
3122 measured reflections	3 standard reflections every 97 reflections
2318 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	w = 1/[σ^2(Fo^2) + (0.001P)^2 + 14.P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.086	(Δ/σ)max < 0.001
S = 1.01	Δρmax = 3.81 e Å^−3
2318 reflections	Δρmin = −1.63 e Å^−3
155 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.133 (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
La1	0.18084 (3)	0.68446 (4)	0.23425 (3)	0.00861 (13)
Zn1	0.88916 (7)	0.41215 (8)	0.38049 (7)	0.01160 (16)
O1	0.4743 (4)	0.7209 (5)	0.2592 (4)	0.0097 (6)
O2	0.5128 (4)	0.4196 (5)	0.1869 (4)	0.0105 (6)
O3	0.6830 (4)	0.5372 (5)	0.3613 (4)	0.0104 (6)
O4	0.5839 (4)	0.9780 (5)	0.3570 (4)	0.0099 (6)
O5	0.3289 (4)	0.8921 (5)	0.4150 (4)	0.0097 (6)
O6	0.5383 (4)	0.7202 (5)	0.5088 (4)	0.0102 (6)
O7	0.8125 (4)	1.1547 (5)	0.3721 (4)	0.0100 (6)
O8	0.6912 (4)	0.3737 (5)	0.0101 (4)	0.0098 (6)
O9	0.5056 (4)	0.1522 (5)	0.0688 (4)	0.0101 (6)
O10	0.7299 (4)	0.5391 (5)	0.6081 (4)	0.0112 (6)
B1	0.5877 (6)	0.5824 (7)	0.2330 (5)	0.0082 (8)
B2	0.5734 (6)	0.3144 (7)	0.0839 (6)	0.0096 (9)
B3	0.4843 (6)	0.8275 (7)	0.3895 (6)	0.0092 (9)
B4	0.7168 (6)	1.0340 (7)	0.4479 (5)	0.0093 (9)
B5	0.6498 (6)	0.5943 (7)	0.4924 (6)	0.0092 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
La1	0.00934 (16)	0.00822 (17)	0.00831 (16)	0.00018 (8)	0.00087 (9)	0.00037 (8)
Zn1	0.0114 (3)	0.0094 (3)	0.0140 (3)	0.0001 (2)	0.0000 (2)	−0.0002 (2)
O1	0.0091 (14)	0.0105 (15)	0.0095 (14)	−0.0007 (12)	0.0003 (11)	0.0014 (12)
O2	0.0115 (15)	0.0104 (15)	0.0098 (14)	−0.0014 (12)	0.0028 (12)	−0.0009 (12)
O3	0.0126 (15)	0.0104 (15)	0.0083 (14)	0.0029 (12)	0.0006 (11)	−0.0016 (12)
O4	0.0096 (14)	0.0099 (15)	0.0100 (14)	−0.0025 (12)	−0.0002 (11)	0.0007 (12)
O5	0.0073 (14)	0.0135 (16)	0.0085 (14)	0.0028 (12)	0.0008 (11)	−0.0006 (12)
O6	0.0107 (14)	0.0082 (14)	0.0117 (15)	0.0026 (12)	0.0010 (12)	0.0003 (12)
O7	0.0100 (15)	0.0087 (14)	0.0116 (15)	−0.0003 (12)	0.0033 (12)	−0.0006 (12)
O8	0.0108 (15)	0.0085 (15)	0.0103 (14)	−0.0028 (12)	0.0036 (12)	−0.0011 (12)
O9	0.0121 (15)	0.0087 (15)	0.0098 (15)	−0.0018 (12)	0.0018 (12)	−0.0004 (12)
O10	0.0121 (15)	0.0114 (16)	0.0099 (14)	0.0014 (13)	−0.0001 (12)	0.0020 (12)
B1	0.010 (2)	0.007 (2)	0.0076 (19)	0.0018 (16)	0.0003 (16)	0.0002 (16)
B2	0.008 (2)	0.012 (2)	0.009 (2)	0.0015 (17)	0.0019 (16)	−0.0001 (17)
B3	0.009 (2)	0.010 (2)	0.009 (2)	0.0031 (17)	0.0014 (16)	−0.0008 (16)
B4	0.010 (2)	0.010 (2)	0.0080 (19)	0.0003 (17)	0.0009 (16)	0.0005 (16)
B5	0.009 (2)	0.009 (2)	0.010 (2)	0.0006 (16)	0.0027 (16)	0.0002 (17)

Geometric parameters (Å, º)

La1—O10^i	2.385 (4)	B2—O2	1.396 (6)
La1—O10^ii	2.478 (4)	B1—O2	1.464 (7)
La1—O6^ii	2.549 (4)	B5—O3	1.372 (6)
La1—O9^iii	2.566 (4)	B1—O3	1.495 (6)
La1—O1	2.595 (4)	B3—O4	1.486 (7)
La1—O2^iii	2.608 (4)	B4—O4	1.486 (7)
La1—O5	2.643 (4)	B3—O5	1.484 (6)
La1—O5^iv	2.648 (4)	B4—O5^x	1.500 (6)
La1—O8^v	2.678 (4)	B5—O6	1.387 (6)
Zn1—O3	2.049 (4)	B3—O6	1.466 (7)
Zn1—O7^vi	2.077 (4)	B4—O7	1.462 (7)
Zn1—O9^vii	2.088 (4)	B1—O7^ix	1.472 (6)
Zn1—O9^viii	2.099 (4)	B2—O8	1.358 (6)
Zn1—O1^ix	2.346 (4)	B4—O8^viii	1.511 (7)
Zn1—O4^ix	2.350 (4)	B2—O9	1.378 (7)
B1—O1	1.482 (6)	B5—O10	1.351 (6)
B3—O1	1.488 (7)
O10^i—La1—O10^ii	148.99 (6)	O7^vi—Zn1—O9^vii	87.47 (15)
O10^i—La1—O6^ii	150.84 (13)	O3—Zn1—O9^viii	89.60 (15)
O10^ii—La1—O6^ii	55.60 (12)	O7^vi—Zn1—O9^viii	166.66 (15)
O10^i—La1—O9^iii	70.71 (13)	O9^vii—Zn1—O9^viii	79.20 (16)
O10^ii—La1—O9^iii	124.81 (12)	O3—Zn1—O1^ix	135.44 (14)
O6^ii—La1—O9^iii	110.05 (12)	O7^vi—Zn1—O1^ix	64.12 (14)
O10^i—La1—O1	73.86 (13)	O9^vii—Zn1—O1^ix	95.83 (14)
O10^ii—La1—O1	76.04 (12)	O9^viii—Zn1—O1^ix	116.27 (14)
O6^ii—La1—O1	119.66 (12)	O3—Zn1—O4^ix	86.69 (14)
O9^iii—La1—O1	127.52 (12)	O7^vi—Zn1—O4^ix	102.25 (14)
O10^i—La1—O2^iii	120.59 (12)	O9^vii—Zn1—O4^ix	144.77 (14)
O10^ii—La1—O2^iii	71.71 (12)	O9^viii—Zn1—O4^ix	88.49 (14)
O6^ii—La1—O2^iii	75.30 (12)	O1^ix—Zn1—O4^ix	60.35 (13)
O9^iii—La1—O2^iii	53.55 (12)	O2—B1—O7^ix	112.7 (4)
O1—La1—O2^iii	124.01 (12)	O2—B1—O1	111.0 (4)
O10^i—La1—O5	82.96 (13)	O7^ix—B1—O1	106.0 (4)
O10^ii—La1—O5	73.55 (12)	O2—B1—O3	106.2 (4)
O6^ii—La1—O5	126.16 (12)	O7^ix—B1—O3	108.5 (4)
O9^iii—La1—O5	83.62 (12)	O1—B1—O3	112.4 (4)
O1—La1—O5	54.44 (12)	O8—B2—O9	125.6 (5)
O2^iii—La1—O5	72.95 (12)	O8—B2—O2	120.1 (5)
O10^i—La1—O5^iv	74.93 (12)	O9—B2—O2	114.4 (4)
O10^ii—La1—O5^iv	117.16 (12)	O6—B3—O5	108.9 (4)
O6^ii—La1—O5^iv	77.42 (12)	O6—B3—O4	115.0 (4)
O9^iii—La1—O5^iv	108.04 (12)	O5—B3—O4	109.5 (4)
O1—La1—O5^iv	98.43 (12)	O6—B3—O1	110.6 (4)
O2^iii—La1—O5^iv	136.90 (12)	O5—B3—O1	107.5 (4)
O5—La1—O5^iv	149.36 (8)	O4—B3—O1	105.1 (4)
O10^i—La1—O8^v	107.11 (12)	O7—B4—O4	110.2 (4)
O10^ii—La1—O8^v	68.05 (12)	O7—B4—O5^x	112.4 (4)
O6^ii—La1—O8^v	61.25 (12)	O4—B4—O5^x	112.6 (4)
O9^iii—La1—O8^v	159.02 (12)	O7—B4—O8^viii	109.2 (4)
O1—La1—O8^v	69.00 (12)	O4—B4—O8^viii	108.6 (4)
O2^iii—La1—O8^v	132.27 (12)	O5^x—B4—O8^viii	103.5 (4)
O5—La1—O8^v	117.15 (11)	O10—B5—O3	121.6 (5)
O5^iv—La1—O8^v	52.70 (11)	O10—B5—O6	117.9 (4)
O3—Zn1—O7^vi	98.79 (16)	O3—B5—O6	120.4 (5)
O3—Zn1—O9^vii	125.64 (15)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1/2, −y+3/2, z−1/2; (iii) −x+1/2, y+1/2, −z+1/2; (iv) −x+1/2, y−1/2, −z+1/2; (v) −x+1, −y+1, −z; (vi) x, y−1, z; (vii) x+1/2, −y+1/2, z+1/2; (viii) −x+3/2, y+1/2, −z+1/2; (ix) −x+3/2, y−1/2, −z+1/2; (x) −x+1, −y+2, −z+1.