Monoclinic SmAl₃(BO₃)₄: synthesis, structural and spectroscopic properties

Single crystals of SmAl₃(BO₃)₄ were synthesized by the group growth on seeds method. The crystal structure was solved using a single-crystal experiment and the purity of the bulk material was proved by the Rietveld method. This borate crystallizes in the monoclinic C2/c space group with unit-cell parameters a = 7.2386 (3), b = 9.3412 (5), c = 11.1013 (4) Å and β = 103.2240 (10)°. IR and Raman spectroscopic analyses confirmed the monoclinic structure of SmAl₃(BO₃)₄. Under 532.1 nm excitation, luminescence spectra exhibit bands assignable to the transitions from ⁴G_5/2 to ⁶H_5/2, ⁶H_7/2, ⁶H_9/2 and ⁶H_11/2. The similarity of the luminescence spectra of the trigonal and monoclinic poly­morphs is explained by the minor role of Sm—O bond distortion and the primary role of rotational distortion of SmO₆ octa­hedra. The smaller covalency of the Sm—O bond in alumoborates is deduced in comparison with galloborates. Calorimetric measurements did not reveal high-temperature structural phase transitions up to a temperature of 720 K.

Computing details

Data collection: APEX2 (Bruker, 2008); cell refinement: APEX2 (Bruker, 2008); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: publCIF (Westrip, 2009).

(I)

Crystal data

Al3B4O12Sm	F(000) = 868
Mr = 466.54	Dx = 4.241 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.2386 (3) Å	Cell parameters from 7882 reflections
b = 9.3412 (3) Å	θ = 3.6–39.0°
c = 11.1013 (4) Å	µ = 8.49 mm^−1
β = 103.224 (1)°	T = 296 K
V = 730.73 (5) Å^3	Block, colorless
Z = 4	0.4 × 0.4 × 0.2 mm

Data collection

`SMART diffractometer	2018 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.039
Absorption correction: multi-scan (SADABS; Bruker, 2004)	θmax = 39.0°, θmin = 3.6°
Tmin = 0.578, Tmax = 0.745	h = −12→12
7882 measured reflections	k = −15→16
2025 independent reflections	l = −18→19

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0126P)^2 + 8.0294P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.026	(Δ/σ)max = 0.001
wR(F^2) = 0.063	Δρmax = 4.52 e Å^−3
S = 1.20	Δρmin = −3.06 e Å^−3
2025 reflections	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
93 parameters	Extinction coefficient: 0.170 (4)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
Sm	0.5000	0.46392 (2)	0.7500	0.00459 (9)
Al1	0.44437 (12)	0.25008 (9)	0.47154 (8)	0.00380 (14)
Al2	0.5000	−0.08861 (12)	0.7500	0.00388 (18)
B1	0.7512 (4)	0.4709 (3)	0.5046 (3)	0.0043 (4)
B2	0.6929 (4)	0.1864 (3)	0.7220 (3)	0.0046 (4)
O1	0.9037 (3)	0.3968 (2)	0.57387 (18)	0.0048 (3)
O2	0.5944 (3)	0.4023 (2)	0.43632 (18)	0.0055 (3)
O3	0.8398 (3)	0.2634 (2)	0.79484 (18)	0.0050 (3)
O4	0.7499 (3)	0.6195 (2)	0.4973 (2)	0.0059 (3)
O5	0.5605 (3)	0.2595 (2)	0.63779 (18)	0.0058 (3)
O6	0.6883 (3)	0.0423 (2)	0.7411 (2)	0.0059 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sm	0.00398 (10)	0.00505 (11)	0.00505 (10)	0.000	0.00164 (5)	0.000
Al1	0.0027 (3)	0.0049 (3)	0.0039 (3)	0.0002 (2)	0.0011 (2)	−0.0001 (2)
Al2	0.0034 (4)	0.0037 (4)	0.0048 (4)	0.000	0.0014 (3)	0.000
B1	0.0038 (10)	0.0045 (10)	0.0046 (10)	0.0005 (7)	0.0014 (8)	0.0003 (7)
B2	0.0042 (9)	0.0044 (9)	0.0049 (9)	−0.0012 (7)	0.0005 (7)	−0.0002 (7)
O1	0.0036 (6)	0.0058 (7)	0.0044 (6)	0.0016 (5)	0.0000 (5)	−0.0004 (5)
O2	0.0037 (6)	0.0059 (7)	0.0064 (7)	−0.0018 (5)	0.0002 (5)	0.0009 (5)
O3	0.0039 (6)	0.0066 (7)	0.0042 (6)	−0.0027 (5)	0.0001 (5)	0.0005 (5)
O4	0.0045 (7)	0.0053 (7)	0.0090 (7)	−0.0001 (5)	0.0037 (5)	0.0001 (6)
O5	0.0047 (7)	0.0069 (7)	0.0048 (7)	0.0015 (5)	−0.0008 (5)	0.0003 (5)
O6	0.0051 (7)	0.0044 (7)	0.0089 (8)	−0.0014 (5)	0.0030 (6)	−0.0005 (5)

Geometric parameters (Å, º)

Sm—O6^i	2.353 (2)	Al2—O1^x	1.9245 (19)
Sm—O6^ii	2.353 (2)	Al2—O3^vii	1.941 (2)
Sm—O5^iii	2.374 (2)	Al2—O3^x	1.941 (2)
Sm—O5	2.374 (2)	Al2—Al1^ix	2.9898 (10)
Sm—O2^iv	2.379 (2)	Al2—Al1^xi	2.9898 (10)
Sm—O2^v	2.379 (2)	B1—O2	1.371 (4)
Sm—B2^iii	2.994 (3)	B1—O1	1.378 (3)
Sm—B2	2.994 (3)	B1—O4	1.391 (3)
Sm—B2^i	3.007 (3)	B1—Sm^v	3.052 (3)
Sm—B2^ii	3.007 (3)	B2—O5	1.360 (3)
Sm—B1^iv	3.052 (3)	B2—O6	1.364 (3)
Sm—B1^v	3.052 (3)	B2—O3	1.382 (3)
Al1—O5	1.847 (2)	B2—Sm^xii	3.007 (3)
Al1—O2	1.884 (2)	O1—Al1^vi	1.898 (2)
Al1—O1^vi	1.898 (2)	O1—Al2^xiii	1.9245 (19)
Al1—O4^vii	1.932 (2)	O2—Sm^v	2.379 (2)
Al1—O3^viii	1.938 (2)	O3—Al1^xiv	1.938 (2)
Al1—O4^v	1.951 (2)	O3—Al2^xiii	1.941 (2)
Al1—Al2^ix	2.9898 (10)	O4—Al1^xiii	1.932 (2)
Al2—O6	1.851 (2)	O4—Al1^v	1.951 (2)
Al2—O6^iii	1.851 (2)	O6—Sm^xii	2.353 (2)
Al2—O1^vii	1.9245 (19)
O6^i—Sm—O6^ii	143.72 (9)	O4^vii—Al1—O3^viii	88.84 (9)
O6^i—Sm—O5^iii	121.22 (7)	O5—Al1—O4^v	88.54 (9)
O6^ii—Sm—O5^iii	88.98 (7)	O2—Al1—O4^v	92.22 (9)
O6^i—Sm—O5	88.98 (7)	O1^vi—Al1—O4^v	169.77 (10)
O6^ii—Sm—O5	121.22 (7)	O4^vii—Al1—O4^v	77.81 (10)
O5^iii—Sm—O5	72.96 (10)	O3^viii—Al1—O4^v	95.14 (9)
O6^i—Sm—O2^iv	73.61 (7)	O5—Al1—Al2^ix	136.89 (7)
O6^ii—Sm—O2^iv	87.43 (7)	O2—Al1—Al2^ix	91.01 (7)
O5^iii—Sm—O2^iv	90.97 (7)	O1^vi—Al1—Al2^ix	38.86 (6)
O5—Sm—O2^iv	145.86 (7)	O4^vii—Al1—Al2^ix	92.46 (7)
O6^i—Sm—O2^v	87.43 (7)	O3^viii—Al1—Al2^ix	39.62 (6)
O6^ii—Sm—O2^v	73.61 (7)	O4^v—Al1—Al2^ix	134.37 (7)
O5^iii—Sm—O2^v	145.86 (7)	O6—Al2—O6^iii	97.26 (14)
O5—Sm—O2^v	90.97 (7)	O6—Al2—O1^vii	95.30 (9)
O2^iv—Sm—O2^v	116.64 (10)	O6^iii—Al2—O1^vii	90.06 (9)
O6^i—Sm—B2^iii	136.94 (7)	O6—Al2—O1^x	90.06 (9)
O6^ii—Sm—B2^iii	78.96 (7)	O6^iii—Al2—O1^x	95.30 (9)
O5^iii—Sm—B2^iii	26.24 (7)	O1^vii—Al2—O1^x	171.89 (14)
O5—Sm—B2^iii	60.30 (7)	O6—Al2—O3^vii	167.13 (9)
O2^iv—Sm—B2^iii	114.36 (7)	O6^iii—Al2—O3^vii	88.09 (9)
O2^v—Sm—B2^iii	119.80 (7)	O1^vii—Al2—O3^vii	96.39 (9)
O6^i—Sm—B2	78.96 (7)	O1^x—Al2—O3^vii	77.76 (8)
O6^ii—Sm—B2	136.94 (7)	O6—Al2—O3^x	88.09 (9)
O5^iii—Sm—B2	60.31 (7)	O6^iii—Al2—O3^x	167.13 (9)
O5—Sm—B2	26.24 (7)	O1^vii—Al2—O3^x	77.76 (8)
O2^iv—Sm—B2	119.80 (7)	O1^x—Al2—O3^x	96.39 (9)
O2^v—Sm—B2	114.36 (7)	O3^vii—Al2—O3^x	89.15 (13)
B2^iii—Sm—B2	60.04 (11)	O6—Al2—Al1^ix	92.86 (7)
O6^i—Sm—B2^i	26.00 (7)	O6^iii—Al2—Al1^ix	128.09 (7)
O6^ii—Sm—B2^i	117.94 (7)	O1^vii—Al2—Al1^ix	38.22 (6)
O5^iii—Sm—B2^i	136.23 (7)	O1^x—Al2—Al1^ix	135.59 (7)
O5—Sm—B2^i	112.91 (7)	O3^vii—Al2—Al1^ix	93.00 (7)
O2^iv—Sm—B2^i	59.24 (7)	O3^x—Al2—Al1^ix	39.55 (6)
O2^v—Sm—B2^i	77.61 (7)	O6—Al2—Al1^xi	128.09 (7)
B2^iii—Sm—B2^i	159.87 (10)	O6^iii—Al2—Al1^xi	92.86 (7)
B2—Sm—B2^i	104.943 (18)	O1^vii—Al2—Al1^xi	135.59 (7)
O6^i—Sm—B2^ii	117.94 (7)	O1^x—Al2—Al1^xi	38.22 (6)
O6^ii—Sm—B2^ii	26.00 (7)	O3^vii—Al2—Al1^xi	39.55 (6)
O5^iii—Sm—B2^ii	112.90 (7)	O3^x—Al2—Al1^xi	93.00 (7)
O5—Sm—B2^ii	136.23 (7)	Al1^ix—Al2—Al1^xi	119.40 (5)
O2^iv—Sm—B2^ii	77.61 (7)	O2—B1—O1	122.0 (2)
O2^v—Sm—B2^ii	59.24 (7)	O2—B1—O4	116.1 (2)
B2^iii—Sm—B2^ii	104.943 (18)	O1—B1—O4	121.8 (2)
B2—Sm—B2^ii	159.87 (10)	O2—B1—Sm^v	48.60 (13)
B2^i—Sm—B2^ii	92.56 (10)	O1—B1—Sm^v	148.06 (18)
O6^i—Sm—B1^iv	62.37 (8)	O4—B1—Sm^v	75.65 (14)
O6^ii—Sm—B1^iv	109.85 (8)	O5—B2—O6	124.3 (2)
O5^iii—Sm—B1^iv	79.46 (7)	O5—B2—O3	117.9 (2)
O5—Sm—B1^iv	120.26 (7)	O6—B2—O3	117.7 (2)
O2^iv—Sm—B1^iv	25.61 (7)	O5—B2—Sm	50.53 (13)
O2^v—Sm—B1^iv	133.79 (7)	O6—B2—Sm	144.07 (19)
B2^iii—Sm—B1^iv	105.66 (7)	O3—B2—Sm	78.67 (15)
B2—Sm—B1^iv	94.34 (7)	O5—B2—Sm^xii	143.75 (19)
B2^i—Sm—B1^iv	59.76 (7)	O6—B2—Sm^xii	49.14 (13)
B2^ii—Sm—B1^iv	103.16 (7)	O3—B2—Sm^xii	81.20 (16)
O6^i—Sm—B1^v	109.85 (8)	Sm—B2—Sm^xii	159.87 (10)
O6^ii—Sm—B1^v	62.37 (8)	B1—O1—Al1^vi	130.79 (17)
O5^iii—Sm—B1^v	120.26 (7)	B1—O1—Al2^xiii	126.12 (17)
O5—Sm—B1^v	79.46 (7)	Al1^vi—O1—Al2^xiii	102.93 (9)
O2^iv—Sm—B1^v	133.79 (7)	B1—O2—Al1	132.98 (18)
O2^v—Sm—B1^v	25.61 (7)	B1—O2—Sm^v	105.79 (16)
B2^iii—Sm—B1^v	94.34 (7)	Al1—O2—Sm^v	120.82 (9)
B2—Sm—B1^v	105.66 (7)	B2—O3—Al1^xiv	128.95 (18)
B2^i—Sm—B1^v	103.16 (7)	B2—O3—Al2^xiii	130.22 (18)
B2^ii—Sm—B1^v	59.76 (7)	Al1^xiv—O3—Al2^xiii	100.83 (9)
B1^iv—Sm—B1^v	156.97 (10)	B1—O4—Al1^xiii	130.04 (17)
O5—Al1—O2	91.09 (10)	B1—O4—Al1^v	127.50 (16)
O5—Al1—O1^vi	98.12 (9)	Al1^xiii—O4—Al1^v	102.19 (10)
O2—Al1—O1^vi	95.39 (9)	B2—O5—Al1	138.67 (18)
O5—Al1—O4^vii	93.61 (10)	B2—O5—Sm	103.23 (16)
O2—Al1—O4^vii	168.85 (10)	Al1—O5—Sm	117.80 (10)
O1^vi—Al1—O4^vii	93.95 (9)	B2—O6—Al2	134.82 (19)
O5—Al1—O3^viii	175.94 (10)	B2—O6—Sm^xii	104.86 (17)
O2—Al1—O3^viii	87.08 (9)	Al2—O6—Sm^xii	120.19 (10)
O1^vi—Al1—O3^viii	78.47 (9)

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