Redetermination of tricalcium trilanthanum penta­kis(ortho­borate) from single-crystal data

Single crystals of the title compound, Ca₃La₃(BO₃)₅, were obtained by spontaneous nucleation from a high-temperature melt. The crystal structure of Ca₃La₃(BO₃)₅ has been determined previously from X-ray powder data [Zhang, Liang, Chen, He & Xu (2001). J. Alloys Compd, 327, 96-99]. The present refinement shows a significant improvement in terms of the precision of the geometric parameters and the correct determination of the absolute configuration in space group P6₃mc with all atoms refined with anisotropic displacement parameters. The structure consists of isolated BO₃ triangles and distorted [CaO₈] and [LaO₁₀] polyhedra. Except for one O atom, all other atoms are situated on special positions: La, all O and one B atom on mirror planes, and two B atoms with site symmetry 3m.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](La-B) = 0.004 Å
• R factor = 0.012
• wR factor = 0.031
• Data-to-parameter ratio = 10.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT731_ALERT_1_C Bond    Calc    2.811(2), Rep   2.8112(8) ......       2.50 su-Ra
              LA1  -O3      1.555   6.554
PLAT731_ALERT_1_C Bond    Calc    2.811(2), Rep   2.8112(8) ......       2.50 su-Ra
              LA1  -O3      1.555   5.564

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.47
           From the CIF: _reflns_number_total                534
           Count of symmetry unique reflns          298
           Completeness (_total/calc)            179.19%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       236
           Fraction of Friedel pairs measured     0.792
           Are heavy atom types Z>Si present        yes
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
   2 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   4 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
   0 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

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S1. Comment

Borate crystals containing parallel 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, 1999). The title compound Ca₃La₃(BO₃)₅, (I), has been investigated previously by Zhang et al. (2001a) during analysis of phase equilibria in the system La₂O₃—CaO—B₂O₃, and NLO and luminescent properties of this material have also been reported (Zhang, 2005; Han, 2007). The crystal structure of Ca₃La₃ (BO₃)₅ was originally determined from X-ray powder diffraction data in conjunction with IR spectroscopy (Zhang et al., 2001b).

The structure of compound (I) can be described in terms of BO₃ triangles and complex irregular [CaO₈] and [LaO₁₀] polyhedra. Each of the three crystallographically different B atoms is coordinated to three O atoms to form planar BO₃ triangles. The B—O bond lengths range from 1.384 (3) to 1.389 (3) Å, which is in good agreement with the results of geometric studies of the BO₃ unit (Zobetz, 1982). Two of the three BO₃ groups exhibit 3m symmetry, and the third BO₃ group has m symmetry with O–B–O angles very close to 120°. The La³⁺ cations are 10-fold coordinated by oxygen atoms with La—O bond lengths ranging from 2.501 (2) to 2.812 (2) Å. The [LaO₁₀] polyhedra are connected to each other and to the borate groups by sharing corners and edges forming a three-dimensional network with channels running parallel to [001]. In these channels the Ca²⁺ cations are situated and are surrounded by eight oxygen atoms with Ca—O bond lengths ranging from 2.3139 (13) to 2.662 (3) Å (Table 1).

Related literature

For phase equilibria in the system La₂O₃—CaO—B₂O₃, see: Zhang et al. (2001a). For a previous structure analysis of Ca₃La₃(BO₃)₅ based on X-ray powder diffraction data, see: Zhang et al. (2001b). For non-linear optical (NLO) applications of borate crystals containing triangular BO₃ anions, see: Chen et al. (1999). For a review of the geometry of the BO₃ group, see: Zobetz (1982). Fo the potential applications of Ca₃La₃(BO₃)₅ for photoluminescence, see: Zhang et al. (2005); Han et al. (2007).

S2. Experimental

Single crystals of compound (I) were grown using a LiBO₂-containing flux. The composition of the mixture for crystal growth was 1:1:4:3 of CaCO₃ (Sinopharm Regent, AR), La₂O₃ (Materials, 99.8%), H₃BO₃ (Sinopharm Regent, 99.99%), and Li₂CO₃ (Sinopharm Reagent, AR). The 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 solified flux attached to the crystals was readily dissolved in water. Crystals with an average size of 0.5 mm and mostly rod shaped habit were obtained.

S3. Refinement

The present study confirms the basic structural features determined from the previous investigation by Zhang et al. (2001b) with a much higher precesion and with all displacement parameters refined anisotropically.

Computing details

Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear (Rigaku, 2000); data reduction: CrystalClear (Rigaku, 2000); 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).

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. Packing diagram of the structure of (I). [CaO8] polyhedra are yellow, [LaO10] polyhedra are blue and [BO3] units are green.

tricalcium trilanthanum pentakis(orthoborate)

Crystal data

Ca3La3(BO3)5	Dx = 4.492 Mg m^−3
Mr = 831.02	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P63mc	Cell parameters from 1909 reflections
Hall symbol: P 6c -2c	θ = 2.2–27.5°
a = 10.530 (3) Å	µ = 11.59 mm^−1
c = 6.398 (2) Å	T = 293 K
V = 614.4 (3) Å^3	Rod, colourless
Z = 2	0.22 × 0.12 × 0.10 mm
F(000) = 752

Data collection

Rigaku Mercury CCD diffractometer	534 independent reflections
Radiation source: Sealed Tube	534 reflections with I > 2σ(I)
Graphite Monochromator monochromator	Rint = 0.035
Detector resolution: 14.6306 pixels mm^-1	θmax = 27.5°, θmin = 2.2°
CCD_Profile_fitting scans	h = −13→13
Absorption correction: multi-scan (CrystalClear; Rigaku, 2000)	k = −13→13
Tmin = 0.206, Tmax = 0.304	l = −8→7
4065 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.02P)^2 + 1.5843P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.012	(Δ/σ)max < 0.001
wR(F^2) = 0.030	Δρmax = 0.41 e Å^−3
S = 0.89	Δρmin = −0.59 e Å^−3
534 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
53 parameters	Extinction coefficient: 0.0632 (12)
1 restraint	Absolute structure: Flack (1983), 236 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.03 (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
Ca1	0.47334 (5)	0.52666 (5)	0.76261 (15)	0.00673 (19)
La1	0.156065 (12)	0.843935 (12)	0.08229 (8)	0.00493 (11)
B1	0.1989 (3)	0.8011 (3)	0.5473 (8)	0.0049 (10)
B2	0	0	0.2435 (15)	0.0086 (17)
B3	0.6667	0.3333	0.598 (3)	0.0092 (19)
O1	0.6272 (3)	0.9278 (2)	0.4462 (4)	0.0067 (5)
O2	0.07534 (16)	0.92466 (16)	0.7399 (6)	0.0097 (7)
O3	0.59052 (16)	0.40948 (16)	0.5984 (8)	0.0083 (6)
O4	0.22657 (17)	0.77343 (17)	0.7443 (5)	0.0066 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca1	0.0060 (3)	0.0060 (3)	0.0073 (4)	0.0023 (3)	−0.0001 (2)	0.0001 (2)
La1	0.00442 (12)	0.00442 (12)	0.00474 (14)	0.00129 (9)	0.00003 (8)	−0.00003 (8)
B1	0.0052 (15)	0.0052 (15)	0.007 (3)	0.0044 (18)	−0.0006 (10)	0.0006 (10)
B2	0.011 (3)	0.011 (3)	0.003 (4)	0.0057 (13)	0	0
B3	0.009 (2)	0.009 (2)	0.009 (6)	0.0046 (11)	0	0
O1	0.0069 (10)	0.0056 (10)	0.0073 (11)	0.0029 (9)	−0.0014 (10)	0.0016 (9)
O2	0.0090 (12)	0.0090 (12)	0.0124 (16)	0.0055 (14)	−0.0005 (7)	0.0005 (7)
O3	0.0101 (10)	0.0101 (10)	0.0067 (17)	0.0065 (11)	0.0005 (9)	−0.0005 (9)
O4	0.0067 (11)	0.0067 (11)	0.0055 (16)	0.0026 (13)	−0.0014 (7)	0.0014 (7)

Geometric parameters (Å, º)

Ca1—O4^i	2.3139 (13)	La1—O1^i	2.678 (3)
Ca1—O4^ii	2.3139 (13)	La1—O3^xiv	2.8112 (8)
Ca1—O1^iii	2.376 (3)	La1—O3^xv	2.8112 (8)
Ca1—O1^iv	2.376 (3)	La1—B2^xvi	3.028 (3)
Ca1—O3	2.382 (4)	La1—B1	3.076 (5)
Ca1—O3^v	2.444 (5)	B1—O4	1.358 (6)
Ca1—O1^ii	2.662 (3)	B1—O1^i	1.384 (3)
Ca1—O1^vi	2.662 (3)	B1—O1^xiii	1.384 (3)
Ca1—B1^i	2.858 (4)	B1—Ca1^i	2.858 (4)
Ca1—B1^ii	2.858 (4)	B1—Ca1^ii	2.858 (4)
Ca1—Ca1^v	3.3435 (11)	B2—O2^xvii	1.374 (3)
Ca1—Ca1^vii	3.3435 (11)	B2—O2^xviii	1.374 (3)
La1—O1^viii	2.501 (2)	B2—O2^xix	1.374 (3)
La1—O1^ix	2.501 (2)	B2—La1^xx	3.028 (3)
La1—O4^x	2.516 (4)	B2—La1^i	3.028 (3)
La1—O2^x	2.639 (3)	B2—La1^xxi	3.028 (3)
La1—O2^xi	2.6639 (15)	B3—O3^xxii	1.389 (3)
La1—O2^xii	2.6639 (15)	B3—O3^xxiii	1.389 (3)
La1—O1^xiii	2.678 (3)	B3—O3	1.389 (3)
O4^i—Ca1—O4^ii	93.58 (15)	O1^ix—La1—O3^xiv	116.83 (10)
O4^i—Ca1—O1^iii	151.80 (11)	O4^x—La1—O3^xiv	64.52 (12)
O4^ii—Ca1—O1^iii	80.01 (9)	O2^x—La1—O3^xiv	122.29 (12)
O4^i—Ca1—O1^iv	80.01 (9)	O2^xi—La1—O3^xiv	155.42 (13)
O4^ii—Ca1—O1^iv	151.80 (11)	O2^xii—La1—O3^xiv	121.81 (10)
O1^iii—Ca1—O1^iv	92.72 (12)	O1^xiii—La1—O3^xiv	88.50 (10)
O4^i—Ca1—O3	126.18 (10)	O1^i—La1—O3^xiv	65.77 (12)
O4^ii—Ca1—O3	126.18 (10)	O1^viii—La1—O3^xv	116.83 (9)
O1^iii—Ca1—O3	77.64 (10)	O1^ix—La1—O3^xv	69.51 (8)
O1^iv—Ca1—O3	77.64 (10)	O4^x—La1—O3^xv	64.52 (12)
O4^i—Ca1—O3^v	73.69 (10)	O2^x—La1—O3^xv	122.29 (12)
O4^ii—Ca1—O3^v	73.69 (10)	O2^xi—La1—O3^xv	121.81 (10)
O1^iii—Ca1—O3^v	78.17 (9)	O2^xii—La1—O3^xv	155.42 (13)
O1^iv—Ca1—O3^v	78.17 (9)	O1^xiii—La1—O3^xv	65.77 (12)
O3—Ca1—O3^v	144.65 (19)	O1^i—La1—O3^xv	88.50 (10)
O4^i—Ca1—O1^ii	56.39 (9)	O3^xiv—La1—O3^xv	50.66 (12)
O4^ii—Ca1—O1^ii	112.85 (10)	O4—B1—O1^i	119.7 (2)
O1^iii—Ca1—O1^ii	151.00 (8)	O4—B1—O1^xiii	119.7 (2)
O1^iv—Ca1—O1^ii	86.53 (8)	O1^i—B1—O1^xiii	120.6 (4)
O3—Ca1—O1^ii	73.88 (10)	O2^xvii—B2—O2^xviii	120.00 (1)
O3^v—Ca1—O1^ii	129.62 (7)	O2^xvii—B2—O2^xix	120.00 (1)
O4^i—Ca1—O1^vi	112.85 (10)	O2^xviii—B2—O2^xix	120.00 (1)
O4^ii—Ca1—O1^vi	56.39 (9)	O3^xxii—B3—O3^xxiii	120.00 (1)
O1^iii—Ca1—O1^vi	86.53 (8)	O3^xxii—B3—O3	120.00 (1)
O1^iv—Ca1—O1^vi	151.00 (8)	O3^xxiii—B3—O3	120.00 (1)
O3—Ca1—O1^vi	73.88 (10)	B1^ii—O1—Ca1^xv	147.6 (3)
O3^v—Ca1—O1^vi	129.62 (7)	B1^ii—O1—La1^xxiv	114.0 (3)
O1^ii—Ca1—O1^vi	80.50 (11)	Ca1^xv—O1—La1^xxiv	94.81 (8)
O1^viii—La1—O1^ix	138.96 (12)	B1^ii—O1—Ca1^i	83.5 (2)
O1^viii—La1—O4^x	73.88 (6)	Ca1^xv—O1—Ca1^i	82.95 (8)
O1^ix—La1—O4^x	73.88 (6)	La1^xxiv—O1—Ca1^i	87.75 (8)
O1^viii—La1—O2^x	71.80 (6)	B1^ii—O1—La1^ii	92.9 (2)
O1^ix—La1—O2^x	71.80 (6)	Ca1^xv—O1—La1^ii	89.98 (9)
O4^x—La1—O2^x	64.64 (11)	La1^xxiv—O1—La1^ii	111.47 (9)
O1^viii—La1—O2^xi	121.07 (8)	Ca1^i—O1—La1^ii	160.08 (10)
O1^ix—La1—O2^xi	71.30 (9)	B2^xxv—O2—La1^xxvi	123.0 (5)
O4^x—La1—O2^xi	137.71 (9)	B2^xxv—O2—La1^xxvii	91.42 (19)
O2^x—La1—O2^xi	82.07 (7)	La1^xxvi—O2—La1^xxvii	107.69 (7)
O1^viii—La1—O2^xii	71.30 (9)	B2^xxv—O2—La1^xxviii	91.42 (19)
O1^ix—La1—O2^xii	121.07 (8)	La1^xxvi—O2—La1^xxviii	107.69 (7)
O4^x—La1—O2^xii	137.71 (9)	La1^xxvii—O2—La1^xxviii	135.45 (14)
O2^x—La1—O2^xii	82.07 (7)	B3—O3—Ca1	154.0 (8)
O2^xi—La1—O2^xii	53.07 (13)	B3—O3—Ca1^vii	118.3 (8)
O1^viii—La1—O1^xiii	137.03 (9)	Ca1—O3—Ca1^vii	87.71 (10)
O1^ix—La1—O1^xiii	83.72 (6)	B3—O3—La1^xxix	94.64 (7)
O4^x—La1—O1^xiii	129.92 (8)	Ca1—O3—La1^xxix	86.76 (7)
O2^x—La1—O1^xiii	146.79 (6)	Ca1^vii—O3—La1^xxix	85.94 (9)
O2^xi—La1—O1^xiii	68.76 (8)	B3—O3—La1^iii	94.64 (7)
O2^xii—La1—O1^xiii	92.23 (9)	Ca1—O3—La1^iii	86.76 (7)
O1^viii—La1—O1^i	83.72 (6)	Ca1^vii—O3—La1^iii	85.94 (9)
O1^ix—La1—O1^i	137.03 (9)	La1^xxix—O3—La1^iii	169.80 (13)
O4^x—La1—O1^i	129.92 (8)	B1—O4—Ca1^ii	98.91 (12)
O2^x—La1—O1^i	146.79 (6)	B1—O4—Ca1^i	98.91 (12)
O2^xi—La1—O1^i	92.23 (9)	Ca1^ii—O4—Ca1^i	145.78 (15)
O2^xii—La1—O1^i	68.76 (8)	B1—O4—La1^xxvi	127.4 (3)
O1^xiii—La1—O1^i	53.37 (10)	Ca1^ii—O4—La1^xxvi	96.00 (9)
O1^viii—La1—O3^xiv	69.51 (8)	Ca1^i—O4—La1^xxvi	96.00 (9)

Symmetry codes: (i) −y+1, x−y+1, z; (ii) −x+y, −x+1, z; (iii) x−y+1, x, z+1/2; (iv) −x+1, −x+y, z+1/2; (v) −x+1, −y+1, z+1/2; (vi) x, x−y+1, z; (vii) −x+1, −y+1, z−1/2; (viii) y−1, x, z−1/2; (ix) −x+1, −y+2, z−1/2; (x) x, y, z−1; (xi) x−y+1, x+1, z−1/2; (xii) y−1, −x+y, z−1/2; (xiii) −x+y, y, z; (xiv) x−y, x, z−1/2; (xv) y, −x+y+1, z−1/2; (xvi) x, y+1, z; (xvii) y−1, −x+y−1, z−1/2; (xviii) x−y+1, x, z−1/2; (xix) −x, −y+1, z−1/2; (xx) −x+y−1, −x, z; (xxi) x, y−1, z; (xxii) −x+y+1, −x+1, z; (xxiii) −y+1, x−y, z; (xxiv) −x+1, −y+2, z+1/2; (xxv) −x, −y+1, z+1/2; (xxvi) x, y, z+1; (xxvii) y−1, −x+y, z+1/2; (xxviii) x−y+1, x+1, z+1/2; (xxix) y, −x+y, z+1/2.