Lanthanum selenite, La₂(SeO₃)₃

Hydro­thermally prepared La₂(SeO₃)₃ contains a three-dimensional network of LaO₁₀ polyhedra [d_av(La-O) = 2.622 (3) Å] and SeO₃ pyramids [d_av(Se-O) = 1.691 (3) Å]. One of the SeO₃ pyramids is in a general position and the other has crystallographic m symmetry. There are pseudo-channels in the [010] direction which are probably associated with the Se^IV lone pairs.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SMART; program(s) used to refine structure: CRYSTALS (Watkin et al., 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and ATOMS (Shape Software, 1999); software used to prepare material for publication: CRYSTALS.

(I)

Crystal data

La2(SeO3)3	Dx = 5.17 Mg m^−3
Mr = 658.70	Melting point: not measured K
Orthorhombic, Pbnm	Mo Kα radiation, λ = 0.71073 Å
a = 7.0725 (5) Å	Cell parameters from 3360 reflections
b = 8.4187 (7) Å	θ = 1–30°
c = 14.2273 (11) Å	µ = 22.64 mm^−1
V = 847.1 (2) Å^3	T = 300 K
Z = 4	Plate, colourless
F(000) = 1152.00	0.10 × 0.10 × 0.03 mm

Data collection

Bruker SMART1000 CCD area detector diffractometer	1271 independent reflections
Radiation source: fine-focus sealed tube	1079 reflections with > 1.00σ(I)
Graphite monochromator	Rint = 0.05
area detector scans	θmax = 30.0°, θmin = 1.0°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −9→9
Tmin = 0.060, Tmax = 0.424	k = −11→11
7762 measured reflections	l = −19→19

Refinement

Refinement on F	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Chebychev polynomial with 3 parameters (Carruthers & Watkin, 1979) 0.377 0.275 0.230
R[F^2 > 2σ(F^2)] = 0.026	(Δ/σ)max = 0.00006
wR(F^2) = 0.029	Δρmax = 1.19 e Å^−3
S = 1.08	Δρmin = −1.06 e Å^−3
1079 reflections	Extinction correction: Larson, 1967
67 parameters	Extinction coefficient: 1.8 (8)
Primary atom site location: structure-invariant direct methods

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

	x	y	z	Uiso*/Ueq
La1	0.17967 (4)	0.19781 (3)	0.563817 (17)	0.0082
Se1	0.17978 (6)	0.45249 (5)	0.37470 (3)	0.0090
Se2	0.09153 (9)	−0.04481 (7)	0.7500	0.0101
O1	0.5323 (5)	0.1971 (4)	0.5962 (3)	0.0148
O2	−0.0898 (5)	0.3822 (4)	0.5784 (3)	0.0177
O3	−0.1505 (5)	0.0726 (4)	0.5407 (2)	0.0126
O4	0.2630 (5)	0.4408 (4)	0.6558 (2)	0.0128
O5	0.0656 (9)	0.1546 (6)	0.7500	0.0198

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
La1	0.00824 (14)	0.00632 (14)	0.01014 (14)	0.00013 (8)	−0.00040 (9)	0.00031 (7)
Se1	0.0097 (2)	0.00920 (19)	0.0080 (2)	−0.00048 (16)	0.00052 (14)	−0.00022 (14)
Se2	0.0112 (3)	0.0095 (3)	0.0096 (3)	−0.0010 (2)	0.0000	0.0000
O1	0.0079 (15)	0.0133 (14)	0.0231 (17)	0.0024 (12)	0.0014 (14)	−0.0012 (12)
O2	0.0140 (17)	0.0097 (15)	0.0294 (19)	0.0024 (12)	−0.0080 (14)	−0.0032 (14)
O3	0.0116 (15)	0.0111 (15)	0.0150 (14)	−0.0009 (11)	0.0047 (13)	−0.0016 (12)
O4	0.0171 (16)	0.0124 (15)	0.0090 (13)	−0.0015 (12)	−0.0033 (13)	0.0011 (12)
O5	0.026 (3)	0.013 (2)	0.021 (2)	0.005 (2)	0.0000	0.0000

Geometric parameters (Å, º)

La1—O1	2.536 (4)	La1—O4^iv	2.561 (3)
La1—O1^i	2.656 (4)	La1—O5	2.7928 (19)
La1—O2	2.467 (4)	Se1—O1^i	1.687 (3)
La1—O2^ii	2.684 (4)	Se1—O2^v	1.669 (4)
La1—O3	2.583 (4)	Se1—O3^ii	1.713 (3)
La1—O3^iii	2.727 (3)	Se2—O4^iv	1.694 (3)
La1—O3^ii	2.718 (3)	Se2—O4^vi	1.694 (3)
La1—O4	2.499 (3)	Se2—O5	1.689 (5)
O1—La1—O1^i	122.8 (1)	O2—La1—O5	77.22 (14)
O1—La1—O2	138.25 (11)	O2^ii—La1—O5	149.07 (14)
O1—La1—O2^ii	62.56 (12)	O3—La1—O5	78.84 (14)
O1—La1—O3	155.67 (11)	O3^iii—La1—O5	112.74 (13)
O1—La1—O3^iii	99.87 (11)	O3^ii—La1—O4	66.4 (1)
O1—La1—O3^ii	70.52 (11)	O3^ii—La1—O4^iv	144.12 (11)
O1—La1—O4	71.03 (11)	O4—La1—O4^iv	112.75 (11)
O1—La1—O4^iv	75.49 (11)	O3^ii—La1—O5	137.65 (13)
O1—La1—O5	96.40 (14)	O4—La1—O5	71.21 (13)
O1^i—La1—O2	63.86 (12)	O4^iv—La1—O5	56.71 (13)
O1^i—La1—O2^ii	71.07 (12)	O1^i—Se1—O2^v	106.79 (18)
O2—La1—O2^ii	133.67 (5)	O1^i—Se1—O3^ii	99.71 (17)
O1^i—La1—O3	70.85 (11)	O2^v—Se1—O3^ii	95.11 (17)
O2—La1—O3	64.47 (11)	O4^iv—Se2—O4^vi	104.6 (2)
O2^ii—La1—O3	110.52 (11)	O4^iv—Se2—O5	97.88 (17)
O1^i—La1—O3^iii	77.35 (11)	O4^vi—Se2—O5	97.88 (17)
O2—La1—O3^iii	120.85 (11)	La1—O1—La1^ii	103.26 (13)
O2^ii—La1—O3^iii	54.9 (1)	La1—O1—Se1^ii	130.87 (18)
O3—La1—O3^iii	61.41 (13)	La1^ii—O1—Se1^ii	102.50 (16)
O1^i—La1—O3^ii	57.8 (1)	La1—O2—La1^i	104.36 (13)
O2—La1—O3^ii	86.57 (12)	La1—O2—Se1^v	148.5 (2)
O2^ii—La1—O3^ii	59.85 (11)	La1^i—O2—Se1^v	106.19 (16)
O3—La1—O3^ii	128.31 (9)	La1—O3—La1^iii	118.59 (13)
O3^iii—La1—O3^ii	109.20 (11)	La1—O3—La1^i	100.31 (11)
O1^i—La1—O4	105.6 (1)	La1^iii—O3—La1^i	105.19 (12)
O2—La1—O4	67.85 (12)	La1—O3—Se1^i	126.46 (17)
O2^ii—La1—O4	117.19 (11)	La1^iii—O3—Se1^i	103.14 (15)
O3—La1—O4	127.87 (11)	La1^i—O3—Se1^i	99.35 (15)
O3^iii—La1—O4	170.69 (11)	La1—O4—La1^vii	117.47 (12)
O1^i—La1—O4^iv	141.4 (1)	La1—O4—Se2^vii	128.03 (17)
O2—La1—O4^iv	127.66 (12)	La1^vii—O4—Se2^vii	104.33 (15)
O2^ii—La1—O4^iv	94.42 (11)	La1—O5—La1^viii	143.1 (2)
O3—La1—O4^iv	82.16 (11)	La1—O5—Se2	95.63 (12)
O3^iii—La1—O4^iv	65.5 (1)	La1^viii—O5—Se2	95.63 (12)
O1^i—La1—O5	138.00 (14)

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