Reinvestigation of the Pb₂[B₅O₉]Br structure based on single-crystal data

The structure of the title pentaborate, [Pb₂(B₅O₉)Br] (dilead pentaborate bromide), known from powder data, has been refined based on single-crystal data (R = 0.034) and is discussed in terms of intercrossing anionic and cationic frameworks.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](O-B) = 0.019 Å
• R factor = 0.034
• wR factor = 0.080
• Data-to-parameter ratio = 29.2

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT220_ALERT_2_A Large Non-Solvent    O     Ueq(max)/Ueq(min) ...       5.67 Ratio

Author Response: low quality of U values due to the presence of Pb and Br, acentric space group, twinning, and pseudosymmetry...

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           31.00
           From the CIF: _reflns_number_total               2544
           Count of symmetry unique reflns         1488
           Completeness (_total/calc)            170.97%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1056
           Fraction of Friedel pairs measured     0.710
           Are heavy atom types Z>Si present          yes

   1 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   0 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 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

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Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Crystal Impact, 2000); software used to prepare material for publication: SHELXL97.

Dilead pentaborate bromide

Crystal data

[Pb2(B5O9)Br]	F(000) = 1184
Mr = 692.34	Dx = 5.341 Mg m^−3
Orthorhombic, Pnn2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2 -2n	Cell parameters from 4734 reflections
a = 11.4935 (19) Å	θ = 3.5–36.0°
b = 11.4717 (19) Å	µ = 43.73 mm^−1
c = 6.5297 (11) Å	T = 293 K
V = 860.9 (2) Å^3	Column, colourless
Z = 4	0.13 × 0.03 × 0.02 mm

Data collection

Stoe IPDS-II diffractometer	2544 independent reflections
Radiation source: fine-focus sealed tube	2429 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.068
Detector resolution: 150 pixels mm^-1	θmax = 31.0°, θmin = 3.6°
ω scans	h = −12→16
Absorption correction: numerical (XPREP in SHELXTL; Sheldrick, 1996).	k = −16→16
Tmin = 0.093, Tmax = 0.387	l = −8→9
7497 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0337P)^2 + 13.5461P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.034	(Δ/σ)max < 0.001
wR(F^2) = 0.080	Δρmax = 1.96 e Å^−3
S = 1.06	Δρmin = −2.13 e Å^−3
2544 reflections	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
87 parameters	Extinction coefficient: 0.00036 (10)
1 restraint	Absolute structure: Flack (1983), 1059 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.03 (2)

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 as pseudomerohedral (110) twin, twin ratio 31.2 (2)%. 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
Pb1	0.25762 (6)	0.04280 (6)	0.00433 (9)	0.01489 (12)
Pb2	0.02631 (6)	0.23505 (5)	−0.66205 (14)	0.01614 (13)
Br1	0.0000	0.0000	−0.9081 (5)	0.0289 (6)
Br2	0.0000	0.5000	−0.6476 (6)	0.0259 (5)
O1	0.2376 (8)	0.3135 (8)	−0.5784 (14)	0.0030 (16)*
O2	0.2084 (8)	0.4248 (8)	−0.173 (2)	0.0108 (16)*
O3	0.2717 (8)	0.2256 (9)	−0.2448 (16)	0.0079 (19)*
O4	0.0686 (11)	0.2753 (11)	−0.2398 (19)	0.017 (2)*
O5	0.2790 (9)	0.4487 (11)	−0.835 (2)	0.015 (2)*
O6	0.3827 (9)	0.2616 (9)	−0.8357 (17)	0.0092 (18)*
O7	0.1785 (8)	0.2698 (9)	−0.9231 (15)	0.0046 (16)*
O8	0.4168 (8)	0.2110 (9)	−0.4921 (18)	0.0090 (16)*
O9	0.2339 (9)	0.1103 (10)	−0.5577 (16)	0.0106 (19)*
B1	0.2706 (13)	0.3217 (14)	−0.795 (2)	0.008 (3)*
B2	0.1803 (13)	0.3009 (14)	−0.146 (3)	0.012 (3)*
B3	0.2864 (14)	0.2180 (15)	−0.460 (2)	0.010 (3)*
B4	0.4556 (13)	0.2354 (16)	−0.683 (3)	0.011 (3)*
B5	0.2513 (15)	0.4950 (14)	−0.019 (3)	0.009 (3)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pb1	0.0172 (2)	0.0170 (2)	0.0105 (2)	0.0011 (2)	0.0010 (2)	0.0004 (3)
Pb2	0.0187 (2)	0.0179 (2)	0.0118 (3)	−0.0013 (2)	0.0034 (3)	0.0000 (3)
Br1	0.0202 (12)	0.0154 (10)	0.0511 (19)	−0.0011 (10)	0.000	0.000
Br2	0.0188 (11)	0.0179 (10)	0.0411 (16)	0.0002 (8)	0.000	0.000

Geometric parameters (Å, º)

Pb1—O5^i	2.497 (13)	O1—Pb1^viii	2.686 (9)
Pb1—O2^i	2.534 (12)	B2—O2	1.468 (19)
Pb1—O3	2.659 (11)	B2—O3	1.504 (19)
Pb1—O1^i	2.686 (9)	B2—O4	1.450 (19)
Pb1—O7^ii	2.798 (10)	B2—O7^ii	1.50 (2)
Pb1—O9^ii	2.975 (11)	O2—Pb1^viii	2.534 (12)
Pb1—Br2^i	2.9977 (16)	B3—O1	1.453 (19)
Pb1—Br1^ii	3.0554 (10)	B3—O3	1.417 (19)
Pb1—O6^ii	3.076 (11)	B3—O8	1.516 (19)
Pb1—B5^i	3.160 (19)	B3—O9	1.52 (2)
Pb2—O7	2.475 (10)	B4—O4^x	1.358 (19)
Pb2—O8^iii	2.571 (11)	B4—O6	1.34 (2)
Pb2—O1	2.647 (9)	B4—O8	1.35 (2)
Pb2—O6^iv	2.695 (11)	B5—O2	1.38 (2)
Pb2—O4	2.838 (13)	B5—O5^ii	1.36 (2)
Pb2—O9	2.864 (11)	B5—O9^xi	1.358 (19)
Pb2—O3^iii	3.010 (10)	O3—Pb2^xii	3.010 (10)
Pb2—Br2	3.0559 (8)	O4—B4^iv	1.358 (19)
Pb2—B1	3.104 (15)	O5—B5^vi	1.36 (2)
Pb2—Br1	3.153 (2)	O5—Pb1^viii	2.497 (13)
Br1—Pb1^v	3.0554 (10)	O6—Pb2^x	2.695 (11)
Br1—Pb1^vi	3.0554 (10)	O6—Pb1^vi	3.076 (11)
Br1—Pb2^vii	3.1532 (19)	O7—B2^vi	1.50 (2)
Br2—Pb1^viii	2.9977 (16)	O7—Pb1^vi	2.798 (10)
Br2—Pb1^iii	2.9977 (16)	O8—Pb2^xii	2.571 (11)
Br2—Pb2^ix	3.0559 (8)	O9—B5^xiii	1.358 (19)
B1—O1	1.470 (18)	O9—Pb1^vi	2.975 (11)
B1—O5	1.48 (2)	B1—Pb1^viii	3.220 (16)
B1—O6	1.485 (18)	B4—Pb2^x	3.25 (2)
B1—O7	1.473 (18)	B5—Pb1^viii	3.160 (19)
O5^i—Pb1—O2^i	122.1 (4)	B2—O3—Pb1	98.6 (9)
O5^i—Pb1—O3	79.0 (4)	B3—O3—Pb2^xii	94.1 (8)
O2^i—Pb1—O3	157.0 (3)	B2—O3—Pb2^xii	121.1 (8)
O5^i—Pb1—O1^i	53.3 (3)	Pb1—O3—Pb2^xii	93.9 (3)
O2^i—Pb1—O1^i	68.9 (3)	B4^iv—O4—B2	138.5 (15)
O3—Pb1—O1^i	130.4 (3)	B4^iv—O4—Pb2	95.0 (11)
O5^i—Pb1—O7^ii	119.8 (3)	B2—O4—Pb2	126.4 (10)
O2^i—Pb1—O7^ii	114.0 (3)	B5^vi—O5—B1	121.5 (13)
O3—Pb1—O7^ii	52.4 (3)	B5^vi—O5—Pb1^viii	125.4 (10)
O1^i—Pb1—O7^ii	162.2 (3)	B1—O5—Pb1^viii	105.2 (9)
O5^i—Pb1—O9^ii	161.5 (3)	B4—O6—B1	121.0 (13)
O2^i—Pb1—O9^ii	49.8 (3)	B4—O6—Pb2^x	102.2 (9)
O3—Pb1—O9^ii	112.8 (3)	B1—O6—Pb2^x	131.6 (9)
O1^i—Pb1—O9^ii	116.8 (3)	B4—O6—Pb1^vi	111.3 (10)
O7^ii—Pb1—O9^ii	64.2 (3)	B1—O6—Pb1^vi	91.9 (8)
O5^i—Pb1—Br2^i	78.0 (3)	Pb2^x—O6—Pb1^vi	91.7 (3)
O2^i—Pb1—Br2^i	92.5 (2)	B1—O7—B2^vi	116.3 (11)
O3—Pb1—Br2^i	82.6 (2)	B1—O7—Pb2	100.6 (8)
O1^i—Pb1—Br2^i	75.76 (19)	B2^vi—O7—Pb2	135.8 (8)
O7^ii—Pb1—Br2^i	120.7 (2)	Pb1^viii—Br2—Pb2	94.66 (3)
O9^ii—Pb1—Br2^i	116.5 (2)	Pb1^iii—Br2—Pb2	86.52 (3)
O5^i—Pb1—Br1^ii	86.2 (3)	Pb1^viii—Br2—Pb2^ix	86.52 (3)
O2^i—Pb1—Br1^ii	84.7 (2)	Pb1^iii—Br2—Pb2^ix	94.66 (3)
O3—Pb1—Br1^ii	107.5 (2)	Pb2—Br2—Pb2^ix	176.46 (16)
O1^i—Pb1—Br1^ii	84.26 (19)	B3—O1—B1	117.5 (11)
O7^ii—Pb1—Br1^ii	78.6 (2)	B3—O1—Pb2	102.0 (8)
O9^ii—Pb1—Br1^ii	76.9 (2)	B1—O1—Pb2	93.4 (7)
Br2^i—Pb1—Br1^ii	159.43 (5)	B3—O1—Pb1^viii	128.5 (8)
O5^i—Pb1—O6^ii	137.1 (3)	B1—O1—Pb1^viii	97.2 (8)
O2^i—Pb1—O6^ii	94.7 (3)	Pb2—O1—Pb1^viii	113.1 (3)
O3—Pb1—O6^ii	62.3 (3)	B5—O2—B2	123.9 (14)
O1^i—Pb1—O6^ii	149.1 (3)	B5—O2—Pb1^viii	103.8 (9)
O7^ii—Pb1—O6^ii	48.3 (3)	B2—O2—Pb1^viii	130.6 (11)
O9^ii—Pb1—O6^ii	60.3 (3)	B3—O3—B2	122.8 (13)
Br2^i—Pb1—O6^ii	79.1 (2)	B3—O3—Pb1	124.4 (10)
Br1^ii—Pb1—O6^ii	121.4 (2)	B2—O3—Pb1	98.6 (9)
O5^i—Pb1—B5^i	142.3 (4)	B3—O3—Pb2^xii	94.1 (8)
O2^i—Pb1—B5^i	25.1 (4)	B2—O3—Pb2^xii	121.1 (8)
O3—Pb1—B5^i	137.8 (4)	Pb1—O3—Pb2^xii	93.9 (3)
O1^i—Pb1—B5^i	91.6 (4)	B4^iv—O4—B2	138.5 (15)
O7^ii—Pb1—B5^i	89.1 (4)	B4^iv—O4—Pb2	95.0 (11)
O9^ii—Pb1—B5^i	25.3 (4)	B2—O4—Pb2	126.4 (10)
Br2^i—Pb1—B5^i	109.1 (3)	B5^vi—O5—B1	121.5 (13)
Br1^ii—Pb1—B5^i	75.9 (3)	B5^vi—O5—Pb1^viii	125.4 (10)
O6^ii—Pb1—B5^i	79.8 (4)	B1—O5—Pb1^viii	105.2 (9)
O7—Pb2—O8^iii	74.3 (3)	B4—O6—B1	121.0 (13)
O7—Pb2—O1	55.9 (3)	B4—O6—Pb2^x	102.2 (9)
O8^iii—Pb2—O1	122.7 (3)	B1—O6—Pb2^x	131.6 (9)
O7—Pb2—O6^iv	167.2 (3)	B4—O6—Pb1^vi	111.3 (10)
O8^iii—Pb2—O6^iv	111.1 (3)	B1—O6—Pb1^vi	91.9 (8)
O1—Pb2—O6^iv	113.2 (3)	Pb2^x—O6—Pb1^vi	91.7 (3)
O7—Pb2—O4	121.4 (3)	B1—O7—B2^vi	116.3 (11)
O8^iii—Pb2—O4	149.2 (3)	B1—O7—Pb2	100.6 (8)
O1—Pb2—O4	65.6 (3)	B2^vi—O7—Pb2	135.8 (8)
O6^iv—Pb2—O4	48.3 (3)	B1—O7—Pb1^vi	103.8 (8)
O7—Pb2—O9	69.8 (3)	B2^vi—O7—Pb1^vi	93.0 (7)
O8^iii—Pb2—O9	136.7 (3)	Pb2—O7—Pb1^vi	101.3 (3)
O1—Pb2—O9	49.9 (3)	B4—O8—B3	116.3 (12)
O6^iv—Pb2—O9	109.2 (3)	B4—O8—Pb2^xii	124.1 (9)
O4—Pb2—O9	73.0 (4)	B3—O8—Pb2^xii	110.8 (8)
O7—Pb2—O3^iii	122.7 (3)	B5^xiii—O9—B3	131.8 (13)
O8^iii—Pb2—O3^iii	48.5 (3)	B5^xiii—O9—Pb2	129.5 (10)
O1—Pb2—O3^iii	151.4 (3)	B3—O9—Pb2	91.4 (8)
O6^iv—Pb2—O3^iii	62.9 (3)	B5^xiii—O9—Pb1^vi	85.0 (9)
O4—Pb2—O3^iii	108.5 (3)	B3—O9—Pb1^vi	125.5 (8)
O9—Pb2—O3^iii	158.0 (3)	Pb2—O9—Pb1^vi	88.7 (3)
O7—Pb2—Br2	86.1 (2)	O1—B1—O7	109.5 (11)
O8^iii—Pb2—Br2	74.8 (2)	O1—B1—O5	104.2 (12)
O1—Pb2—Br2	75.3 (2)	O7—B1—O5	110.3 (12)
O6^iv—Pb2—Br2	84.3 (2)	O1—B1—O6	111.4 (12)
O4—Pb2—Br2	79.9 (3)	O7—B1—O6	109.6 (12)
O9—Pb2—Br2	124.9 (2)	O5—B1—O6	111.7 (11)
O3^iii—Pb2—Br2	76.1 (2)	O1—B1—Pb2	58.3 (6)
O7—Pb2—B1	27.8 (4)	O7—B1—Pb2	51.6 (6)
O8^iii—Pb2—B1	97.5 (4)	O5—B1—Pb2	115.0 (9)
O1—Pb2—B1	28.2 (4)	O6—B1—Pb2	133.3 (9)
O6^iv—Pb2—B1	140.5 (4)	O1—B1—Pb1^viii	55.9 (6)
O4—Pb2—B1	93.8 (4)	O7—B1—Pb1^viii	126.2 (9)
O9—Pb2—B1	58.2 (4)	O5—B1—Pb1^viii	48.5 (7)
O3^iii—Pb2—B1	141.4 (4)	O6—B1—Pb1^viii	124.1 (9)
Br2—Pb2—B1	77.3 (3)	Pb2—B1—Pb1^viii	89.4 (4)
O7—Pb2—Br1	81.6 (2)	O4—B2—O2	109.9 (13)
O8^iii—Pb2—Br1	74.4 (2)	O4—B2—O7^ii	110.4 (12)
O1—Pb2—Br1	118.9 (2)	O2—B2—O7^ii	110.4 (14)
O6^iv—Pb2—Br1	110.9 (2)	O4—B2—O3	108.8 (13)
O4—Pb2—Br1	130.6 (3)	O2—B2—O3	110.5 (12)
O9—Pb2—Br1	76.9 (2)	O7^ii—B2—O3	106.7 (12)
O3^iii—Pb2—Br1	86.8 (2)	O4—B2—Pb1	100.7 (9)
Br2—Pb2—Br1	148.95 (10)	O2—B2—Pb1	149.2 (10)
B1—Pb2—Br1	102.6 (3)	O7^ii—B2—Pb1	59.5 (6)
Pb1^v—Br1—Pb1^vi	158.42 (14)	O3—B2—Pb1	54.2 (7)
Pb1^v—Br1—Pb2	109.01 (4)	O3—B3—O1	115.8 (13)
Pb1^vi—Br1—Pb2	82.24 (3)	O3—B3—O8	105.0 (12)
Pb1^v—Br1—Pb2^vii	82.24 (3)	O1—B3—O8	110.3 (12)
Pb1^vi—Br1—Pb2^vii	109.01 (4)	O3—B3—O9	114.8 (13)
Pb2—Br1—Pb2^vii	118.74 (11)	O1—B3—O9	103.7 (11)
Pb1^viii—Br2—Pb1^iii	141.35 (15)	O8—B3—O9	107.0 (11)
Pb1^viii—Br2—Pb2	94.66 (3)	O3—B3—Pb2	106.7 (9)
Pb1^iii—Br2—Pb2	86.52 (3)	O1—B3—Pb2	52.3 (6)
Pb1^viii—Br2—Pb2^ix	86.52 (3)	O8—B3—Pb2	148.2 (10)
Pb1^iii—Br2—Pb2^ix	94.66 (3)	O9—B3—Pb2	61.0 (7)
Pb2—Br2—Pb2^ix	176.46 (16)	O6—B4—O8	121.9 (13)
B3—O1—B1	117.5 (11)	O6—B4—O4^x	114.5 (17)
B3—O1—Pb2	102.0 (8)	O8—B4—O4^x	123.4 (16)
B1—O1—Pb2	93.4 (7)	O6—B4—Pb2^x	54.1 (9)
B3—O1—Pb1^viii	128.5 (8)	O8—B4—Pb2^x	172.2 (11)
B1—O1—Pb1^viii	97.2 (8)	O4^x—B4—Pb2^x	60.4 (10)
Pb2—O1—Pb1^viii	113.1 (3)	O5^ii—B5—O9^xi	121.1 (15)
B5—O2—B2	123.9 (14)	O5^ii—B5—O2	120.3 (14)
B5—O2—Pb1^viii	103.8 (9)	O9^xi—B5—O2	118.7 (15)
B2—O2—Pb1^viii	130.6 (11)	O5^ii—B5—Pb1^viii	162.0 (11)
B3—O3—B2	122.8 (13)	O9^xi—B5—Pb1^viii	69.7 (9)
B3—O3—Pb1	124.4 (10)	O2—B5—Pb1^viii	51.1 (8)

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