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Penta­bismuth heptoxide bromide, Bi5O7Br, crystallizes in the space group Cmca. Its structure is compared with the closely related Ibca structure of α-Bi5O7I. The change in the space group is assumedly the result of a compromise between the different spatial needs of Br and I and the rigidity of the {3}[Bi, O] frameworks into which they are embedded. A detailed procedure for the synthesis of Bi5O7Br is given.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107049025/iz3029sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107049025/iz3029Isup2.hkl
Contains datablock I

Comment top

In the quasi-binary system Bi2O3–BiBr3, five well established compounds, BiOBr (1:1), Bi4O5Br2 (2.5:1), Bi24O31Br10 (3.1:1), Bi3O4Br (4:1) and Bi12O17Br2 (8.5:1), are known (see, for example, Oppermann et al., 1996). A sixth compound of composition Bi5O7Br (7:1) has been described by Ketterer & Krämer (1984). It was obtained by reaction of aqueous solutions of HBiBr4 and NaOH; details of the synthesis were not given. It should be noted that the compound could hitherto not be synthesized by ceramic methods (Ketterer, 1985; Oppermann et al., 1996). In the following, a procedure for the synthesis of Bi5O7Br from aqueous solutions will be presented in detail (see Experimental). Its structure (Fig. 1) has been determined and will, in the following, be compared with that of the closely related α-Bi5O7I (Eggenweiler et al., 2001).

Both structures contain a {3}[Bi, O] framework into which {1} double columns (`zigzag rows') of halogen atoms aligned parallel to [010] are embedded. The three-dimensional frameworks consist of {2}[BiO]+ sheets aligned parallel to (001), which are mutually connected by folded {1}[Bi4O8]4- ribbons aligned parallel to [010]. The `folded ribbon' (Fig. 2) description implies that Bi—O bonds of lengths greater than 3 Å (see below) are neglected.

Bond-distance ranges in Bi5O7Br are as found in other bismuth oxide bromides (see, for example, Keller et al., 2001) and (with respect to Bi—O) in α-Bi5O7I. Owing to the electron lone pair (Lp) of BiIII one can distinguish between `primary' and `secondary' Bi—X bonds (Alcock, 1972). The Bi—O bonds with lengths in the range 2.1–2.4 Å (3.2–3.3 Å) can be classified as primary (secondary), while those in the range 2.5–2.7 Å may play an intermediate role. The Bi—Br bond lengths (in the range 3.4–3.6 Å) can be assigned to secondary bonding (as in BiSBr; Keller & Krämer, 2006b). Another Bi···Br distance of 4.17 Å is clearly non-bonding. As usual for `ions' with an Lp, in all three cases (Bi1, Bi2 and Bi3) the atoms bonded by primary bonds occupy one side of the coordination sphere, while the other `ligand atoms' gather at the other side, i.e. that to which the Lp is pointing. In the context of the crystal structure, the LPs of all Bi atoms are directed into the space that is occupied by the halogen atoms. These latter findings also apply to the structure of α-Bi5O7I.

While the symmetries of Bi5O7Br and α-Bi5O7I are different (Cmca versus Ibca), their lattice constants differ only slightly (Δa = 0.18 Å, Δb = 0.05 Å and Δc = 0.00 Å). The similarity of the two structures becomes especially obvious when their two projections onto (010) are superimposed with a mutual z shift of 1/4 (Fig. 3). It is also reflected in the fact that the two space groups, Cmca and Ibca, have the common minimal supergroup Cmma (2c' = c). While the (010) projections are nearly identical, small differences in the `heights' of corresponding atoms occur [0.2 (2) Å for the Bi and halogen atoms], which lead to the most important structural difference (Fig. 2): with respect to their overall folding pattern, two of the aforesaid ribbons which are vicinal in the [100] direction appear to be `in phase' in the I compound, while there is a `phase shift' of π in the Br compound (all details accounted for, the two ribbons are related to one another by an a(001) operation in the I and an m(100) operation in the Br compound).

The similarity of the lattice constants shows that the three-dimensional [Bi, O] framework, held together by strong Bi—O bonds, hardly adjusts itself with respect to size when the Br atoms in Bi5O7Br are replaced by the larger I atoms. This is similar to the case of ABi6O9X compounds (A = Na, K and Rb, and X = Cl, Br and I), which also contain {3}[Bi, O] frameworks almost insensitive to changes in A and X (Keller & Krämer, 2006b, Keller et al., 2007). In contrast to these compounds, however, the experimental size difference between Br and I in Bi5O7X, as retrievable from the bond lengths, amounts to 0.18 Å (but see below), which is much closer to the `isotypic' size difference expectation value ρBr I of 0.22 Å (Keller & Krämer, 2006a) than the corresponding value of 0.05 Å in KBi6O9X (X = Br and I). A very similar size difference of 0.19 Å is found in BiOX (X = Br and I), the [Bi, O] substructure of which consists of the aforesaid {2} [BiO]+ building blocks only (Keller & Krämer, 2006b).

Similar to those in BiOX, the X coordination polyhedra in Bi5O7X are essentially one-sided, as is visible from Figs. 1 and 2. Thus, when I atoms are replaced by the smaller Br atoms, the latter can retreat to one side in the [001] direction, thereby enabling bonds I and II (Figs. 1 and 2) to shorten without a necessity for the [Bi, O] framework to change. Things are different in the [100] direction, where X—Bi bonds are equally present on both sides, such that the framework actually gives way to some extent (Δa = 0.18 Å). For [010], a special solution has been found; enabled by the different arrangement of the {1}[Bi4O8]4- ribbons, the distances between vicinal Br atoms in a Br column become alternating (in contrast to the I···I distances), such that the Br coordination polyhedron becomes partially one-sided also in the [010] direction, as visible from Fig. 2, thus allowing the remaining Bi—X bonds to shorten as well. Seen the other way around, it is presumably the difference in the spatial requirements of the halogen atoms which induces the re-arrangement of the ribbons (and – as a consequence – the change in space group).

It should be noted that, as the two Bi5O7X structures are not isotypic, the calculation of the experimental Br/I size difference is not unambiguous; the above value of 0.18 Å is rather an estimation. Firstly, to have the coordination numbers (CN) of Br and I both equal to 6 we have to neglect the two weak secondary I—Bi3 bonds IV (Fig. 2) of lengths 4.01 Å. The assignment of CN 8 to both X atoms would be an alternative, but it would imply the existence of two additional very long Br—Bi3 bonds of length 4.17 Å (see above) and the unreasonable assumption that these two Bi—X bonds elongate in the transition from I to Br. Secondly, while bonds I (X—Bi1) and II (X—Bi2) exist analogously in both compounds, the remaining two bonds III (X—Bi3), when seen from [001] (Fig. 2), have a cisoid (transoid) configuration for X = Br (I) owing to the different symmetries of the coordination polyhedra [m (2) for X = Br (I)]. This latter difference matters neither in the light of the bond valence nor in that of the ionic radii concept, however, as the connectivity schemes and X coordination numbers are identical for both compounds. On the other hand, the implied neglection of the two Bi—I bonds IV in this case means that the experimental size difference of 0.18 (6) Å (calculated from the six pairs of corresponding bonds) is presumably slightly overestimated.

Related literature top

For related literature, see: Alcock (1972); Eggenweiler et al. (2001); Keller & Krämer (2006a, 2006b); Keller et al. (2001, 2007); Ketterer (1985); Ketterer & Krämer (1984); Oppermann et al. (1996).

Experimental top

In a 100 ml polypropylene flask, distilled and freshly filtered water was added to NaOH (9.2 g, 0.23 mol) until the volume of the solution was 32 ml. The solution was heated to about 313 K from below but not stirred. Three 16.5 ml portions of a 0.0035 M filtered solution of Bi2O3 in 1.5 N aqueous HBr were added dropwise from a burette (approxemately one drop every 2 min), each portion at one of three successive days (partitioning helped to keep the dropping rate approximately constant). Colourless (sometimes slightly yellowish) needles of Bi5O7Br (with lengths of up to 1 mm) grew during the second and third day. The by-products were white amorphous `microflakes' and minor amounts of yellow Bi2O3, and colourless NaBi6O9Br crystals. The mother liquor and reaction products were filtered through a plastic sieve (pore size 70 µ, diameter 25 mm) to separate the Bi5O7Br needles from the by-products. Still in the sieve, the needles are washed about ten times with about 20 ml of water and dried (yield 80 mg, 65 µmol, 93%). Chemical analyses: Bi (AAS): 85.5% (theory 84.5%); Br (ion-selective electrode) 7.4% (theory 6.5%).

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SMART (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXD (Sheldrick, 2006); program(s) used to refine structure: SHELXTL (Bruker, 2000); molecular graphics: SCHAKAL 99 (Keller, 2004); software used to prepare material for publication: SHELXTL (Bruker, 2000).

Figures top
[Figure 1] Fig. 1. The structure of Bi5O7Br as seen from [010]. Bi, Br and O atoms are symbolized by small black, large (red in the online version of the journal) and medium-sized (light-blue online) spheres. Atoms/bonds in the `background' have been drawn paler. {3}[BiO]+ sheets (seen side-on) are emphasized. Secondary Bi—O bonds are not visualized. Symbols I, II, III and I' denote groups of Bi—X bonds (see text).
[Figure 2] Fig. 2. Parts of the structures of Bi5O7Br (above) and α-Bi5O7I (below) as seen from [001].
[Figure 3] Fig. 3. Superposition of the corresponding parts of the structures of Bi5O7Br and Bi5O7I (dashed lines).
pentabismuth heptoxide bromide top
Crystal data top
Bi5O7BrF(000) = 4048
Mr = 1236.81Dx = 8.376 Mg m3
Orthorhombic, CmcaMo Kα radiation, λ = 0.71073 Å
a = 16.087 (3) ŵ = 93.49 mm1
b = 5.2965 (10) ÅT = 293 K
c = 23.022 (4) ÅNeedle, colourless
V = 1961.6 (6) Å30.26 × 0.02 × 0.01 mm
Z = 8
Data collection top
Bruker SMART CCD area-detector
diffractometer
1251 independent reflections
Radiation source: fine-focus sealed tube789 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.080
phi and ω scansθmax = 28.9°, θmin = 1.8°
Absorption correction: integration
SHELXTL (Bruker, 2000)
h = 1920
Tmin = 0.043, Tmax = 0.553k = 77
5805 measured reflectionsl = 2630
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048 w = 1/[σ2(Fo2) + (0.0175P)2 + 171.1663P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.094(Δ/σ)max = 0.002
S = 1.08Δρmax = 3.78 e Å3
1251 reflectionsΔρmin = 3.21 e Å3
46 parametersExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.000022 (4)
Crystal data top
Bi5O7BrV = 1961.6 (6) Å3
Mr = 1236.81Z = 8
Orthorhombic, CmcaMo Kα radiation
a = 16.087 (3) ŵ = 93.49 mm1
b = 5.2965 (10) ÅT = 293 K
c = 23.022 (4) Å0.26 × 0.02 × 0.01 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
1251 independent reflections
Absorption correction: integration
SHELXTL (Bruker, 2000)
789 reflections with I > 2σ(I)
Tmin = 0.043, Tmax = 0.553Rint = 0.080
5805 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.094 w = 1/[σ2(Fo2) + (0.0175P)2 + 171.1663P]
where P = (Fo2 + 2Fc2)/3
S = 1.08Δρmax = 3.78 e Å3
1251 reflectionsΔρmin = 3.21 e Å3
46 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
Bi10.00000.7801 (3)0.30082 (5)0.0109 (3)
Bi20.17454 (5)0.29675 (18)0.31053 (4)0.0160 (3)
Bi30.16846 (6)0.72964 (16)0.43894 (3)0.0161 (3)
Br0.00000.3020 (9)0.40015 (18)0.0347 (10)
O10.0814 (9)0.520 (3)0.2541 (9)0.016 (4)*
O20.25000.506 (4)0.25000.008 (4)*
O30.2073 (10)0.348 (3)0.4477 (8)0.023 (4)*
O40.1822 (10)0.715 (3)0.3495 (7)0.019 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Bi10.0113 (6)0.0117 (7)0.0097 (5)0.0000.0000.0004 (5)
Bi20.0114 (4)0.0221 (5)0.0146 (4)0.0012 (4)0.0025 (4)0.0029 (4)
Bi30.0158 (5)0.0211 (5)0.0114 (4)0.0018 (4)0.0014 (4)0.0017 (3)
Br0.028 (2)0.045 (3)0.031 (2)0.0000.0000.0053 (19)
Geometric parameters (Å, º) top
Bi1—O1i2.219 (17)Br—Bi3iii3.643 (3)
Bi1—O1ii2.219 (17)Br—O4iii3.838 (16)
Bi1—O1iii2.184 (16)Br—O43.838 (16)
Bi1—O12.184 (16)Br—O1xii4.07 (2)
Bi1—O43.157 (17)Br—O1iv4.07 (2)
Bi1—O4iii3.157 (17)O1—Bi1iv2.219 (17)
Bi1—Br3.412 (5)O1—Bi2ii2.571 (17)
Bi1—Bi1iv3.5338 (16)O1—Brii4.07 (2)
Bi1—Bi1ii3.5338 (16)O1—Bi2ix4.362 (16)
Bi1—Brv3.588 (5)O1—Bi2iv4.374 (15)
Bi1—Bi2i3.8030 (12)O1—Bi1vii4.269 (15)
Bi1—Bi2ii3.8030 (12)O1—Bi1ii4.418 (15)
Bi2—O22.154 (11)O1—Bi2viii4.388 (15)
Bi2—O42.390 (16)O1—Bi2iii4.476 (16)
Bi2—O2iv2.407 (13)O2—Bi2ix2.154 (10)
Bi2—O12.309 (17)O2—Bi2ii2.407 (13)
Bi2—O1iv2.571 (17)O2—Bi2viii2.407 (13)
Bi2—O4vi2.511 (16)O2—Bi2iv4.184 (18)
Bi2—O4vii3.214 (16)O2—Bi2vi4.184 (18)
Bi2—O33.214 (18)O2—Bi1iv4.355 (6)
Bi2—Br3.485 (3)O2—Bi1xiii4.355 (6)
Bi2—Br3.485 (3)O2—Bi1xiv4.434 (7)
Bi2—Bi2viii3.5926 (12)O2—Bi2xv4.580 (19)
Bi2—Bi2vi3.5926 (12)O2—Bi2v4.580 (19)
Bi2—Bi2ix3.6961 (17)O3—Bi3vi2.105 (16)
Bi3—O42.074 (15)O3—Bi3x2.714 (18)
Bi3—O3viii2.105 (16)O3—Bi3vii3.340 (16)
Bi3—O32.125 (16)O3—Bi3xi3.976 (17)
Bi3—O3x2.714 (18)O3—Bi2viii4.386 (17)
Bi3—O3v3.340 (17)O3—Bi3xvi4.490 (17)
Bi3—Br3.643 (3)O3—Bi2vi4.703 (17)
Bi3—Br3.643 (3)O3—Bi3viii5.084 (16)
Bi3—Bi3x3.7177 (17)O3—Brxvii5.179 (17)
Bi3—Bi3viii3.7277 (13)O4—Bi2viii2.511 (16)
Bi3—Bi3vi3.7277 (13)O4—Bi2v3.214 (16)
Bi3—Bi3xi3.8513 (17)O4—Bi2ii3.711 (15)
Bi3—Bi2viii3.9044 (12)O4—Bi3vi4.076 (16)
Br—Bi2iii3.485 (3)O4—Bi3viii4.178 (15)
Br—O3iii3.518 (16)O4—Brv4.431 (17)
Br—O33.518 (16)O4—Bi2ix4.876 (16)
Br—Bi1vii3.588 (5)O4—Bi1iv5.085 (15)
O1i—Bi1—O1ii72.3 (8)Brii—O1—Br140.8 (4)
O1i—Bi1—O1iii74.2 (4)Bi1iv—O1—Bi2ix100.5 (5)
O1ii—Bi1—O1iii115.7 (3)Bi1—O1—Bi2ix151.5 (6)
O1i—Bi1—O1115.7 (3)Bi2—O1—Bi2ix57.9 (3)
O1ii—Bi1—O174.2 (4)Bi2ii—O1—Bi2ix55.4 (3)
O1iii—Bi1—O173.7 (8)Brii—O1—Bi2ix95.2 (4)
O1i—Bi1—O4144.4 (5)Br—O1—Bi2ix122.1 (4)
O1ii—Bi1—O473.6 (5)Bi1iv—O1—Bi2iv60.5 (3)
O1iii—Bi1—O4131.4 (5)Bi1—O1—Bi2iv157.7 (6)
O1—Bi1—O463.2 (5)Bi2—O1—Bi2iv61.4 (3)
O1i—Bi1—O4iii73.6 (5)Bi2ii—O1—Bi2iv95.9 (5)
O1ii—Bi1—O4iii144.4 (5)Brii—O1—Bi2iv97.8 (4)
O1iii—Bi1—O4iii63.2 (5)Br—O1—Bi2iv98.8 (3)
O1—Bi1—O4iii131.4 (5)Bi2ix—O1—Bi2iv48.56 (17)
O4—Bi1—O4iii136.4 (6)Bi1iv—O1—Bi1vii55.8 (3)
O1i—Bi1—Br143.8 (4)Bi1—O1—Bi1vii105.7 (6)
O1ii—Bi1—Br143.8 (4)Bi2—O1—Bi1vii65.6 (4)
O1iii—Bi1—Br82.1 (5)Bi2ii—O1—Bi1vii148.0 (6)
O1—Bi1—Br82.1 (5)Brii—O1—Bi1vii117.3 (4)
O4—Bi1—Br71.4 (3)Br—O1—Bi1vii52.5 (2)
O4iii—Bi1—Br71.4 (3)Bi2ix—O1—Bi1vii96.5 (3)
O1i—Bi1—Bi1iv93.0 (5)Bi2iv—O1—Bi1vii52.19 (17)
O1ii—Bi1—Bi1iv93.0 (5)Bi1iv—O1—Bi1ii100.6 (5)
O4—Bi1—Bi1iv98.8 (3)Bi1—O1—Bi1ii52.3 (3)
O4iii—Bi1—Bi1iv98.8 (3)Bi2—O1—Bi1ii145.1 (6)
Br—Bi1—Bi1iv83.55 (8)Bi2ii—O1—Bi1ii59.2 (3)
O1iii—Bi1—Bi1ii98.4 (5)Brii—O1—Bi1ii47.2 (2)
O1—Bi1—Bi1ii98.4 (5)Br—O1—Bi1ii115.4 (4)
O4—Bi1—Bi1ii108.5 (3)Bi2ix—O1—Bi1ii114.6 (4)
O4iii—Bi1—Bi1ii108.5 (3)Bi2iv—O1—Bi1ii143.3 (5)
Br—Bi1—Bi1ii179.37 (9)Bi1vii—O1—Bi1ii144.8 (4)
Bi1iv—Bi1—Bi1ii97.08 (6)Bi1iv—O1—Bi2viii152.6 (6)
O1i—Bi1—Brv85.5 (5)Bi1—O1—Bi2viii100.4 (5)
O1ii—Bi1—Brv85.5 (5)Bi2—O1—Bi2viii54.8 (3)
O1iii—Bi1—Brv143.1 (4)Bi2ii—O1—Bi2viii57.3 (3)
O1—Bi1—Brv143.1 (4)Brii—O1—Bi2viii115.1 (4)
O4—Bi1—Brv81.9 (3)Br—O1—Bi2viii98.5 (4)
O4iii—Bi1—Brv81.9 (3)Bi2ix—O1—Bi2viii52.13 (17)
Br—Bi1—Brv98.31 (11)Bi2iv—O1—Bi2viii95.0 (3)
Bi1iv—Bi1—Brv178.14 (8)Bi1vii—O1—Bi2viii120.4 (4)
Bi1ii—Bi1—Brv81.06 (7)Bi1ii—O1—Bi2viii92.6 (3)
O1ii—Bi1—Bi2i92.2 (5)Bi1iv—O1—Bi2iii58.1 (3)
O1—Bi1—Bi2i97.2 (5)Bi1—O1—Bi2iii58.1 (3)
O4—Bi1—Bi2i158.0 (3)Bi2—O1—Bi2iii107.4 (6)
O4iii—Bi1—Bi2i63.7 (3)Bi2ii—O1—Bi2iii148.7 (6)
Br—Bi1—Bi2i117.97 (5)Brii—O1—Bi2iii93.1 (3)
Bi1iv—Bi1—Bi2i64.60 (3)Br—O1—Bi2iii49.0 (2)
Bi1ii—Bi1—Bi2i62.37 (3)Bi2ix—O1—Bi2iii148.8 (4)
Brv—Bi1—Bi2i114.32 (5)Bi2iv—O1—Bi2iii100.5 (3)
O1i—Bi1—Bi2ii92.2 (5)Bi1vii—O1—Bi2iii53.30 (18)
O1iii—Bi1—Bi2ii97.2 (5)Bi1ii—O1—Bi2iii92.9 (3)
O4—Bi1—Bi2ii63.6 (3)Bi2viii—O1—Bi2iii145.6 (5)
O4iii—Bi1—Bi2ii158.0 (3)Bi2—O2—Bi2ix118.2 (9)
Br—Bi1—Bi2ii117.97 (5)Bi2—O2—Bi2ii114.80 (13)
Bi1iv—Bi1—Bi2ii64.60 (3)Bi2ix—O2—Bi2ii103.80 (12)
Bi1ii—Bi1—Bi2ii62.37 (3)Bi2—O2—Bi2viii103.81 (12)
Brv—Bi1—Bi2ii114.32 (5)Bi2ix—O2—Bi2viii114.80 (13)
Bi2i—Bi1—Bi2ii95.18 (4)Bi2ii—O2—Bi2viii100.3 (7)
O2—Bi2—O474.8 (6)Bi2—O2—Bi2iv65.9 (5)
O2—Bi2—O2iv70.74 (9)Bi2ix—O2—Bi2iv59.2 (4)
O4—Bi2—O2iv141.6 (5)Bi2ii—O2—Bi2iv103.6 (2)
O2—Bi2—O174.9 (4)Bi2viii—O2—Bi2iv156.1 (5)
O4—Bi2—O176.7 (6)Bi2—O2—Bi2vi59.2 (4)
O2iv—Bi2—O1109.2 (5)Bi2ix—O2—Bi2vi65.9 (5)
O2—Bi2—O1iv104.3 (5)Bi2ii—O2—Bi2vi156.1 (5)
O4—Bi2—O1iv140.8 (5)Bi2viii—O2—Bi2vi103.6 (2)
O2iv—Bi2—O1iv66.0 (4)Bi2iv—O2—Bi2vi52.4 (2)
O1—Bi2—O1iv65.7 (3)Bi2—O2—Bi1iv60.83 (13)
O2—Bi2—O4vi78.6 (4)Bi2ix—O2—Bi1iv101.9 (4)
O4—Bi2—O4vi88.8 (5)Bi2ii—O2—Bi1iv63.55 (8)
O2iv—Bi2—O4vi68.4 (4)Bi2viii—O2—Bi1iv142.8 (4)
O1—Bi2—O4vi152.3 (5)Bi2iv—O2—Bi1iv52.89 (15)
O1iv—Bi2—O4vi130.0 (5)Bi2vi—O2—Bi1iv96.4 (4)
O2—Bi2—O4vii130.7 (5)Bi2—O2—Bi1xiii101.9 (4)
O4—Bi2—O4vii141.4 (6)Bi2ix—O2—Bi1xiii60.83 (13)
O2iv—Bi2—O4vii61.8 (5)Bi2ii—O2—Bi1xiii142.8 (4)
O1—Bi2—O4vii132.3 (5)Bi2viii—O2—Bi1xiii63.55 (8)
O1iv—Bi2—O4vii68.7 (5)Bi2iv—O2—Bi1xiii96.4 (4)
O4vi—Bi2—O4vii72.5 (5)Bi2vi—O2—Bi1xiii52.89 (15)
O2—Bi2—O3120.0 (4)Bi1iv—O2—Bi1xiii148.2 (5)
O4—Bi2—O362.9 (5)Bi2—O2—Bi159.10 (17)
O2iv—Bi2—O3122.7 (3)Bi2ix—O2—Bi1148.3 (2)
O1—Bi2—O3128.0 (5)Bi2ii—O2—Bi159.02 (15)
O1iv—Bi2—O3135.4 (5)Bi2viii—O2—Bi195.4 (4)
O4vi—Bi2—O360.9 (5)Bi2iv—O2—Bi196.83 (17)
O4vii—Bi2—O378.5 (4)Bi2vi—O2—Bi1118.0 (3)
O2—Bi2—Br146.4 (4)Bi1iv—O2—Bi147.41 (2)
O4—Bi2—Br79.2 (4)Bi1xiii—O2—Bi1148.94 (6)
O2iv—Bi2—Br139.0 (4)Bi2—O2—Bi1xiv148.3 (2)
O1—Bi2—Br78.8 (5)Bi2ix—O2—Bi1xiv59.10 (17)
O1iv—Bi2—Br83.0 (4)Bi2ii—O2—Bi1xiv95.4 (4)
O4vi—Bi2—Br122.0 (4)Bi2viii—O2—Bi1xiv59.02 (15)
O4vii—Bi2—Br82.7 (3)Bi2iv—O2—Bi1xiv118.0 (3)
O3—Bi2—Br63.2 (3)Bi2vi—O2—Bi1xiv96.84 (17)
O2iv—Bi2—Bi2viii97.6 (3)Bi1iv—O2—Bi1xiv148.94 (6)
O1—Bi2—Bi2viii93.5 (4)Bi1xiii—O2—Bi1xiv47.41 (2)
O1iv—Bi2—Bi2viii144.5 (4)Bi1—O2—Bi1xiv141.7 (5)
O4vi—Bi2—Bi2viii60.5 (4)Bi2—O2—Bi2xv144.7 (6)
O4vii—Bi2—Bi2viii133.0 (3)Bi2ix—O2—Bi2xv97.1 (4)
O3—Bi2—Bi2viii80.0 (3)Bi2ii—O2—Bi2xv51.0 (3)
Br—Bi2—Bi2viii122.59 (8)Bi2viii—O2—Bi2xv57.1 (4)
O2—Bi2—Bi2vi89.9 (4)Bi2iv—O2—Bi2xv142.79 (3)
O4—Bi2—Bi2vi130.4 (4)Bi2vi—O2—Bi2xv147.71 (3)
O1—Bi2—Bi2vi144.7 (5)Bi1iv—O2—Bi2xv114.4 (3)
O1iv—Bi2—Bi2vi88.5 (3)Bi1xiii—O2—Bi2xv95.04 (19)
O4vi—Bi2—Bi2vi41.6 (4)Bi1—O2—Bi2xv91.2 (3)
O4vii—Bi2—Bi2vi42.8 (3)Bi1xiv—O2—Bi2xv51.63 (16)
O3—Bi2—Bi2vi87.2 (3)Bi2—O2—Bi2v97.1 (4)
Br—Bi2—Bi2vi123.39 (8)Bi2ix—O2—Bi2v144.7 (6)
Bi2viii—Bi2—Bi2vi94.98 (4)Bi2ii—O2—Bi2v57.1 (4)
O4—Bi2—Bi2ix104.4 (4)Bi2viii—O2—Bi2v51.0 (3)
O1—Bi2—Bi2ix90.1 (5)Bi2iv—O2—Bi2v147.71 (3)
O1iv—Bi2—Bi2ix86.9 (4)Bi2vi—O2—Bi2v142.79 (3)
O4vi—Bi2—Bi2ix70.5 (4)Bi1iv—O2—Bi2v95.04 (19)
O4vii—Bi2—Bi2ix100.7 (3)Bi1xiii—O2—Bi2v114.4 (3)
O3—Bi2—Bi2ix129.3 (3)Bi1—O2—Bi2v51.63 (16)
Br—Bi2—Bi2ix167.36 (7)Bi1xiv—O2—Bi2v91.2 (3)
Bi2viii—Bi2—Bi2ix63.65 (2)Bi2xv—O2—Bi2v47.6 (2)
Bi2vi—Bi2—Bi2ix63.65 (2)Bi3vi—O3—Bi3123.6 (8)
O4—Bi3—O3viii90.3 (7)Bi3vi—O3—Bi3x105.4 (7)
O4—Bi3—O391.5 (7)Bi3—O3—Bi3x99.7 (6)
O3viii—Bi3—O389.7 (4)Bi3vi—O3—Bi292.1 (6)
O4—Bi3—O3x157.6 (6)Bi3—O3—Bi286.5 (6)
O3viii—Bi3—O3x74.6 (7)Bi3x—O3—Bi2153.4 (6)
O3—Bi3—O3x72.4 (7)Bi3vi—O3—Bi3vii83.1 (5)
O4—Bi3—O3v94.5 (5)Bi3—O3—Bi3vii150.7 (7)
O3viii—Bi3—O3v61.6 (5)Bi3x—O3—Bi3vii82.3 (4)
O3—Bi3—O3v150.7 (7)Bi2—O3—Bi3vii80.0 (4)
O3x—Bi3—O3v92.7 (5)Bi3vi—O3—Br148.2 (7)
O4—Bi3—Br79.1 (4)Bi3—O3—Br76.0 (4)
O3viii—Bi3—Br156.2 (5)Bi3x—O3—Br94.1 (4)
O3—Bi3—Br69.5 (4)Bi2—O3—Br62.2 (3)
O3x—Bi3—Br108.2 (3)Bi3vii—O3—Br74.7 (3)
O3v—Bi3—Br139.8 (3)Bi3vi—O3—Bi3xi75.7 (5)
O4—Bi3—Bi3x136.6 (4)Bi3—O3—Bi3xi71.0 (4)
O3viii—Bi3—Bi3x97.0 (5)Bi3x—O3—Bi3xi64.5 (3)
O3—Bi3—Bi3x46.0 (5)Bi2—O3—Bi3xi140.8 (5)
O3v—Bi3—Bi3x126.6 (3)Bi3vii—O3—Bi3xi133.3 (5)
Br—Bi3—Bi3x77.21 (7)Br—O3—Bi3xi136.0 (5)
O4—Bi3—Bi3viii87.3 (4)Bi3vi—O3—Bi2viii71.4 (4)
O3viii—Bi3—Bi3viii28.4 (4)Bi3—O3—Bi2viii62.8 (4)
O3—Bi3—Bi3viii118.0 (4)Bi3x—O3—Bi2viii150.9 (6)
O3x—Bi3—Bi3viii86.9 (3)Bi2—O3—Bi2viii53.8 (3)
Br—Bi3—Bi3viii164.84 (7)Bi3vii—O3—Bi2viii124.7 (5)
Bi3x—Bi3—Bi3viii117.70 (2)Br—O3—Bi2viii102.9 (4)
O4—Bi3—Bi3vi84.1 (5)Bi3xi—O3—Bi2viii87.1 (3)
O3viii—Bi3—Bi3vi62.8 (4)Bi3vi—O3—Bi3xvi55.3 (4)
O3x—Bi3—Bi3vi74.4 (3)Bi3—O3—Bi3xvi146.5 (7)
O3v—Bi3—Bi3vi124.4 (3)Bi3x—O3—Bi3xvi56.0 (3)
Br—Bi3—Bi3vi94.69 (6)Bi2—O3—Bi3xvi125.9 (5)
Bi3x—Bi3—Bi3vi62.30 (2)Bi3vii—O3—Bi3xvi56.7 (2)
Bi3viii—Bi3—Bi3vi90.54 (4)Br—O3—Bi3xvi123.8 (4)
O3viii—Bi3—Bi2103.5 (5)Bi3xi—O3—Bi3xvi77.2 (3)
O3—Bi3—Bi259.0 (5)Bi2viii—O3—Bi3xvi126.5 (4)
O3x—Bi3—Bi2131.3 (4)Bi3vi—O3—Bi2vi50.7 (4)
O3v—Bi3—Bi2130.1 (3)Bi3—O3—Bi2vi130.2 (6)
Br—Bi3—Bi256.28 (6)Bi3x—O3—Bi2vi130.1 (5)
Bi3x—Bi3—Bi2101.33 (4)Bi2—O3—Bi2vi49.7 (2)
Bi3viii—Bi3—Bi2114.63 (3)Bi3vii—O3—Bi2vi55.0 (2)
Bi3vi—Bi3—Bi263.023 (16)Br—O3—Bi2vi97.5 (4)
O4—Bi3—Bi3xi130.9 (5)Bi3xi—O3—Bi2vi125.9 (4)
O3—Bi3—Bi3xi77.5 (5)Bi2viii—O3—Bi2vi71.2 (3)
O3v—Bi3—Bi3xi76.9 (3)Bi3xvi—O3—Bi2vi77.7 (3)
Br—Bi3—Bi3xi136.10 (7)Bi3vi—O3—Bi3viii84.0 (5)
Bi3x—Bi3—Bi3xi58.98 (3)Bi3x—O3—Bi3viii105.5 (5)
Bi3viii—Bi3—Bi3xi58.72 (3)Bi2—O3—Bi3viii95.9 (4)
Bi3vi—Bi3—Bi3xi63.92 (3)Bi3vii—O3—Bi3viii166.4 (5)
Bi2—Bi3—Bi3xi126.38 (4)Br—O3—Bi3viii115.1 (4)
O3viii—Bi3—Bi2viii55.3 (5)Bi3xi—O3—Bi3viii46.49 (17)
O3—Bi3—Bi2viii88.2 (5)Bi2viii—O3—Bi3viii45.83 (16)
O3x—Bi3—Bi2viii126.4 (3)Bi3xvi—O3—Bi3viii118.3 (3)
O3v—Bi3—Bi2viii80.5 (3)Bi2vi—O3—Bi3viii112.6 (3)
Br—Bi3—Bi2viii110.62 (6)Bi3vi—O3—Brxvii141.5 (7)
Bi3x—Bi3—Bi2viii129.21 (3)Bi3—O3—Brxvii62.3 (4)
Bi3viii—Bi3—Bi2viii58.67 (2)Bi2—O3—Brxvii126.1 (4)
Bi3vi—Bi3—Bi2viii67.01 (3)Bi3vii—O3—Brxvii105.8 (4)
Bi2—Bi3—Bi2viii56.00 (2)Br—O3—Brxvii68.0 (3)
Bi3xi—Bi3—Bi2viii96.14 (4)Bi3xi—O3—Brxvii71.2 (3)
Bi1—Br—Bi2iii66.99 (7)Bi2viii—O3—Brxvii124.9 (4)
Bi1—Br—Bi266.99 (7)Bi3xvi—O3—Brxvii97.9 (3)
Bi2iii—Br—Bi2107.37 (11)Bi2vi—O3—Brxvii159.5 (4)
Bi1—Br—O3iii99.1 (3)Bi3viii—O3—Brxvii87.2 (3)
Bi2iii—Br—O3iii54.6 (3)Bi3—O4—Bi2113.7 (7)
Bi2—Br—O3iii161.6 (3)Bi3—O4—Bi2viii116.5 (7)
Bi1—Br—O399.1 (3)Bi2—O4—Bi2viii94.2 (6)
Bi2iii—Br—O3161.6 (3)Bi3—O4—Bi1104.4 (6)
Bi2—Br—O354.6 (3)Bi2—O4—Bi185.5 (5)
O3iii—Br—O3142.8 (6)Bi2viii—O4—Bi1135.0 (6)
Bi1—Br—Bi1vii98.31 (11)Bi3—O4—Bi2v103.6 (6)
Bi2iii—Br—Bi1vii67.44 (7)Bi2—O4—Bi2v141.4 (6)
Bi2—Br—Bi1vii67.44 (7)Bi2viii—O4—Bi2v76.7 (4)
O3iii—Br—Bi1vii104.6 (3)Bi1—O4—Bi2v76.1 (4)
O3—Br—Bi1vii104.6 (3)Bi3—O4—Bi2ii168.0 (7)
Bi1—Br—Bi3iii72.72 (8)Bi2—O4—Bi2ii74.6 (4)
Bi2iii—Br—Bi3iii63.30 (4)Bi2viii—O4—Bi2ii69.9 (3)
Bi2—Br—Bi3iii138.55 (14)Bi1—O4—Bi2ii66.7 (3)
O3—Br—Bi3iii125.9 (3)Bi2v—O4—Bi2ii67.0 (3)
Bi1vii—Br—Bi3iii129.44 (6)Bi3—O4—Br68.8 (4)
Bi1—Br—Bi372.72 (8)Bi2—O4—Br63.1 (3)
Bi2iii—Br—Bi3138.55 (14)Bi2viii—O4—Br155.3 (6)
Bi2—Br—Bi363.30 (4)Bi1—O4—Br57.4 (3)
O3iii—Br—Bi3125.9 (3)Bi2v—O4—Br127.0 (5)
Bi1vii—Br—Bi3129.44 (6)Bi2ii—O4—Br110.1 (4)
Bi3iii—Br—Bi396.13 (12)Bi3—O4—Bi3vi65.5 (4)
Bi1—Br—O4iii51.2 (2)Bi2—O4—Bi3vi68.7 (4)
Bi2—Br—O4iii116.1 (3)Bi2viii—O4—Bi3vi75.4 (4)
O3iii—Br—O4iii48.0 (4)Bi1—O4—Bi3vi142.7 (5)
O3—Br—O4iii141.2 (4)Bi2v—O4—Bi3vi140.2 (5)
Bi1vii—Br—O4iii104.2 (2)Bi2ii—O4—Bi3vi126.5 (4)
Bi3—Br—O4iii106.8 (3)Br—O4—Bi3vi86.4 (3)
Bi1—Br—O451.2 (2)Bi3—O4—Bi3viii63.0 (4)
Bi2iii—Br—O4116.1 (3)Bi2—O4—Bi3viii145.0 (6)
O3iii—Br—O4141.2 (4)Bi2viii—O4—Bi3viii62.3 (3)
O3—Br—O448.0 (4)Bi1—O4—Bi3viii129.6 (5)
Bi1vii—Br—O4104.2 (2)Bi2v—O4—Bi3viii62.2 (3)
Bi3iii—Br—O4106.8 (3)Bi2ii—O4—Bi3viii115.6 (4)
O4iii—Br—O499.6 (5)Br—O4—Bi3viii131.4 (4)
Bi1—Br—O1xii71.8 (2)Bi3vi—O4—Bi3viii79.8 (3)
Bi2—Br—O1xii74.9 (2)Bi3—O4—Brv68.9 (4)
O3iii—Br—O1xii89.6 (4)Bi2—O4—Brv135.6 (6)
O3—Br—O1xii127.0 (4)Bi2viii—O4—Brv125.4 (5)
Bi3iii—Br—O1xii101.7 (2)Bi1—O4—Brv53.3 (2)
Bi3—Br—O1xii133.0 (3)Bi2v—O4—Brv51.3 (2)
O4iii—Br—O1xii72.4 (3)Bi2ii—O4—Brv99.0 (4)
O4—Br—O1xii100.9 (3)Br—O4—Brv79.3 (3)
Bi1—Br—O1iv71.8 (2)Bi3vi—O4—Brv134.4 (4)
Bi2iii—Br—O1iv74.9 (2)Bi3viii—O4—Brv78.0 (3)
O3iii—Br—O1iv127.0 (4)Bi3—O4—Bi2ix144.9 (6)
O3—Br—O1iv89.6 (4)Bi2—O4—Bi2ix47.2 (3)
Bi3iii—Br—O1iv133.0 (2)Bi2viii—O4—Bi2ix51.3 (3)
Bi3—Br—O1iv101.7 (2)Bi1—O4—Bi2ix102.8 (4)
O4iii—Br—O1iv100.9 (3)Bi2v—O4—Bi2ix104.1 (4)
O4—Br—O1iv72.4 (3)Bi2ii—O4—Bi2ix47.09 (18)
Bi1iv—O1—Bi1106.7 (6)Br—O4—Bi2ix109.4 (3)
Bi1iv—O1—Bi2114.2 (6)Bi3vi—O4—Bi2ix79.5 (3)
Bi1—O1—Bi2115.8 (9)Bi3viii—O4—Bi2ix113.4 (3)
Bi1iv—O1—Bi2ii109.9 (8)Brv—O4—Bi2ix146.1 (4)
Bi1—O1—Bi2ii106.0 (6)Bi3—O4—Bi1iv129.2 (6)
Bi2—O1—Bi2ii103.8 (6)Bi2viii—O4—Bi1iv111.4 (4)
Bi1iv—O1—Brii61.5 (5)Bi2v—O4—Bi1iv102.9 (4)
Bi1—O1—Brii90.3 (5)Bi2ii—O4—Bi1iv50.11 (19)
Bi2—O1—Brii152.6 (7)Br—O4—Bi1iv60.6 (2)
Bi2ii—O1—Brii58.2 (4)Bi3vi—O4—Bi1iv113.5 (3)
Bi1iv—O1—Br97.3 (5)Bi3viii—O4—Bi1iv164.2 (4)
Bi1—O1—Br63.1 (5)Brv—O4—Bi1iv96.6 (3)
Bi2—O1—Br64.5 (5)Bi2ix—O4—Bi1iv63.45 (18)
Bi2ii—O1—Br152.7 (6)
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x, y+1/2, z+1/2; (iii) x, y, z; (iv) x, y1/2, z+1/2; (v) x, y+1, z; (vi) x+1/2, y1/2, z; (vii) x, y1, z; (viii) x+1/2, y+1/2, z; (ix) x+1/2, y, z+1/2; (x) x, y+1, z+1; (xi) x+1/2, y+3/2, z+1; (xii) x, y1/2, z+1/2; (xiii) x+1/2, y1/2, z; (xiv) x+1/2, y, z+1/2; (xv) x+1/2, y+1, z+1/2; (xvi) x+1/2, y+1/2, z+1; (xvii) x, y+1, z+1.

Experimental details

Crystal data
Chemical formulaBi5O7Br
Mr1236.81
Crystal system, space groupOrthorhombic, Cmca
Temperature (K)293
a, b, c (Å)16.087 (3), 5.2965 (10), 23.022 (4)
V3)1961.6 (6)
Z8
Radiation typeMo Kα
µ (mm1)93.49
Crystal size (mm)0.26 × 0.02 × 0.01
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionIntegration
SHELXTL (Bruker, 2000)
Tmin, Tmax0.043, 0.553
No. of measured, independent and
observed [I > 2σ(I)] reflections
5805, 1251, 789
Rint0.080
(sin θ/λ)max1)0.679
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.094, 1.08
No. of reflections1251
No. of parameters46
w = 1/[σ2(Fo2) + (0.0175P)2 + 171.1663P]
where P = (Fo2 + 2Fc2)/3
Δρmax, Δρmin (e Å3)3.78, 3.21

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXD (Sheldrick, 2006), SHELXTL (Bruker, 2000), SCHAKAL 99 (Keller, 2004).

Selected bond lengths (Å) top
Bi1—O1i2.219 (17)Bi2—O4v2.511 (16)
Bi1—O1ii2.184 (16)Bi2—O4vi3.214 (16)
Bi1—O43.157 (17)Bi2—O33.214 (18)
Bi1—Br3.412 (5)Bi2—Br3.485 (3)
Bi1—Briii3.588 (5)Bi3—O42.074 (15)
Bi2—O22.154 (11)Bi3—O3vii2.105 (16)
Bi2—O42.390 (16)Bi3—O32.125 (16)
Bi2—O2iv2.407 (13)Bi3—O3viii2.714 (18)
Bi2—O12.309 (17)Bi3—O3iii3.340 (17)
Bi2—O1iv2.571 (17)Bi3—Br3.643 (3)
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x, y, z; (iii) x, y+1, z; (iv) x, y1/2, z+1/2; (v) x+1/2, y1/2, z; (vi) x, y1, z; (vii) x+1/2, y+1/2, z; (viii) x, y+1, z+1.
 

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