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Acta Cryst. (2008). E64, i29    [ doi:10.1107/S1600536808009914 ]

Dineodymium(III) ditungstate(VI), Nd2W2O9

P. Held and P. Becker

Abstract top

Single crystals of monoclinic Nd2W2O9 were obtained by growth from tungsten borate flux in an atmosphere of air. The crystal structure consists of chains of distorted [WO6] octahedra that run along the c axis of the structure, and of [NdO9] polyhedra that are connected via common faces and common edges to form a three-dimensional framework.

Comment top

The crystal structure of the title compound consists of two symmetrically non-equivalent Nd atoms that both are ninefold coordinated by oxygen. Nd - O bond lengths range from 2.377 (6) Å to 3.096 (7) Å for Nd1 and from 2.447 (7) Å to 2.743 (8) Å for Nd2. (The distance to the next nearest cation, W1 in case of Nd1 with distance Nd1 - W1 = 3.3885 (7) Å, W2 in case of Nd2 with distance Nd2 - W2 = 3.3800 (7) Å, is taken as the limit of the first oxygen coordination surrounding of Nd). The [NdO9] polyhedra can be described as distorted capped square antiprisms for both Nd atoms. The polyhedra of Nd1 are sharing edges, thus forming chains that run along the a-axis of the structure (Fig. 1). Parallel to the a-c plane of the structure these chains are linked by dimers of edge-sharing coordination polyhedra of Nd2 (groups [Nd2O16]). The polyhedra dimers of Nd2 and the polyhedra chains of Nd1 are connected via common faces (i.e. three common oxygen ligands) between a Nd2 polyhedron and a Nd1 polyhedron, and a common edge of the Nd2 polyhedron and an adjacent Nd1 polyhedron (for the atomic numbering scheme see Fig. 3). From this linkage sheets of [NdO9] polyhedra parallel to the a-c plane result (Fig. 1). Along the b-axis the sheets are stacked in parallel with a translation of c/2, and are connected by common edges of Nd1 and Nd2 polyhedra alternatingly to neighbouring polyhedra sheets on both sides. This connection scheme results in a three-dimensional framework of [NdO9] polyhedra with narrow channels along the c-axis, where tungsten atoms are located. Within the [NdO9] polyhedra sheets Nd1 - Nd2 distances as short as 3.7787 (9) Å occur (face sharing of [NdO9] polyhedra).

Between the [NdO9] polyhedra sheets chains of distorted [WO6] octahedra are running along the c-axis (see Fig. 1 and Fig. 2). The octahedra chains consist of pairs of edge-sharing [WO6] units, each pair combining an octahedron [W1 O6] and an octahedron [W2 O6]. The octahedra pairs are connected via common corners O9 to infinite chains. W—O bonds to bridging oxygen atoms are elongated with bond lengths ranging from 1.855 (7) Å to 2.202 (7) Å. All oxygen atoms are simultaneously ligands of neodymium and of tungsten.

Borisov & Klevtsova (1970) published the structure of Pr2W2O9, however, with rather large uncertainty of the oxygen positions. Nd2W2O9 turns out to be isomorphous to this compound, but it should be noted that in Pr2W2O9 the coordination of one of the Pr atoms was regarded as eightfold, only, while the other is ninefold coordinated, as both Nd atoms are in Nd2W2O9. Due to this, in Pr2W2O9 the Pr coordination polyhedra are not connected to sheets but only to stripes parallel to the a-c plane of the structure. The inclusion of nine oxygen atoms to the coordination surrounding of Nd1 in Nd2W2O9 is meaningful, both, with respect to the connection scheme of Nd coordination polyhedra and regarding the Nd - O distances, where a distinct gap between distances of the nine oxygen atoms included in the coordination polyhedron and distances of further oxygen atoms is seen. All further oxygen atoms have distances Nd1 - O equal or larger than 3.4694 Å, which is more than the shortest Nd—W distance.

After the discovery of fast oxygen ion conduction in La2Mo2O9 by Lacorre et al. (2000) interest in RE2M2O9 (RE = rare earth element, M = Mo, W) compounds renewed. For La compounds La2M2O9 (M = Mo, W) evidence for the occurrence of a high-temperature (space group P213) and a low-temperature modification (space group P21 for La2Mo2O9, space group P1 for La2W2O9), together with their structure determination was given by Goutenoire et al. (2000), Laligant et al. (2001) and Evans et al. (2005); a similar polymorphy had been already presumed earlier for Ce2W2O9 by Yoshimura et al. (1976). Recently, the compound Eu2W2O9 was mentioned to be isomorphous to Pr2W2O9 (and hence to Nd2W2O9) by Aruga et al. (2005).

Related literature top

For literature on related structures, see: Lacorre et al. (2000), Goutenoire et al. (2000) and Evans et al. (2005) for La2Mo2O9; Laligant et al. (2001) for La2W2O9; Yoshimura et al. (1976) for Ce2W2O9; Borisov & Klevtsova (1970) for Pr2W2O9; Aruga et al. (2005) for Eu2W2O9.

Experimental top

Light purple prismatic single crystals of Nd2W2O9 were obtained by growth from tungsten borate flux using a melt of composition Nd2O3: B2O3: WO3 = 22.5: 25: 52.5. An appropriate homogenized powder mixture of Nd2O3 (99.9%, Alfa Aesar), B2O3 (99.98% Alfa Aesar) and WO3 (99.8%, Alfa Aesar) was heated in a covered platinum crucible in air atmosphere to 1423 K and subsequently cooled at a rate of 3 K h-1 to 1173 K. Transparent single crystals of the title compound were separated mechanically from the tungsten borate flux.

Refinement top

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 > 2sigma(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.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA (Stoe & Cie, 2001); data reduction: X-AREA (Stoe & Cie, 2001); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ATOMS (Dowty, 2002); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Projection along [010] of a fraction of the crystal structure of Nd2W2O9, showing one sheet of [NdO9] polyhedra that lies parallel to the a-c plane, and one layer of isolated chains of alternately edge- and corner-sharing [WO6] octahedra. Large purple and violet spheres denote Nd1 and Nd2 atoms, respectively, smaller orange spheres denote W atoms. Oxygen atoms are indicated by the corners of the coordination polyhedra and are not drawn.
[Figure 2] Fig. 2. View of the structure of Nd2W2O9 along the a-axis, emphasizing the arrangement and mutual connection of [NdO9] polyhedra sheets that lie parallel to the a-c plane. Nd atoms are denoted by large purple and violet spheres. Tungsten atoms (marked with smaller orange spheres) occupy interstitial space between the sheets of Nd coordination polyhedra and are arranged in layers parallel to the a-c plane. Oxygen atoms are indicated by the corners of the coordination polyhedra and are not drawn.
[Figure 3] Fig. 3. Fraction of the structure of Nd2W2O9 with atomic numbering scheme (projection approximately along the a-axis). Coordination polyhedra are indicated as a guide for the eye. Atoms are drawn as 50% probability ellipsoids. (Symmetry codes: (iii) -x + 1, -y + 1, -z; (vii) x, -y + 3/2, z + 1/2; (ix) -x, -y + 1, -z; (x) -x + 1, y - 1/2, -z + 1/2; (xi) -x, y - 1/2, -z + 1/2; (xiv) x, -y + 1/2, z - 1/2; (xv) x, y, z + 1; (xvi) -x, -y + 1, -z + 1).
Dineodymium(III) ditungstate(VI) top
Crystal data top
Nd2W2O9F000 = 1360
Mr = 800.17Dx = 8.008 Mg m−3
Monoclinic, P21/cMo Kα radiation
λ = 0.71073 Å
a = 7.6501 (11) ÅCell parameters from 25 reflections
b = 9.8547 (10) Åθ = 20.1–27.6º
c = 9.2326 (13) ŵ = 49.96 mm−1
β = 107.538 (11)ºT = 290 (1) K
V = 663.69 (15) Å3Prism, light purple
Z = 40.25 × 0.15 × 0.13 mm
Data collection top
Stoe IPDSII
diffractometer		2330 independent reflections
Radiation source: fine-focus sealed tube2072 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.088
T = 290(1) Kθmax = 32.2º
ω and φ scansθmin = 2.8º
Absorption correction: numerical
[X-SHAPE (Stoe & Cie, 1999) and X-RED (Stoe & Cie, 2001)]		h = −11→11
Tmin = 0.080, Tmax = 0.469k = −14→14
15723 measured reflectionsl = −13→13
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: full  w = 1/[σ2(Fo2) + (0.0439P)2 + 16.1611P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.037(Δ/σ)max < 0.001
wR(F2) = 0.093Δρmax = 2.34 e Å−3
S = 1.09Δρmin = −1.62 e Å−3
2330 reflectionsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
119 parametersExtinction coefficient: 0.00391 (19)
Primary atom site location: structure-invariant direct methods
Crystal data top
Nd2W2O9V = 663.69 (15) Å3
Mr = 800.17Z = 4
Monoclinic, P21/cMo Kα
a = 7.6501 (11) ŵ = 49.96 mm−1
b = 9.8547 (10) ÅT = 290 (1) K
c = 9.2326 (13) Å0.25 × 0.15 × 0.13 mm
β = 107.538 (11)º
Data collection top
Stoe IPDSII
diffractometer		2330 independent reflections
Absorption correction: numerical
[X-SHAPE (Stoe & Cie, 1999) and X-RED (Stoe & Cie, 2001)]		2072 reflections with I > 2σ(I)
Tmin = 0.080, Tmax = 0.469Rint = 0.088
15723 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.037119 parameters
wR(F2) = 0.093  w = 1/[σ2(Fo2) + (0.0439P)2 + 16.1611P]
where P = (Fo2 + 2Fc2)/3
S = 1.09Δρmax = 2.34 e Å−3
2330 reflectionsΔρmin = −1.62 e Å−3
Special details top

Experimental. A suitable single-crystal was carefully selected under a polarizing microscope and mounted in a glass capillary. The scattering intensities were collected on an imaging plate diffractometer (IPDS II, Stoe & Cie) equipped with a fine focus sealed tube X-ray source (Mo Kα, λ = 0.71073 Å) operating at 50 kV and 30 mA. Intensity data for the title compound were collected at room temperature by ω-scans in 180 frames (0 < ω < 180°; φ = 0° and 90°, Δω = 2°, exposure time of 10 min) in the 2Θ range 2.29 to 59.53°. Structure solution and refinement were carried out using the programs SIR92 (Altomare et al., 1993) and SHELXL97 (Sheldrick, 2008). A numerical absorption correction (X-RED (Stoe & Cie, 2001) was applied after optimization of the crystal shape (X-SHAPE (Stoe & Cie, 1999)). The last cycles of refinement included atomic positions and anisotropic parameters for all atoms. The final difference maps were free of any chemically significant features. The refinement was based on F2 for ALL reflections.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
W10.57359 (5)0.72579 (4)−0.03462 (4)0.01073 (11)
W2−0.07053 (5)0.75136 (4)0.26320 (4)0.01058 (11)
Nd10.28098 (7)0.95544 (5)0.07401 (5)0.01298 (13)
Nd20.22931 (7)0.55245 (5)0.15396 (5)0.01243 (13)
O1−0.0113 (10)0.3795 (7)0.0941 (7)0.0131 (12)
O20.4920 (10)0.5969 (7)−0.1761 (7)0.0144 (12)
O30.7367 (9)0.8644 (7)0.1417 (7)0.0128 (12)
O40.7687 (10)0.6210 (8)0.0779 (8)0.0152 (13)
O50.0438 (10)0.5887 (7)0.3447 (8)0.0139 (12)
O60.0995 (10)0.7810 (7)0.1630 (8)0.0149 (13)
O70.4449 (9)0.8935 (6)−0.1077 (7)0.0109 (11)
O80.4091 (10)0.7091 (8)0.0739 (8)0.0147 (12)
O9−0.2605 (10)0.6904 (8)0.3610 (7)0.0143 (13)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
W10.01099 (18)0.01014 (18)0.01053 (17)0.00011 (11)0.00245 (12)0.00011 (11)
W20.01064 (18)0.01036 (17)0.01018 (17)0.00025 (11)0.00230 (12)0.00037 (11)
Nd10.0138 (2)0.0122 (2)0.0118 (2)−0.00143 (15)0.00216 (16)0.00027 (15)
Nd20.0124 (2)0.0116 (2)0.0123 (2)−0.00062 (15)0.00227 (16)0.00016 (15)
O10.016 (3)0.009 (3)0.011 (3)0.002 (2)−0.001 (2)0.003 (2)
O20.022 (3)0.010 (3)0.009 (3)−0.002 (2)0.001 (2)−0.003 (2)
O30.015 (3)0.011 (3)0.011 (3)0.006 (2)0.001 (2)0.001 (2)
O40.013 (3)0.017 (3)0.012 (3)0.006 (2)−0.001 (2)0.005 (2)
O50.018 (3)0.009 (3)0.012 (3)0.002 (2)0.001 (2)0.004 (2)
O60.013 (3)0.015 (3)0.019 (3)−0.004 (2)0.008 (2)0.004 (2)
O70.014 (3)0.006 (3)0.011 (3)0.002 (2)0.001 (2)0.002 (2)
O80.011 (3)0.019 (3)0.016 (3)−0.004 (2)0.007 (2)−0.001 (3)
O90.017 (3)0.015 (3)0.012 (3)0.001 (2)0.007 (2)0.002 (2)
Geometric parameters (Å, °) top
W1—O21.794 (7)Nd1—Nd2vi3.7787 (9)
W1—O81.837 (7)Nd1—Nd2viii3.9479 (9)
W1—O41.855 (7)Nd2—O82.331 (7)
W1—O71.938 (6)Nd2—O7vii2.379 (6)
W1—O9i1.990 (7)Nd2—O12.447 (7)
W1—O32.202 (7)Nd2—O62.473 (8)
W1—Nd1ii3.3885 (7)Nd2—O1ix2.485 (6)
W1—Nd2iii3.4651 (7)Nd2—O2iii2.548 (8)
W1—Nd13.5344 (7)Nd2—O52.598 (7)
W2—O1iv1.796 (6)Nd2—O3x2.601 (7)
W2—O61.833 (7)Nd2—O4iii2.743 (8)
W2—O51.872 (6)Nd2—W2xi3.3800 (7)
W2—O3v1.917 (6)Nd2—W1iii3.4651 (7)
W2—O92.020 (7)O1—W2xi1.796 (6)
W2—O4v2.196 (7)O1—Nd2ix2.485 (6)
W2—Nd2iv3.3800 (7)O2—Nd1vi2.439 (7)
W2—Nd23.3934 (7)O2—Nd2iii2.548 (8)
Nd1—O5vi2.377 (6)O3—W2xii1.917 (6)
Nd1—O9iv2.409 (8)O3—Nd2viii2.601 (7)
Nd1—O2vii2.439 (7)O3—Nd1ii2.641 (7)
Nd1—O72.455 (7)O4—W2xii2.196 (7)
Nd1—O62.499 (7)O4—Nd2iii2.743 (8)
Nd1—O7ii2.513 (7)O5—Nd1vii2.377 (6)
Nd1—O82.618 (8)O7—Nd2vi2.379 (6)
Nd1—O3ii2.641 (7)O7—Nd1ii2.513 (7)
Nd1—O5iv3.096 (7)O9—W1xiii1.990 (7)
Nd1—W1ii3.3885 (7)O9—Nd1xi2.409 (8)
O2—W1—O8100.9 (3)O8—Nd1—Nd2vi84.50 (16)
O2—W1—O493.3 (3)O3ii—Nd1—Nd2vi43.46 (15)
O8—W1—O4102.3 (3)W1ii—Nd1—Nd2vi81.091 (15)
O2—W1—O7108.8 (3)W1—Nd1—Nd2vi64.843 (14)
O8—W1—O784.6 (3)O5vi—Nd1—Nd2viii159.13 (18)
O4—W1—O7155.3 (3)O9iv—Nd1—Nd2viii74.28 (17)
O2—W1—O9i94.2 (3)O2vii—Nd1—Nd2viii38.63 (18)
O8—W1—O9i160.6 (3)O7—Nd1—Nd2viii84.99 (15)
O4—W1—O9i88.8 (3)O6—Nd1—Nd2viii118.17 (17)
O7—W1—O9i79.0 (3)O7ii—Nd1—Nd2viii35.06 (14)
O2—W1—O3166.6 (3)O8—Nd1—Nd2viii86.62 (16)
O8—W1—O388.9 (3)O3ii—Nd1—Nd2viii98.06 (15)
O4—W1—O375.5 (3)W1ii—Nd1—Nd2viii64.182 (13)
O7—W1—O381.0 (3)W1—Nd1—Nd2viii76.989 (16)
O9i—W1—O378.4 (3)Nd2vi—Nd1—Nd2viii116.337 (18)
O2—W1—Nd1ii129.2 (2)O8—Nd2—O7vii80.4 (2)
O8—W1—Nd1ii116.3 (2)O8—Nd2—O1149.9 (2)
O4—W1—Nd1ii110.0 (2)O7vii—Nd2—O1129.0 (2)
O7—W1—Nd1ii47.2 (2)O8—Nd2—O671.9 (3)
O9i—W1—Nd1ii44.4 (2)O7vii—Nd2—O686.5 (2)
O3—W1—Nd1ii51.18 (18)O1—Nd2—O6111.1 (2)
O2—W1—Nd2iii45.4 (2)O8—Nd2—O1ix79.9 (2)
O8—W1—Nd2iii122.5 (2)O7vii—Nd2—O1ix151.4 (2)
O4—W1—Nd2iii51.9 (2)O1—Nd2—O1ix74.3 (3)
O7—W1—Nd2iii142.0 (2)O6—Nd2—O1ix67.7 (2)
O9i—W1—Nd2iii76.8 (2)O8—Nd2—O2iii81.3 (3)
O3—W1—Nd2iii121.46 (17)O7vii—Nd2—O2iii74.0 (2)
Nd1ii—W1—Nd2iii120.734 (19)O1—Nd2—O2iii99.8 (2)
O2—W1—Nd1123.3 (2)O6—Nd2—O2iii149.1 (2)
O8—W1—Nd146.0 (2)O1ix—Nd2—O2iii122.9 (2)
O4—W1—Nd1132.0 (2)O8—Nd2—O5128.2 (2)
O7—W1—Nd141.7 (2)O7vii—Nd2—O573.2 (2)
O9i—W1—Nd1115.0 (2)O1—Nd2—O573.8 (2)
O3—W1—Nd170.08 (18)O6—Nd2—O562.9 (2)
Nd1ii—W1—Nd172.141 (17)O1ix—Nd2—O5103.6 (2)
Nd2iii—W1—Nd1166.031 (17)O2iii—Nd2—O5129.8 (2)
O1iv—W2—O696.6 (3)O8—Nd2—O3x139.7 (2)
O1iv—W2—O5106.8 (3)O7vii—Nd2—O3x66.3 (2)
O6—W2—O591.3 (3)O1—Nd2—O3x64.6 (2)
O1iv—W2—O3v93.3 (3)O6—Nd2—O3x125.3 (2)
O6—W2—O3v98.6 (3)O1ix—Nd2—O3x138.9 (2)
O5—W2—O3v156.4 (3)O2iii—Nd2—O3x68.4 (2)
O1iv—W2—O991.1 (3)O5—Nd2—O3x64.0 (2)
O6—W2—O9171.5 (3)O8—Nd2—O4iii91.3 (2)
O5—W2—O983.0 (3)O7vii—Nd2—O4iii134.1 (2)
O3v—W2—O984.5 (3)O1—Nd2—O4iii64.5 (2)
O1iv—W2—O4v166.5 (3)O6—Nd2—O4iii133.7 (2)
O6—W2—O4v90.9 (3)O1ix—Nd2—O4iii67.0 (2)
O5—W2—O4v84.0 (3)O2iii—Nd2—O4iii60.1 (2)
O3v—W2—O4v74.5 (3)O5—Nd2—O4iii138.4 (2)
O9—W2—O4v82.2 (3)O3x—Nd2—O4iii95.7 (2)
O1iv—W2—Nd2iv44.5 (2)O8—Nd2—W2xi160.01 (19)
O6—W2—Nd2iv109.4 (2)O7vii—Nd2—W2xi100.57 (16)
O5—W2—Nd2iv144.8 (2)O1—Nd2—W2xi30.95 (15)
O3v—W2—Nd2iv50.0 (2)O6—Nd2—W2xi128.07 (16)
O9—W2—Nd2iv78.7 (2)O1ix—Nd2—W2xi104.97 (16)
O4v—W2—Nd2iv122.34 (18)O2iii—Nd2—W2xi79.85 (16)
O1iv—W2—Nd2120.5 (2)O5—Nd2—W2xi70.14 (16)
O6—W2—Nd245.2 (2)O3x—Nd2—W2xi34.37 (14)
O5—W2—Nd249.4 (2)O4iii—Nd2—W2xi73.54 (16)
O3v—W2—Nd2129.1 (2)O8—Nd2—W2103.17 (19)
O9—W2—Nd2127.1 (2)O7vii—Nd2—W286.45 (16)
O4v—W2—Nd272.57 (19)O1—Nd2—W286.55 (17)
Nd2iv—W2—Nd2153.578 (17)O6—Nd2—W231.75 (16)
O5vi—Nd1—O9iv108.0 (2)O1ix—Nd2—W277.98 (17)
O5vi—Nd1—O2vii156.0 (2)O2iii—Nd2—W2159.08 (15)
O9iv—Nd1—O2vii92.4 (2)O5—Nd2—W233.16 (14)
O5vi—Nd1—O775.9 (2)O3x—Nd2—W297.17 (16)
O9iv—Nd1—O7119.6 (2)O4iii—Nd2—W2139.03 (14)
O2vii—Nd1—O7105.4 (2)W2xi—Nd2—W296.814 (16)
O5vi—Nd1—O679.4 (2)O8—Nd2—W1iii93.93 (19)
O9iv—Nd1—O6119.7 (2)O7vii—Nd2—W1iii102.97 (16)
O2vii—Nd1—O679.5 (2)O1—Nd2—W1iii75.32 (17)
O7—Nd1—O6120.2 (2)O6—Nd2—W1iii161.63 (17)
O5vi—Nd1—O7ii127.1 (2)O1ix—Nd2—W1iii98.99 (16)
O9iv—Nd1—O7ii60.9 (2)O2iii—Nd2—W1iii30.07 (15)
O2vii—Nd1—O7ii73.7 (2)O5—Nd2—W1iii134.69 (15)
O7—Nd1—O7ii69.7 (2)O3x—Nd2—W1iii73.07 (16)
O6—Nd1—O7ii153.1 (2)O4iii—Nd2—W1iii32.17 (14)
O5vi—Nd1—O890.9 (2)W2xi—Nd2—W1iii66.284 (15)
O9iv—Nd1—O8160.7 (2)W2—Nd2—W1iii161.709 (19)
O2vii—Nd1—O870.3 (2)W2xi—O1—Nd2104.6 (3)
O7—Nd1—O860.1 (2)W2xi—O1—Nd2ix148.7 (4)
O6—Nd1—O866.9 (2)Nd2—O1—Nd2ix105.7 (2)
O7ii—Nd1—O8104.5 (2)W1—O2—Nd1vi145.5 (4)
O5vi—Nd1—O3ii66.4 (2)W1—O2—Nd2iii104.6 (3)
O9iv—Nd1—O3ii63.2 (2)Nd1vi—O2—Nd2iii104.7 (3)
O2vii—Nd1—O3ii136.4 (2)W2xii—O3—W1103.7 (3)
O7—Nd1—O3ii64.7 (2)W2xii—O3—Nd2viii95.7 (2)
O6—Nd1—O3ii143.4 (2)W1—O3—Nd2viii152.7 (3)
O7ii—Nd1—O3ii63.0 (2)W2xii—O3—Nd1ii133.4 (3)
O8—Nd1—O3ii123.9 (2)W1—O3—Nd1ii88.3 (2)
O5vi—Nd1—W1ii105.15 (17)Nd2viii—O3—Nd1ii92.2 (2)
O9iv—Nd1—W1ii35.29 (17)W1—O4—W2xii106.1 (3)
O2vii—Nd1—W1ii98.77 (17)W1—O4—Nd2iii95.9 (3)
O7—Nd1—W1ii84.57 (15)W2xii—O4—Nd2iii147.0 (3)
O6—Nd1—W1ii154.94 (18)W2—O5—Nd1vii130.8 (4)
O7ii—Nd1—W1ii34.47 (14)W2—O5—Nd297.5 (3)
O8—Nd1—W1ii136.43 (15)Nd1vii—O5—Nd298.8 (3)
O3ii—Nd1—W1ii40.51 (15)W2—O6—Nd2103.0 (3)
O5vi—Nd1—W190.51 (18)W2—O6—Nd1145.6 (4)
O9iv—Nd1—W1141.30 (17)Nd2—O6—Nd1110.3 (3)
O2vii—Nd1—W180.66 (17)W1—O7—Nd2vi130.6 (3)
O7—Nd1—W131.71 (14)W1—O7—Nd1106.5 (3)
O6—Nd1—W196.60 (18)Nd2vi—O7—Nd1102.8 (2)
O7ii—Nd1—W180.69 (15)W1—O7—Nd1ii98.3 (3)
O8—Nd1—W130.35 (15)Nd2vi—O7—Nd1ii107.6 (2)
O3ii—Nd1—W196.28 (15)Nd1—O7—Nd1ii110.3 (2)
W1ii—Nd1—W1107.859 (18)W1—O8—Nd2143.0 (4)
O5vi—Nd1—Nd2vi42.80 (18)W1—O8—Nd1103.6 (3)
O9iv—Nd1—Nd2vi106.32 (16)Nd2—O8—Nd1110.9 (3)
O2vii—Nd1—Nd2vi143.23 (18)W1xiii—O9—W2138.0 (4)
O7—Nd1—Nd2vi37.87 (14)W1xiii—O9—Nd1xi100.3 (3)
O6—Nd1—Nd2vi115.25 (18)W2—O9—Nd1xi120.4 (3)
O7ii—Nd1—Nd2vi87.96 (15)
Symmetry codes: (i) x+1, −y+3/2, z−1/2; (ii) −x+1, −y+2, −z; (iii) −x+1, −y+1, −z; (iv) −x, y+1/2, −z+1/2; (v) x−1, y, z; (vi) x, −y+3/2, z−1/2; (vii) x, −y+3/2, z+1/2; (viii) −x+1, y+1/2, −z+1/2; (ix) −x, −y+1, −z; (x) −x+1, y−1/2, −z+1/2; (xi) −x, y−1/2, −z+1/2; (xii) x+1, y, z; (xiii) x−1, −y+3/2, z+1/2.
Acknowledgements top

This work was supported by the Deutsche Forschungsgemeinschaft (DFG) (grant No. BE 2147/6-1). The authors thank G. Meyer and I. Pantenburg from the Institute of Inorganic Chemistry of the University of Cologne for help with data collection.

references
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