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Acta Crystallogr Sect E Struct Rep Online. 2008 January 1; 64(Pt 1): i6.
Published online 2007 December 21. doi:  10.1107/S1600536807066962
PMCID: PMC2914884

Reinvestigation of tris­odium dihydroxido­tetra­oxidoneptunate(VII) dihydrate

Abstract

The title compound, Na3[NpO4(OH)2]·2H2O, contains distorted tetra­gonal–bipyramidal centrosymmetric [NpO4(OH)2]3− complex anions. The Np—O distances are 1.8975 (7) and 1.8891 (7) Å in the NpO4 group and 2.3451 (7) Å to the OH group. Both Na atoms (one in a general position, the second in a special position on an inversion centre) have a distorted octahedral oxygen environment.

Related literature

The structure of Na3[NpO4(OH)2]·2H2O was investigated by photographic technique with visual estimation of reflection intensities by Tomilin et al. (1981a [triangle]). Several other NpVII compounds containing [NpO4(OH)2]3− anions have been studied by photographic techniques, viz. Na3[NpO4(OH)2] (Tomilin et al., 1981b [triangle]), Na3[NpO4(OH)2]·4H2O (Tomilin et al., 1981c [triangle]), K3[NpO4(OH)2]·2H2O (Tomilin et al., 1983 [triangle]). Diffractometric structure determinations have been made for [Co(NH3)6][NpO4(OH)2]·2H2O (Grigor’ev et al., 1986 [triangle]), Cs3[NpO4(OH)2]·3H2O (Grigor’ev et al., 1993 [triangle]), K3[NpO4(OH)2]·2H2O (Charushnikova et al., 2007 [triangle]) and Na3[NpO4(OH)2] (Grigoriev & Krot, 2007 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-000i6-scheme1.jpg

Experimental

Crystal data

  • Na3[NpO4(OH)2]·2H2O
  • M r = 440.02
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-000i6-efi1.jpg
  • a = 7.8166 (3) Å
  • b = 7.7703 (2) Å
  • c = 6.8211 (2) Å
  • β = 112.9139 (14)°
  • V = 381.60 (2) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 13.79 mm−1
  • T = 100 (2) K
  • 0.12 × 0.08 × 0.02 mm

Data collection

  • Bruker Kappa APEXII area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2004 [triangle]) T min = 0.522, T max = 0.770
  • 16264 measured reflections
  • 2357 independent reflections
  • 1920 reflections with I > 2σ(I)
  • R int = 0.024

Refinement

  • R[F 2 > 2σ(F 2)] = 0.010
  • wR(F 2) = 0.021
  • S = 1.04
  • 2357 reflections
  • 70 parameters
  • 3 restraints
  • All H-atom parameters refined
  • Δρmax = 0.75 e Å−3
  • Δρmin = −0.88 e Å−3

Data collection: APEX2 (Bruker, 2006 [triangle]); cell refinement: SAINT-Plus (Bruker, 1998 [triangle]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a [triangle]); molecular graphics: SHELXTL97 (Sheldrick, 1997b [triangle]); software used to prepare material for publication: SHELXTL97.

Table 1
Selected geometric parameters (Å, °)
Table 2
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536807066962/sg2217sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807066962/sg2217Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

The title compound, (I) (Fig. 1), contains centrosymmetric complex anions [NpO4(OH)2]3- which are distorted tetragonal bipyramidal. The main bond lengths and angles in this anion are given in Table 1. The Np—O distances in the NpO4 group are close to the values 1.8981 (13) and 1.9012 (12) Å found in Na3[NpO4(OH)2] (Grigoriev & Krot, 2007). The Np—O distance to the OH group is a little longer than 2.3145 (11) Å in Na3[NpO4(OH)2].

Principal features of structure are the same as described by Tomilin et al. (1981a).

The Na1 atom occupies a special position on an inversion centre and has a distorted octahedral oxygen environment formed by six O atoms of two [NpO4(OH)2]3- anions. The Na1 atoms and [NpO4(OH)2]3- anions form columns along the [001] direction, the layers of the columns are parallel to the (100) plane (Fig. 2). The Na2 atoms and crystallization water molecules occupy general positions between the layers. The Na2 atom has a distorted octahedral oxygen environment formed by O atoms of [NpO4(OH)2]3- anions and water molecules.

The OH group acts as proton donor in a hydrogen bond with an O atom of NpO4 group of a neighbouring anion (Table 2). This hydrogen bond is stronger than the bond formed by OH group in Na3[NpO4(OH)2] [the O···O distance 3.0255 (17)]. Such a difference can be one of the reasons for the elongation of the Np—O3 bond in (I). Water molecule makes two hydrogen bonds with O atoms of OH groups.

Experimental

The starting solution for the synthesis of (I) was slightly acidic (pH ~3) 0.15 M237NpO2(NO3)2. The preparation of such solutions is described by Charushnikova et al. (2007). For the synthesis of (I), 1 ml of 0.15 M NpO2(NO3)2 aqueous solution was taken into a bubble flask, 1 ml of 5 M LiOH solution was added, then ozonized oxygen (10% mass of O3) was passed through the solution over a period of 2 h. Aliquots of 0.1 ml of the solution were put into plastic containers, 0.05, 0.1 or 0.2 ml of 16.7 M NaOH was added, and the containers were placed into a desiccator with granulated KOH (to absorb CO2 and water vapour). After four days at room temperature almost all the NpVII was crystallized as bulk black crystals.

Refinement

The H atoms of the OH-group and crystallization water molecule were located on a difference Fourier map and refined with individual displacement parameters and O—H distances restrained to 0.82 (2) and 0.85 (2) Å, respectively.

Figures

Fig. 1.
A view of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are represented by circles of arbitrary size. Dashed line indicates the hydrogen-bonding interaction. [Symmetry code: (i) 1 - ...
Fig. 2.
The unit cell of (I).

Crystal data

Na3[NpO4(OH)2]·2H2OF000 = 392
Mr = 440.02Dx = 3.829 Mg m3
Monoclinic, P21/cMo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 5517 reflections
a = 7.8166 (3) Åθ = 3.9–40.0º
b = 7.7703 (2) ŵ = 13.79 mm1
c = 6.8211 (2) ÅT = 100 (2) K
β = 112.9139 (14)ºPlate, black
V = 381.60 (2) Å30.12 × 0.08 × 0.02 mm
Z = 2

Data collection

Bruker Kappa APEXII area-detector diffractometer2357 independent reflections
Radiation source: fine-focus sealed tube1920 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.024
T = 100(2) Kθmax = 40.0º
ω and [var phi] scansθmin = 3.9º
Absorption correction: multi-scan(SADABS; Sheldrick, 2004)h = −14→14
Tmin = 0.522, Tmax = 0.770k = −12→14
16264 measured reflectionsl = −12→12

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.010All H-atom parameters refined
wR(F2) = 0.021  w = 1/[σ2(Fo2) + (0.0059P)2 + 0.087P] where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
2357 reflectionsΔρmax = 0.75 e Å3
70 parametersΔρmin = −0.88 e Å3
3 restraintsExtinction correction: none
Primary atom site location: structure-invariant direct methods

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 (Å2)

xyzUiso*/Ueq
Np0.50000.50000.50000.00406 (1)
Na10.50000.50000.00000.00859 (9)
Na20.85815 (7)0.32123 (6)0.90540 (8)0.01157 (8)
O10.65824 (10)0.56060 (10)0.78208 (12)0.00757 (11)
O20.37890 (10)0.71543 (9)0.45784 (12)0.00792 (11)
O30.72436 (10)0.59020 (9)0.37305 (12)0.00862 (11)
H30.715 (3)0.693 (2)0.349 (4)0.031 (6)*
O40.97126 (12)0.44316 (15)0.24784 (14)0.01657 (15)
H4A0.892 (4)0.493 (2)0.286 (5)0.021 (6)*
H4B1.071 (2)0.428 (3)0.354 (3)0.029 (5)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Np0.00487 (2)0.00387 (2)0.00377 (2)0.00001 (2)0.00205 (1)−0.00008 (1)
Na10.0114 (2)0.0080 (2)0.0080 (2)0.0013 (2)0.0056 (2)0.0006 (2)
Na20.01207 (18)0.01314 (18)0.00847 (17)0.00321 (15)0.00287 (14)−0.00015 (15)
O10.0084 (3)0.0080 (3)0.0059 (3)−0.0006 (2)0.0023 (2)−0.0011 (2)
O20.0097 (3)0.0055 (2)0.0086 (3)0.0015 (2)0.0037 (2)0.0006 (2)
O30.0091 (3)0.0075 (3)0.0102 (3)0.0010 (2)0.0049 (2)0.0020 (2)
O40.0077 (3)0.0293 (4)0.0106 (3)0.0028 (3)0.0013 (3)−0.0068 (3)

Geometric parameters (Å, °)

Np—O11.8975 (7)Na2—O2i2.4655 (9)
Np—O2i1.8891 (7)Na2—O2vii2.5150 (9)
Np—O21.8891 (7)Na2—O4viii2.6263 (13)
Np—O1i1.8975 (7)Na2—O4ix2.7033 (12)
Np—O32.3451 (7)O1—Na1vi2.3223 (7)
Np—O3i2.3451 (7)O2—Na1x2.3783 (7)
Na1—O1ii2.3223 (7)O2—Na2i2.4655 (9)
Na1—O1i2.3223 (7)O2—Na2xi2.5150 (9)
Na1—O2iii2.3783 (7)O3—H30.815 (15)
Na1—O2iv2.3783 (7)O4—Na2ii2.3510 (10)
Na1—O32.5626 (8)O4—Na2xii2.6263 (13)
Na1—O3v2.5626 (8)O4—Na2ix2.7033 (12)
Na2—O4vi2.3510 (10)O4—H4A0.856 (17)
Na2—O12.3633 (9)O4—H4B0.840 (16)
O1—Np—O291.41 (3)O2iii—Na1—O387.25 (2)
O1—Np—O390.82 (3)O2iv—Na1—O392.75 (2)
O2—Np—O394.67 (3)O1ii—Na1—O3v75.46 (2)
O2i—Np—O2180.0O1i—Na1—O3v104.54 (2)
O2i—Np—O188.59 (3)O2iii—Na1—O3v92.75 (2)
O2i—Np—O1i91.41 (3)O2iv—Na1—O3v87.25 (2)
O2—Np—O1i88.59 (3)O3—Na1—O3v180.00 (3)
O1—Np—O1i180.0O4vi—Na2—O188.70 (4)
O2i—Np—O385.33 (3)O4vi—Na2—O2i152.85 (4)
O1i—Np—O389.18 (3)O1—Na2—O2i66.37 (3)
O2i—Np—O3i94.67 (3)O4vi—Na2—O2vii79.02 (3)
O2—Np—O3i85.33 (3)O1—Na2—O2vii84.77 (3)
O1—Np—O3i89.18 (3)O2i—Na2—O2vii87.77 (3)
O1i—Np—O3i90.82 (3)O4vi—Na2—O4viii131.72 (4)
O3—Np—O3i180.0O1—Na2—O4viii138.70 (3)
O1ii—Na1—O1i180.00 (2)O2i—Na2—O4viii74.89 (3)
O1ii—Na1—O2iii91.16 (3)O2vii—Na2—O4viii108.07 (3)
O1i—Na1—O2iii88.84 (3)O4vi—Na2—O4ix93.44 (4)
O1ii—Na1—O2iv88.84 (3)O1—Na2—O4ix71.74 (3)
O1i—Na1—O2iv91.16 (3)O2i—Na2—O4ix88.88 (3)
O2iii—Na1—O2iv180.0O2vii—Na2—O4ix155.55 (3)
O1ii—Na1—O3104.54 (2)O4viii—Na2—O4ix94.370 (16)
O1i—Na1—O375.46 (2)H4A—O4—H4B110 (3)

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

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O3—H3···O1iii0.815 (15)1.976 (16)2.7866 (10)173 (2)
O4—H4A···O30.856 (17)1.799 (17)2.6538 (12)178 (2)
O4—H4B···O3ix0.840 (16)1.931 (16)2.7612 (12)169 (2)

Symmetry codes: (iii) x, −y+3/2, z−1/2; (ix) −x+2, −y+1, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SG2217).

References

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