Acta Cryst. (2007). E63, i176 [ doi:10.1107/S1600536807039025 ]
The title compound, Na3[NpO4(OH)2], contains complex [NpO4(OH)2]3- anions, having a distorted tetragonal bipyramidal form. The Np atom occupies a special position on a twofold axis. The Np-O distances are 1.8981 (13) and 1.9012 (12) Å in the NpO4 group and 2.3145 (11) Å to the OH groups. The main distortion of the tetragonal bipyramid is a shift of the O atoms of the OH groups from ideal positions, the corresponding O-Np-O angle being 173.80 (7)°. The orientation of the OH groups differs significantly from the centrosymmetric arrangement found in other compounds with [NpO4(OH)2]3- anions.
The starting solution for the synthesis of (I) was slightly acidic (pH ~3) 0.15 M 237NpO2(NO3)2. The preparation of such solutions is described by Charushnikova et al. (2007). For the synthesis of (I), 0.2 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. An 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 were 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.
The H atom of the OH group was located on a difference Fourier-map and refined with O—H distance restrained to 0.82 (2) Å and individual isotropic displacement parameter.
Largest electron density peak on the final difference Fourier-synthesis is 1.071 e Å−3 (1.20 Å from O2), the deepest hole is −1.490 e Å−3 (1.67 Å from Na1).
Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT-Plus (Bruker, 1998); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.
![[Figure 1]](./sg2188fig1thm.gif)
| 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. [Symmetry code: (i) 1 − x, 1 − y, z.] |
![[Figure 2]](./sg2188fig2thm.gif)
| Fig. 2. The packing of (I) showing three-dimensional net of hydrogen bonds (dashed lines). |
| Na3[NpO4(OH)2] | F000 = 1408 |
| Mr = 403.99 | Dx = 4.399 Mg m−3 |
| Orthorhombic, Fdd2 | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: F 2 -2d | Cell parameters from 8824 reflections |
| a = 20.0791 (6) Å | θ = 4.1–45.0º |
| b = 5.9534 (2) Å | µ = 17.21 mm−1 |
| c = 10.2062 (3) Å | T = 100 (2) K |
| V = 1220.04 (7) Å3 | Plate, black |
| Z = 8 | 0.20 × 0.06 × 0.04 mm |
| Bruker Kappa APEXII area-detector diffractometer | 2442 independent reflections |
| Radiation source: fine-focus sealed tube | 2258 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.023 |
| T = 100(2) K | θmax = 45.0º |
| ω and φ scans | θmin = 4.1º |
| Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | h = −39→39 |
| Tmin = 0.378, Tmax = 0.546 | k = −11→11 |
| 21081 measured reflections | l = −20→19 |
| Refinement on F2 | Hydrogen site location: difference Fourier map |
| Least-squares matrix: full | All H-atom parameters refined |
| R[F2 > 2σ(F2)] = 0.012 | w = 1/[σ2(Fo2) + 2.58P] where P = (Fo2 + 2Fc2)/3 |
| wR(F2) = 0.022 | (Δ/σ)max = 0.001 |
| S = 1.25 | Δρmax = 1.07 e Å−3 |
| 2442 reflections | Δρmin = −1.49 e Å−3 |
| 52 parameters | Extinction correction: none |
| 2 restraints | Absolute structure: Flack (1983), with 1136 Friedel pairs |
| Primary atom site location: structure-invariant direct methods | Flack parameter: 0.039 (12) |
| Secondary atom site location: difference Fourier map |
| Na3[NpO4(OH)2] | V = 1220.04 (7) Å3 |
| Mr = 403.99 | Z = 8 |
| Orthorhombic, Fdd2 | Mo Kα |
| a = 20.0791 (6) Å | µ = 17.21 mm−1 |
| b = 5.9534 (2) Å | T = 100 (2) K |
| c = 10.2062 (3) Å | 0.20 × 0.06 × 0.04 mm |
| Bruker Kappa APEXII area-detector diffractometer | 2442 independent reflections |
| Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | 2258 reflections with I > 2σ(I) |
| Tmin = 0.378, Tmax = 0.546 | Rint = 0.023 |
| 21081 measured reflections |
| R[F2 > 2σ(F2)] = 0.012 | All H-atom parameters refined |
| wR(F2) = 0.022 | Δρmax = 1.07 e Å−3 |
| S = 1.25 | Δρmin = −1.49 e Å−3 |
| 2442 reflections | Absolute structure: Flack (1983), with 1136 Friedel pairs |
| 52 parameters | Flack parameter: 0.039 (12) |
| 2 restraints |
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 > 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. |
| x | y | z | Uiso*/Ueq | ||
| Np1 | 0.5000 | 0.5000 | 0.53211 (2) | 0.00494 (1) | |
| Na1 | 0.5000 | 0.5000 | 0.86871 (10) | 0.00964 (14) | |
| Na2 | 0.65942 (4) | 0.75441 (14) | 0.45853 (8) | 0.01332 (11) | |
| O1 | 0.55153 (7) | 0.6409 (2) | 0.66461 (14) | 0.01161 (19) | |
| O2 | 0.55254 (6) | 0.6438 (2) | 0.40181 (13) | 0.00956 (17) | |
| O3 | 0.42959 (5) | 0.80708 (19) | 0.51985 (14) | 0.00980 (16) | |
| H3 | 0.3955 (13) | 0.777 (6) | 0.483 (4) | 0.025 (9)* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Np1 | 0.00478 (2) | 0.00542 (2) | 0.00464 (2) | −0.00093 (4) | 0.000 | 0.000 |
| Na1 | 0.0127 (3) | 0.0077 (3) | 0.0085 (4) | 0.0009 (3) | 0.000 | 0.000 |
| Na2 | 0.0175 (3) | 0.0125 (3) | 0.0100 (3) | −0.0028 (3) | −0.0028 (2) | −0.0007 (2) |
| O1 | 0.0122 (4) | 0.0120 (5) | 0.0106 (5) | −0.0027 (4) | −0.0039 (4) | −0.0019 (4) |
| O2 | 0.0098 (4) | 0.0091 (4) | 0.0097 (4) | 0.0009 (3) | 0.0041 (3) | 0.0017 (3) |
| O3 | 0.0087 (3) | 0.0089 (3) | 0.0118 (5) | 0.0011 (3) | 0.0007 (3) | −0.0018 (3) |
| Np1—O1 | 1.8981 (13) | Na1—O1 | 2.4725 (17) |
| Np1—O1i | 1.8981 (13) | Na2—O3iv | 2.2653 (16) |
| Np1—O2i | 1.9012 (12) | Na2—O2v | 2.2723 (15) |
| Np1—O2 | 1.9012 (12) | Na2—O2 | 2.3183 (15) |
| Np1—O3i | 2.3145 (11) | Na2—O1vi | 2.3451 (16) |
| Np1—O3 | 2.3145 (11) | O1—Na2v | 2.3451 (16) |
| Na1—O3ii | 2.3870 (14) | O2—Na2vi | 2.2723 (15) |
| Na1—O3iii | 2.3870 (14) | O2—Na1vii | 2.3924 (13) |
| Na1—O2ii | 2.3924 (13) | O3—Na2viii | 2.2653 (16) |
| Na1—O2iii | 2.3924 (13) | O3—Na1vii | 2.3870 (14) |
| Na1—O1i | 2.4725 (17) | O3—H3 | 0.800 (18) |
| O1—Np1—O1i | 89.13 (9) | O2ii—Na1—O2iii | 163.77 (8) |
| O1—Np1—O2i | 178.96 (7) | O3ii—Na1—O1i | 162.86 (5) |
| O1i—Np1—O2i | 89.82 (5) | O3iii—Na1—O1i | 97.66 (4) |
| O1—Np1—O2 | 89.82 (5) | O2ii—Na1—O1i | 103.60 (5) |
| O1i—Np1—O2 | 178.96 (7) | O2iii—Na1—O1i | 90.16 (5) |
| O2—Np1—O2i | 91.22 (8) | O3ii—Na1—O1 | 97.66 (4) |
| O1—Np1—O3i | 93.13 (5) | O3iii—Na1—O1 | 162.86 (5) |
| O1i—Np1—O3i | 91.29 (5) | O2ii—Na1—O1 | 90.16 (5) |
| O2i—Np1—O3i | 86.87 (5) | O2iii—Na1—O1 | 103.60 (5) |
| O2—Np1—O3i | 88.79 (5) | O1i—Na1—O1 | 65.19 (6) |
| O1—Np1—O3 | 91.29 (5) | O2ii—Na1—Na2ii | 38.73 (3) |
| O1i—Np1—O3 | 93.13 (5) | O2iii—Na1—Na2ii | 135.15 (4) |
| O2i—Np1—O3 | 88.79 (5) | O3iv—Na2—O2v | 119.80 (6) |
| O2—Np1—O3 | 86.87 (5) | O3iv—Na2—O2 | 95.39 (5) |
| O3i—Np1—O3 | 173.80 (7) | O2v—Na2—O2 | 129.18 (6) |
| O3ii—Na1—O3iii | 99.48 (7) | O3iv—Na2—O1vi | 103.59 (6) |
| O3ii—Na1—O2ii | 75.13 (4) | O2v—Na2—O1vi | 112.99 (6) |
| O3iii—Na1—O2ii | 94.25 (5) | O2—Na2—O1vi | 89.98 (5) |
| O3ii—Na1—O2iii | 94.25 (5) | Np1—O3—H3 | 112 (3) |
| O3iii—Na1—O2iii | 75.13 (4) |
| Symmetry codes: (i) −x+1, −y+1, z; (ii) −x+1, −y+3/2, z+1/2; (iii) x, y−1/2, z+1/2; (iv) x+1/4, −y+7/4, z−1/4; (v) −x+5/4, y+1/4, z+1/4; (vi) −x+5/4, y−1/4, z−1/4; (vii) x, y+1/2, z−1/2; (viii) x−1/4, −y+7/4, z+1/4. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O3—H3···O1ix | 0.800 (18) | 2.25 (2) | 3.0255 (17) | 164 (4) |
| Symmetry codes: (ix) x−1/4, −y+5/4, z−1/4. |
| Np1—O1 | 1.8981 (13) | Np1—O3 | 2.3145 (11) |
| Np1—O2 | 1.9012 (12) | ||
| O1—Np1—O1i | 89.13 (9) | O1—Np1—O3i | 93.13 (5) |
| O1—Np1—O2i | 178.96 (7) | O1—Np1—O3 | 91.29 (5) |
| O1—Np1—O2 | 89.82 (5) | O2—Np1—O3 | 86.87 (5) |
| O2—Np1—O2i | 91.22 (8) | O3i—Np1—O3 | 173.80 (7) |
| Symmetry codes: (i) −x+1, −y+1, z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O3—H3···O1ii | 0.800 (18) | 2.25 (2) | 3.0255 (17) | 164 (4) |
| Symmetry codes: (ii) x−1/4, −y+5/4, z−1/4. |
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The title compound, (I) (Fig. 1), contains complex anions [NpO4(OH)2]3−, having a form of distorted tetragonal bipyramid. The main bond lengths and angles in this anion are given in Table 1. The Np atom occupies a special position on a twofold axis. The main distortion of the tetragonal bipyramid is a shift of O atoms of the OH groups from ideal positions, the corresponding O—Np—O angle being 173.80 (7)°. The orientaion of the OH groups differs significantly from centrosymmetric (Fig. 1) whereas in all other compounds with [NpO4(OH)2]3− anions (Tomilin et al., 1981b,c, 1983; Grigor'ev et al., 1986, 1993; Charushnikova et al., 2007) these anions occupy centrosymmetric positions. Basing on diffractometrically studied structures of NpVII compounds with alkaline cations, one can notice that the Np—O distances to the OH groups become longer in the sequence Na–K–Cs. The corresponding distances are 2.370 (5) Å for K3[NpO4(OH)2]·2H2O (Charushnikova et al., 2007) and 2.41 (1) Å for Cs3[NpO4(OH)2]·3H2O (Grigor'ev et al., 1993). The Np—O distances in the NpO4 groups remain practically the same.
The Na1 atom occupies a special position on twofold axis and has a distorted octahedral oxygen environment. The Na2 atom is in general position with distorted tetrahedral oxygen environment.
The OH group acts as proton donor in a weak hydrogen bond with an O atom of NpO4 group of a neighbouring anion (Table 2). The resulting hydrogen bond net in (I) is three-dimensional (Fig. 2).