inorganic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

Reinvestigation of tris­­odium di­hydroxido­tetra­oxidoneptunate(VII) dihydrate

aA. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky prospekt, 119991 Moscow, Russian Federation
*Correspondence e-mail: grigoriev@ipc.rssi.ru

(Received 11 December 2007; accepted 14 December 2007; online 21 December 2007)

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[Tomilin, S. V., Volkov, Yu. F., Kapshukov, I. I. & Rykov, A. G. (1981a). Radiokhimiya, 23, 710-715.]). 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[Tomilin, S. V., Volkov, Yu. F., Kapshukov, I. I. & Rykov, A. G. (1981b). Radiokhimiya, 23, 704-709.]), Na3[NpO4(OH)2]·4H2O (Tomilin et al., 1981c[Tomilin, S. V., Volkov, Yu. F., Kapshukov, I. I. & Rykov, A. G. (1981c). Radiokhimiya, 23, 862-867.]), K3[NpO4(OH)2]·2H2O (Tomilin et al., 1983[Tomilin, S. V., Volkov, Yu. F., Visyashcheva, G. I. & Kapshukov, I. I. (1983). Radiokhimiya, 25, 58-62.]). Diffractometric structure determinations have been made for [Co(NH3)6][NpO4(OH)2]·2H2O (Grigor'ev et al., 1986[Grigor'ev, M. S., Gulev, B. F. & Krot, N. N. (1986). Radiokhimiya, 28, 690-694.]), Cs3[NpO4(OH)2]·3H2O (Grigor'ev et al., 1993[Grigor'ev, M. S., Baturin, N. A., Tananaev, I. G. & Krot, N. N. (1993). Radiokhimiya, 35, 12-16.]), K3[NpO4(OH)2]·2H2O (Charushnikova et al., 2007[Charushnikova, I. A., Krot, N. N., Starikova, Z. A. & Poliakova, I. N. (2007). Radiokhimiya, 49, 12-16.]) and Na3[NpO4(OH)2] (Grigoriev & Krot, 2007[Grigoriev, M. S. & Krot, N. N. (2007). Acta Cryst. E63, i176.]).[link]

[Scheme 1]

Experimental

Crystal data
  • Na3[NpO4(OH)2]·2H2O

  • Mr = 440.02

  • Monoclinic, P 21 /c

  • 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[Sheldrick, G. M. (2004). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.522, Tmax = 0.770

  • 16264 measured reflections

  • 2357 independent reflections

  • 1920 reflections with I > 2σ(I)

  • Rint = 0.024

Refinement
  • R[F2 > 2σ(F2)] = 0.010

  • wR(F2) = 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

Table 1
Selected geometric parameters (Å, °)

Np—O1 1.8975 (7)
Np—O2 1.8891 (7)
Np—O3 2.3451 (7)
O1—Np—O2 91.41 (3)
O1—Np—O3 90.82 (3)
O2—Np—O3 94.67 (3)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O3—H3⋯O1i 0.815 (15) 1.976 (16) 2.7866 (10) 173 (2)
O4—H4A⋯O3 0.856 (17) 1.799 (17) 2.6538 (12) 178 (2)
O4—H4B⋯O3ii 0.840 (16) 1.931 (16) 2.7612 (12) 169 (2)
Symmetry codes: (i) [x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]; (ii) -x+2, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2006[Bruker (2006). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 1998[Bruker (1998). SMART (Version 5.059) and SAINT-Plus (Version 6.01). Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a[Sheldrick, G. M. (1997a). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a[Sheldrick, G. M. (1997a). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: SHELXTL97 (Sheldrick, 1997b[Sheldrick, G. M. (1997b). SHELXTL. Version 5.10. Bruker AXS Inc., Madison, Wisconsin, USA.]); software used to prepare material for publication: SHELXTL97.

Supporting information


Comment top

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.

Related literature top

The structure of Na3[NpO4(OH)2].2H2O was investigated by photographic technique with visual estimation of reflection intensities by Tomilin et al. (1981a). 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), Na3[NpO4(OH)2].4H2O (Tomilin et al., 1981c), K3[NpO4(OH)2].2H2O (Tomilin et al., 1983). Diffractometric structure determinations have been made for [Co(NH3)6][NpO4(OH)2].2H2O (Grigor'ev et al., 1986), Cs3[NpO4(OH)2].3H2O (Grigor'ev et al., 1993), K3[NpO4(OH)2].2H2O (Charushnikova et al., 2007) and Na3[NpO4(OH)2] (Grigoriev & Krot, 2007).

Experimental top

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), 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 top

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.

Structure description top

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.

The structure of Na3[NpO4(OH)2].2H2O was investigated by photographic technique with visual estimation of reflection intensities by Tomilin et al. (1981a). 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), Na3[NpO4(OH)2].4H2O (Tomilin et al., 1981c), K3[NpO4(OH)2].2H2O (Tomilin et al., 1983). Diffractometric structure determinations have been made for [Co(NH3)6][NpO4(OH)2].2H2O (Grigor'ev et al., 1986), Cs3[NpO4(OH)2].3H2O (Grigor'ev et al., 1993), K3[NpO4(OH)2].2H2O (Charushnikova et al., 2007) and Na3[NpO4(OH)2] (Grigoriev & Krot, 2007).

Computing details top

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

Figures top
[Figure 1] 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 - x, 1 - y, 1 - z.]
[Figure 2] Fig. 2. The unit cell of (I).
trisodium dihydroxidotetraoxidoneptunate(VII) dihydrate top
Crystal data top
Na3[NpO4(OH)2]·2H2OF(000) = 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 = 3.9–40.0°
b = 7.7703 (2) ŵ = 13.79 mm1
c = 6.8211 (2) ÅT = 100 K
β = 112.9139 (14)°Plate, black
V = 381.60 (2) Å30.12 × 0.08 × 0.02 mm
Z = 2
Data collection top
Bruker Kappa APEXII area-detector
diffractometer
2357 independent reflections
Radiation source: fine-focus sealed tube1920 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
ω and φ scansθmax = 40.0°, θmin = 3.9°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)
h = 1414
Tmin = 0.522, Tmax = 0.770k = 1214
16264 measured reflectionsl = 1212
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)] = 0.010Hydrogen site location: difference Fourier map
wR(F2) = 0.021All H-atom parameters refined
S = 1.04 w = 1/[σ2(Fo2) + (0.0059P)2 + 0.087P]
where P = (Fo2 + 2Fc2)/3
2357 reflections(Δ/σ)max = 0.001
70 parametersΔρmax = 0.75 e Å3
3 restraintsΔρmin = 0.88 e Å3
Crystal data top
Na3[NpO4(OH)2]·2H2OV = 381.60 (2) Å3
Mr = 440.02Z = 2
Monoclinic, P21/cMo Kα radiation
a = 7.8166 (3) ŵ = 13.79 mm1
b = 7.7703 (2) ÅT = 100 K
c = 6.8211 (2) Å0.12 × 0.08 × 0.02 mm
β = 112.9139 (14)°
Data collection top
Bruker Kappa APEXII area-detector
diffractometer
2357 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)
1920 reflections with I > 2σ(I)
Tmin = 0.522, Tmax = 0.770Rint = 0.024
16264 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0103 restraints
wR(F2) = 0.021All H-atom parameters refined
S = 1.04Δρmax = 0.75 e Å3
2357 reflectionsΔρmin = 0.88 e Å3
70 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
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) top
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, º) top
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, z1; (iii) x, y+3/2, z1/2; (iv) x+1, y1/2, z+1/2; (v) x+1, y+1, z; (vi) x, y, z+1; (vii) x+1, y1/2, 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, z1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O1iii0.82 (2)1.98 (2)2.7866 (10)173 (2)
O4—H4A···O30.86 (2)1.80 (2)2.6538 (12)178 (2)
O4—H4B···O3ix0.84 (2)1.93 (2)2.7612 (12)169 (2)
Symmetry codes: (iii) x, y+3/2, z1/2; (ix) x+2, y+1, z+1.

Experimental details

Crystal data
Chemical formulaNa3[NpO4(OH)2]·2H2O
Mr440.02
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)7.8166 (3), 7.7703 (2), 6.8211 (2)
β (°) 112.9139 (14)
V3)381.60 (2)
Z2
Radiation typeMo Kα
µ (mm1)13.79
Crystal size (mm)0.12 × 0.08 × 0.02
Data collection
DiffractometerBruker Kappa APEXII area-detector
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2004)
Tmin, Tmax0.522, 0.770
No. of measured, independent and
observed [I > 2σ(I)] reflections
16264, 2357, 1920
Rint0.024
(sin θ/λ)max1)0.904
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.010, 0.021, 1.04
No. of reflections2357
No. of parameters70
No. of restraints3
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.75, 0.88

Computer programs: APEX2 (Bruker, 2006), SAINT-Plus (Bruker, 1998), SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), SHELXTL97 (Sheldrick, 1997b).

Selected geometric parameters (Å, º) top
Np—O11.8975 (7)Np—O32.3451 (7)
Np—O21.8891 (7)
O1—Np—O291.41 (3)O2—Np—O394.67 (3)
O1—Np—O390.82 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O1i0.815 (15)1.976 (16)2.7866 (10)173 (2)
O4—H4A···O30.856 (17)1.799 (17)2.6538 (12)178 (2)
O4—H4B···O3ii0.840 (16)1.931 (16)2.7612 (12)169 (2)
Symmetry codes: (i) x, y+3/2, z1/2; (ii) x+2, y+1, z+1.
 

References

First citationBruker (1998). SMART (Version 5.059) and SAINT-Plus (Version 6.01). Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruker (2006). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCharushnikova, I. A., Krot, N. N., Starikova, Z. A. & Poliakova, I. N. (2007). Radiokhimiya, 49, 12–16.  Google Scholar
First citationGrigor'ev, M. S., Baturin, N. A., Tananaev, I. G. & Krot, N. N. (1993). Radiokhimiya, 35, 12–16.  CAS Google Scholar
First citationGrigor'ev, M. S., Gulev, B. F. & Krot, N. N. (1986). Radiokhimiya, 28, 690–694.  CAS Google Scholar
First citationGrigoriev, M. S. & Krot, N. N. (2007). Acta Cryst. E63, i176.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (1997a). SHELXS97 and SHELXL97. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (1997b). SHELXTL. Version 5.10. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationSheldrick, G. M. (2004). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationTomilin, S. V., Volkov, Yu. F., Kapshukov, I. I. & Rykov, A. G. (1981a). Radiokhimiya, 23, 710–715.  CAS Google Scholar
First citationTomilin, S. V., Volkov, Yu. F., Kapshukov, I. I. & Rykov, A. G. (1981b). Radiokhimiya, 23, 704–709.  CAS Google Scholar
First citationTomilin, S. V., Volkov, Yu. F., Kapshukov, I. I. & Rykov, A. G. (1981c). Radiokhimiya, 23, 862–867.  CAS Google Scholar
First citationTomilin, S. V., Volkov, Yu. F., Visyashcheva, G. I. & Kapshukov, I. I. (1983). Radiokhimiya, 25, 58–62.  CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds