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The crystal structure of oxonium neodymium bis­(sulfate), (H3O)Nd(SO4)2, shows a two-dimensional layered framework assembled from SO4 tetra­hedra and NdO9 tricapped trigonal prisms. One independent sulfate group makes four S-O-Nd linkages, while the other makes five such connections to generate an unprecedented anhydrous anionic [Nd(SO4)2]- layer. To achieve charge balance, H3O+ cations are inserted between adjacent layers where they participate in hydrogen-bonding inter­actions with the sulfate O atoms of adjacent layers.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270109054316/sq3229sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270109054316/sq3229Isup2.hkl
Contains datablock I

Comment top

Over the past few decades, great efforts have been made to synthesize new topological solid inorganic materials because of their functional applications in ion-exchange, adsorption, catalysis and radioactive waste remediation. Recently, studies of lanthanide sulfates have yielded important advancements in this field. Compared with Zn, Al and Ge, the lanthanides can have flexible bond lengths and high coordination numbers, which offer the possibility to form solid state materials with novel topological structures (Dan et al., 2004; Doran et al., 2002; Xu et al., 2007; Zhou, Chen, Jiang et al., 2009; Zhou, Chen, Zhu et al., 2009; Zhu et al., 2009). Two-dimensional lanthanide sulfates that have been reported previously include Eu2(SO4)3(H2O)8 and some protonated organic amine-templated sulfates (Xu et al., 2007; Zhou, Chen, Jiang et al., 2009; Zhu et al., 2009). To date, no oxonium cation-templated lanthanide sulfate has been reported. In this work, we designed and synthesized the title compound, which represents the first example with H3O+ cations inserted into a layered neodymium sulfate.

The asymmetric unit of (H3O)Nd(SO4)2 contains ten crystallographically independent non-H atoms including one Nd3+ cation, two sulfate anions and one oxonium cation (Fig. 1). The Nd3+ cation is coordinated by nine O atoms from seven sulfate groups with typical tricapped trigonal–prismatic coordination geometry. Atoms O3, O3ii, O6, O6i, O7iv and O4iii form the trigonal prism, while O2, O7 and O8v are the face-capping atoms (symmetry codes as in figure caption). The sulfate group centered by S1 makes four S—O—Nd linkages using one O2, two O3 and one O4 atoms, while the S2 sulfate group makes five S—O—Nd connections via two O6, two O7 and one O8 atoms. Thus, each sulfate group has one terminal O atom that is not coordinated to the metal center. The SO4 tetrahedra connect the NdO9 polyhedra to generate an unprecedented anhydrous anionic Nd–O–S layer of composition [Nd(SO4)2]- in the bc plane (Fig. 2). All the previously reported Ln–O–S layers include coordinated water molecules, because of the high affinity of Ln3+ cations for water. To the best of our knowledge, this is the first example of an Ln–O–S layer without coordinated water molecules. In the reported layered europium sulfate Eu2(SO4)3(H2O)8 (Xu et al., 2007), for example, the Eu3+ cation coordinates to eight O atoms including four terminal water molecules; this behaviour is in contrast to that of (H3O)Nd(SO4)2, in which each Nd3+ cation forms nine coordination bonds with SO42- groups without coordinated water molecules, leading to high stability of the Nd–O–S layers. The thickness of each Nd—O—S layer is about 6.48 (2) Å, which is thicker than the reported Eu–O–S layer [5.62 (3) Å] in Eu2(SO4)3(H2O)8. The H3O+ cations are inserted between adjacent Nd–O–S layers, resulting in the novel (H3O)nn+ sheet shown in Fig. 3. The distances between adjacent H3O+ cations are 4.20 (2)–4.26 (2) Å, indicating no direct hydrogen-bonding interactions between the cations. The H3O+ cations form hydrogen bonds with O atoms of sulfate groups (Fig. 4 and Table 2), the shortest interactions being to the terminal O1 and O5 atoms that are not part of the Nd coordination environment.

Thermal analysis of (H3O)Nd(SO4)2 in N2 atmosphere shows a broad weight loss of 5.20% within the temperature range 323–752 K, which is attributed to the removal of water (the calculated value is 5.07%), while a subsequent weight loss of 49.78% between 753 and 1373 K may correspond to the loss of SO3.

Related literature top

For related literature, see: Dan et al. (2004); Doran et al.(2002); Xu et al. (2007); Zhou, Chen, Jiang et al. (2009); Zhou, Chen, Zhu et al.(2009); Zhu et al.(2009).

Experimental top

The title crystal was synthesized by hydrothermal reaction using Nd(NO3).6H2O (0.3441 g), H2SO4, diethylenetriamine (0.2215 g) and H2O (1.1 ml). The mixture was put into a 25 ml Teflon-lined autoclave and heated at 453 K for 7 d. After the sample was cooled to room temperature, washed with distilled water, filtered and dried in air, block-shaped pink crystals were obtained.

Refinement top

The oxonium H atoms were located from a difference map and included in the refinement with the O—H bond lengths restrained to 0.87 (2) Å and the H···H distances restrained to 1.50 (2) Å. The H atoms were assigned fixed isotropic displacement parameters equal to 1.2Ueq(O9).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the complete coordination environment around atom Nd1. Displacement ellipsoids are shown at the 50% probability level. [Symmetry codes: (i) x, -y + 1/2, z + 1/2 ; (ii) x, -y + 1/2, z - 1/2; (iii) -x, -y, -z + 2; (iv) -x, y + 1/2, -z + 3/2; (v) -x, y - 1/2, -z + 3/2.]
[Figure 2] Fig. 2. The structure of a single Nd–O–S layer as seen perpendicular to the layer (along the a axis).
[Figure 3] Fig. 3. The arrangement of oxonium O atoms in the (H3O)nn+ cation layer. The view is along the a axis.
[Figure 4] Fig. 4. A view along the c axis showing the stacking of Nd–O–S layers with H3O+ cations in between. O—H···O hydrogen bonds are shown as broken lines.
oxonium neodymium bis(sulfate) top
Crystal data top
(H3O)Nd(SO4)2F(000) = 668
Mr = 355.38Dx = 3.440 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 1682 reflections
a = 8.8593 (8) Åθ = 2.5–25.5°
b = 7.1787 (6) ŵ = 8.19 mm1
c = 10.7955 (10) ÅT = 293 K
β = 91.671 (1)°Block, pink
V = 686.28 (11) Å30.10 × 0.08 × 0.06 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer
1278 independent reflections
Radiation source: fine-focus sealed tube1208 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.027
ω scansθmax = 25.5°, θmin = 2.3°
Absorption correction: multi-scans
(SADABS; Sheldrick, 2003)
h = 109
Tmin = 0.495, Tmax = 0.639k = 88
3416 measured reflectionsl = 1013
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.021H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.056 w = 1/[σ2(Fo2) + (0.0291P)2 + 1.5142P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max = 0.006
1278 reflectionsΔρmax = 0.99 e Å3
120 parametersΔρmin = 0.83 e Å3
6 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0276 (3)
Crystal data top
(H3O)Nd(SO4)2V = 686.28 (11) Å3
Mr = 355.38Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.8593 (8) ŵ = 8.19 mm1
b = 7.1787 (6) ÅT = 293 K
c = 10.7955 (10) Å0.10 × 0.08 × 0.06 mm
β = 91.671 (1)°
Data collection top
Bruker APEXII CCD
diffractometer
1278 independent reflections
Absorption correction: multi-scans
(SADABS; Sheldrick, 2003)
1208 reflections with I > 2σ(I)
Tmin = 0.495, Tmax = 0.639Rint = 0.027
3416 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0216 restraints
wR(F2) = 0.056H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.99 e Å3
1278 reflectionsΔρmin = 0.83 e Å3
120 parameters
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Nd10.053643 (14)0.171284 (17)0.849456 (11)0.00778 (4)
S10.26635 (7)0.16280 (8)1.08715 (6)0.00887 (14)
S20.17688 (7)0.16786 (8)0.61239 (6)0.00820 (14)
O10.3900 (2)0.0450 (3)1.12558 (18)0.0188 (5)
O20.2909 (2)0.2584 (3)0.96801 (17)0.0143 (4)
O30.12590 (19)0.0511 (2)1.05951 (16)0.0118 (4)
O40.2333 (2)0.3023 (2)1.18370 (18)0.0155 (5)
O50.3385 (2)0.1499 (2)0.61071 (19)0.0156 (5)
O60.1282 (2)0.3352 (2)0.68792 (17)0.0116 (4)
O70.0996 (2)0.0118 (2)0.68149 (16)0.0121 (4)
O80.1174 (2)0.1746 (2)0.48741 (18)0.0132 (5)
O90.4351 (2)0.3516 (3)1.1568 (2)0.0324 (7)
H10.3569 (8)0.4255 (14)1.153 (3)0.039*
H20.4210 (19)0.2313 (9)1.152 (3)0.039*
H30.5235 (8)0.395 (2)1.138 (2)0.039*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Nd10.00890 (7)0.00816 (7)0.00634 (7)0.00058 (4)0.00117 (6)0.00010 (5)
S10.0088 (3)0.0112 (3)0.0067 (3)0.0013 (2)0.0018 (2)0.0003 (2)
S20.0095 (3)0.0084 (3)0.0068 (3)0.0000 (2)0.0015 (2)0.0001 (2)
O10.0146 (9)0.0205 (9)0.0209 (10)0.0032 (8)0.0037 (8)0.0019 (8)
O20.0146 (8)0.0187 (9)0.0098 (8)0.0049 (8)0.0019 (7)0.0021 (8)
O30.0122 (8)0.0147 (8)0.0085 (8)0.0040 (7)0.0009 (7)0.0016 (7)
O40.0183 (9)0.0150 (9)0.0137 (9)0.0020 (7)0.0071 (8)0.0052 (7)
O50.0121 (9)0.0163 (9)0.0182 (10)0.0016 (7)0.0002 (8)0.0029 (8)
O60.0148 (9)0.0102 (9)0.0099 (9)0.0014 (7)0.0009 (7)0.0028 (7)
O70.0141 (8)0.0114 (8)0.0109 (8)0.0021 (7)0.0001 (7)0.0014 (7)
O80.0172 (9)0.0136 (9)0.0090 (9)0.0038 (7)0.0050 (8)0.0004 (7)
O90.0247 (12)0.0348 (13)0.0378 (16)0.0024 (9)0.0023 (12)0.0004 (10)
Geometric parameters (Å, º) top
Nd1—O8i2.4230 (19)S1—O31.5028 (18)
Nd1—O4ii2.437 (2)S2—O51.437 (2)
Nd1—O3iii2.4770 (17)S2—O81.463 (2)
Nd1—O32.4923 (17)S2—O71.5004 (18)
Nd1—O7iv2.5020 (17)S2—O61.5079 (17)
Nd1—O22.5077 (18)O3—Nd1iii2.4770 (17)
Nd1—O72.5095 (17)O4—Nd1i2.437 (2)
Nd1—O6v2.5368 (16)O6—Nd1iv2.5368 (16)
Nd1—O62.6187 (18)O7—Nd1v2.5020 (17)
Nd1—S13.1396 (7)O8—Nd1ii2.4230 (19)
Nd1—S23.2275 (7)O9—H10.872 (7)
S1—O11.4356 (19)O9—H20.874 (6)
S1—O21.4793 (19)O9—H30.874 (8)
S1—O41.4808 (19)
O8i—Nd1—O4ii148.15 (6)O8i—Nd1—S295.64 (5)
O8i—Nd1—O3iii68.29 (6)O4ii—Nd1—S280.21 (5)
O4ii—Nd1—O3iii141.47 (6)O3iii—Nd1—S284.89 (4)
O8i—Nd1—O375.38 (6)O3—Nd1—S2149.16 (4)
O4ii—Nd1—O3122.63 (6)O7iv—Nd1—S290.18 (4)
O3iii—Nd1—O364.33 (7)O2—Nd1—S2155.25 (4)
O8i—Nd1—O7iv75.10 (6)O7—Nd1—S226.77 (4)
O4ii—Nd1—O7iv73.36 (6)O6v—Nd1—S291.62 (4)
O3iii—Nd1—O7iv142.32 (6)O6—Nd1—S227.45 (4)
O3—Nd1—O7iv114.91 (6)S1—Nd1—S2177.175 (16)
O8i—Nd1—O295.87 (6)O1—S1—O2113.21 (11)
O4ii—Nd1—O278.45 (6)O1—S1—O4111.09 (12)
O3iii—Nd1—O2119.77 (6)O2—S1—O4109.60 (11)
O3—Nd1—O255.44 (6)O1—S1—O3111.33 (11)
O7iv—Nd1—O271.79 (6)O2—S1—O3102.50 (10)
O8i—Nd1—O7108.53 (6)O4—S1—O3108.72 (11)
O4ii—Nd1—O781.72 (6)O1—S1—Nd1133.04 (8)
O3iii—Nd1—O769.67 (6)O2—S1—Nd151.70 (7)
O3—Nd1—O7128.22 (6)O4—S1—Nd1115.84 (8)
O7iv—Nd1—O7115.84 (4)O3—S1—Nd151.27 (7)
O2—Nd1—O7155.51 (6)O5—S2—O8112.13 (12)
O8i—Nd1—O6v134.63 (6)O5—S2—O7112.31 (11)
O4ii—Nd1—O6v77.20 (6)O8—S2—O7108.15 (10)
O3iii—Nd1—O6v67.88 (6)O5—S2—O6110.32 (11)
O3—Nd1—O6v75.78 (6)O8—S2—O6111.55 (10)
O7iv—Nd1—O6v149.74 (6)O7—S2—O6101.94 (10)
O2—Nd1—O6v95.74 (6)O5—S2—Nd1128.16 (9)
O7—Nd1—O6v65.73 (6)O8—S2—Nd1119.62 (8)
O8i—Nd1—O679.65 (6)O7—S2—Nd148.87 (7)
O4ii—Nd1—O683.01 (6)O6—S2—Nd153.18 (7)
O3iii—Nd1—O699.45 (6)S1—O2—Nd1100.72 (9)
O3—Nd1—O6153.92 (6)S1—O3—Nd1iii143.38 (10)
O7iv—Nd1—O664.62 (5)S1—O3—Nd1100.67 (8)
O2—Nd1—O6135.89 (6)Nd1iii—O3—Nd1115.67 (7)
O7—Nd1—O654.17 (5)S1—O4—Nd1i135.76 (11)
O6v—Nd1—O6118.65 (4)S2—O6—Nd1iv138.02 (11)
O8i—Nd1—S182.98 (5)S2—O6—Nd199.37 (8)
O4ii—Nd1—S1102.27 (5)Nd1iv—O6—Nd1112.04 (7)
O3iii—Nd1—S192.31 (4)S2—O7—Nd1v137.46 (10)
O3—Nd1—S128.06 (4)S2—O7—Nd1104.36 (9)
O7iv—Nd1—S191.84 (4)Nd1v—O7—Nd1117.11 (7)
O2—Nd1—S127.58 (4)S2—O8—Nd1ii146.11 (11)
O7—Nd1—S1151.74 (4)H1—O9—H2119.1 (13)
O6v—Nd1—S187.63 (4)H1—O9—H3119.0 (13)
O6—Nd1—S1153.63 (4)H2—O9—H3117.9 (15)
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x, y+1/2, z1/2; (iii) x, y, z+2; (iv) x, y+1/2, z+3/2; (v) x, y1/2, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O9—H1···O4vi0.87 (1)2.27 (1)3.080 (3)155 (2)
O9—H2···O10.87 (1)2.02 (1)2.893 (3)175 (3)
O9—H3···O5vii0.87 (1)2.23 (1)2.986 (3)146 (1)
Symmetry codes: (vi) x, y1, z; (vii) x+1, y1/2, z+1/2.

Experimental details

Crystal data
Chemical formula(H3O)Nd(SO4)2
Mr355.38
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)8.8593 (8), 7.1787 (6), 10.7955 (10)
β (°) 91.671 (1)
V3)686.28 (11)
Z4
Radiation typeMo Kα
µ (mm1)8.19
Crystal size (mm)0.10 × 0.08 × 0.06
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scans
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.495, 0.639
No. of measured, independent and
observed [I > 2σ(I)] reflections
3416, 1278, 1208
Rint0.027
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.021, 0.056, 1.03
No. of reflections1278
No. of parameters120
No. of restraints6
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.99, 0.83

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected bond lengths (Å) top
Nd1—O8i2.4230 (19)Nd1—O22.5077 (18)
Nd1—O4ii2.437 (2)Nd1—O72.5095 (17)
Nd1—O3iii2.4770 (17)Nd1—O6v2.5368 (16)
Nd1—O32.4923 (17)Nd1—O62.6187 (18)
Nd1—O7iv2.5020 (17)
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x, y+1/2, z1/2; (iii) x, y, z+2; (iv) x, y+1/2, z+3/2; (v) x, y1/2, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O9—H1···O4vi0.873 (9)2.269 (11)3.080 (3)154.5 (15)
O9—H2···O10.874 (7)2.021 (8)2.893 (3)175 (3)
O9—H3···O5vii0.872 (10)2.225 (13)2.986 (3)145.6 (12)
Symmetry codes: (vi) x, y1, z; (vii) x+1, y1/2, z+1/2.
 

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