Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103028312/bc1032sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103028312/bc1032Isup2.hkl |
Transparent yellow crystals of Rb6Na2[(UO2)(CO3)3]2(H2O), up to 1 mm in maximum dimension, were synthesized from a solution containing Na2CO3 (0.026 g), RbNO3 (0.111 g) and UO2(NO3)2(H2O)6 (0.123 g) in ultra-pure water (25 ml). Following evaporation in an open beaker for 28 d at 293 K under ambient pressure, crystals were recovered from the beaker walls.
The positions of the U, Rb, Na, C and most O atoms were determined by direct methods. The remaining O atoms were located by subsequent difference Fourier syntheses. The locations of the highest peak and deepest hole in the difference Fourier map are 0.75 Å from U and 0.51 Å from Rb, respectively. H-atom positions were not determined in the refinement. However, atom O2 is a possible hydrogen-bond acceptor, as it is the nearest O atom to O5 [O2···O5 3.122 (9) Å].
Data collection: SMART-NT (Bruker, 2001); cell refinement: SAINT-NT (Bruker, 2000); data reduction: SAINT-NT; program(s) used to solve structure: SHELXTL-NT (Bruker, 1998); program(s) used to refine structure: SHELXTL-NT; molecular graphics: ATOMS (Dowty, 2000); software used to prepare material for publication: SHELXTL-NT and WinGX (Farrugia, 1999).
Rb6Na2[(UO2)(CO3)3]2(H2O) | Dx = 3.808 Mg m−3 |
Mr = 1476.94 | Mo Kα radiation, λ = 0.71073 Å |
Hexagonal, P62c | Cell parameters from 1623 reflections |
Hall symbol: P -6c -2c | θ = 3.3–33.8° |
a = 9.4316 (7) Å | µ = 23.95 mm−1 |
c = 8.3595 (8) Å | T = 297 K |
V = 643.99 (9) Å3 | Anhedral, yellow |
Z = 1 | 0.15 × 0.12 × 0.12 mm |
F(000) = 660 |
Bruker APEX CCD area-detector diffractometer | 787 reflections with I > 2σ(I) |
ϕ and ω scans | Rint = 0.073 |
Absorption correction: empirical (using intensity measurements) via ψ-scan (SHELXTL-NT; Bruker, 1998) | θmax = 34.6°, θmin = 2.5° |
Tmin = 0.044, Tmax = 0.056 | h = −14→14 |
12787 measured reflections | k = −14→14 |
958 independent reflections | l = −13→13 |
Refinement on F2 | w = 1/[σ2(Fo2) + (0.052P)2] where P = (Fo2 + 2Fc2)/3 |
Least-squares matrix: full | (Δ/σ)max < 0.001 |
R[F2 > 2σ(F2)] = 0.034 | Δρmax = 2.04 e Å−3 |
wR(F2) = 0.085 | Δρmin = −1.69 e Å−3 |
S = 0.97 | Extinction correction: SHELXTL-NT (Bruker, 1998), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
958 reflections | Extinction coefficient: 0.044 (8) |
40 parameters | Absolute structure: Flack (1983), with 407 Friedel pairs |
0 restraints | Absolute structure parameter: −0.02 (4) |
Rb6Na2[(UO2)(CO3)3]2(H2O) | Z = 1 |
Mr = 1476.94 | Mo Kα radiation |
Hexagonal, P62c | µ = 23.95 mm−1 |
a = 9.4316 (7) Å | T = 297 K |
c = 8.3595 (8) Å | 0.15 × 0.12 × 0.12 mm |
V = 643.99 (9) Å3 |
Bruker APEX CCD area-detector diffractometer | 958 independent reflections |
Absorption correction: empirical (using intensity measurements) via ψ-scan (SHELXTL-NT; Bruker, 1998) | 787 reflections with I > 2σ(I) |
Tmin = 0.044, Tmax = 0.056 | Rint = 0.073 |
12787 measured reflections |
R[F2 > 2σ(F2)] = 0.034 | 0 restraints |
wR(F2) = 0.085 | Δρmax = 2.04 e Å−3 |
S = 0.97 | Δρmin = −1.69 e Å−3 |
958 reflections | Absolute structure: Flack (1983), with 407 Friedel pairs |
40 parameters | Absolute structure parameter: −0.02 (4) |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
U | 0.6667 | 0.3333 | 0.75 | 0.02461 (13) | |
Rb | 0.2764 (2) | 0.0 | 0.0 | 0.0602 (4) | |
Na | 0.3333 | 0.6667 | 0.75 | 0.0369 (12) | |
C | 0.9878 (15) | 0.6164 (13) | 0.75 | 0.0330 (19) | |
O1 | 0.9642 (8) | 0.4689 (15) | 0.75 | 0.046 (2) | |
O2 | 0.8564 (9) | 0.6250 (10) | 0.75 | 0.042 (2) | |
O3 | 0.6667 | 0.3333 | 0.9628 (10) | 0.0434 (17) | |
O4 | 1.1262 (10) | 0.7388 (11) | 0.75 | 0.043 (2) | |
O5 | 0.0 | 0.0 | 0.198 (4) | 0.078 (14) | 0.25 |
U11 | U22 | U33 | U12 | U13 | U23 | |
U | 0.02406 (16) | 0.02406 (16) | 0.0257 (2) | 0.01203 (8) | 0.0 | 0.0 |
Rb | 0.0726 (7) | 0.0552 (8) | 0.0471 (7) | 0.0276 (4) | 0.0049 (3) | 0.0099 (6) |
Na | 0.0437 (19) | 0.0437 (19) | 0.023 (2) | 0.0219 (10) | 0.0 | 0.0 |
C | 0.035 (5) | 0.025 (4) | 0.042 (5) | 0.017 (4) | 0.0 | 0.0 |
O1 | 0.026 (3) | 0.037 (5) | 0.069 (4) | 0.011 (4) | 0.0 | 0.0 |
O2 | 0.029 (4) | 0.028 (4) | 0.062 (5) | 0.010 (3) | 0.0 | 0.0 |
O3 | 0.049 (3) | 0.049 (3) | 0.032 (3) | 0.0247 (14) | 0.0 | 0.0 |
O4 | 0.029 (4) | 0.039 (4) | 0.059 (6) | 0.014 (4) | 0.0 | 0.0 |
O5 | 0.10 (2) | 0.10 (2) | 0.026 (14) | 0.052 (11) | 0.0 | 0.0 |
U—O3i | 1.779 (8) | Na—O4vii | 2.368 (9) |
U—O2ii | 2.418 (8) | Na—O3viii | 2.401 (8) |
U—O1 | 2.433 (6) | Na—O1ix | 3.018 (6) |
Rb—O2iii | 2.822 (6) | C—O4 | 1.237 (14) |
Rb—O1iv | 2.897 (9) | C—O2 | 1.281 (14) |
Rb—O4v | 2.992 (7) | C—O1 | 1.295 (17) |
Rb—O5vi | 3.086 (19) | ||
O2ii—U—O2 | 120.0140 | O4v—Rb—O3xiv | 122.42 (18) |
O2ii—U—O2x | 120.0080 | O4xiii—Rb—O3xiv | 62.6 (2) |
O2—U—O2x | 119.9780 | O5vi—Rb—O3xiv | 117.8 (3) |
O2ii—U—O1 | 66.9 (4) | O5—Rb—O3xiv | 124.3 (2) |
O2—U—O1 | 53.1 (4) | O3iv—Rb—O3xiv | 104.83 (5) |
O2x—U—O1 | 173.0 (4) | O2iii—Rb—O5viii | 118.3 (3) |
O2ii—U—O1ii | 53.1 (4) | O2xi—Rb—O5viii | 56.2 (3) |
O2—U—O1ii | 173.1 (4) | O1iv—Rb—O5viii | 173.7 (2) |
O2x—U—O1ii | 66.9 (4) | O1xii—Rb—O5viii | 89.4 (5) |
O2ii—U—O1x | 173.1 (4) | O4v—Rb—O5viii | 58.0 (3) |
O2—U—O1x | 66.9 (4) | O4xiii—Rb—O5viii | 116.2 (3) |
O2x—U—O1x | 53.1 (4) | O5vi—Rb—O5viii | 11.8 (10) |
O1—U—O1x | 119.990 (5) | O5—Rb—O5viii | 76.49 (16) |
O1ii—U—O1x | 119.988 (5) | O3iv—Rb—O5viii | 120.03 (19) |
O2iii—Rb—O2xi | 173.5 (3) | O3xiv—Rb—O5viii | 112.0 (2) |
O2iii—Rb—O1iv | 55.8 (2) | O2iii—Rb—O5xv | 56.2 (3) |
O2xi—Rb—O1iv | 129.9 (2) | O2xi—Rb—O5xv | 118.3 (3) |
O2iii—Rb—O1xii | 129.9 (2) | O1iv—Rb—O5xv | 89.4 (5) |
O2xi—Rb—O1xii | 55.8 (2) | O1xii—Rb—O5xv | 173.7 (2) |
O1iv—Rb—O1xii | 93.5 (4) | O4v—Rb—O5xv | 116.2 (3) |
O2iii—Rb—O4v | 92.07 (17) | O4xiii—Rb—O5xv | 58.0 (3) |
O2xi—Rb—O4v | 87.52 (17) | O5vi—Rb—O5xv | 76.49 (16) |
O1iv—Rb—O4v | 118.3 (2) | O5—Rb—O5xv | 11.8 (10) |
O1xii—Rb—O4v | 67.1 (2) | O3iv—Rb—O5xv | 112.0 (2) |
O4v—Rb—O4xiii | 172.9 (3) | O3xiv—Rb—O5xv | 120.04 (19) |
O2iii—Rb—O5vi | 110.4 (4) | O5viii—Rb—O5xv | 88.2 (8) |
O2xi—Rb—O5vi | 63.6 (4) | O4vii—Na—O4x | 120 |
O1iv—Rb—O5vi | 164.8 (6) | Naviii—O3—90 | 1_455 |
O1xii—Rb—O5vi | 101.1 (6) | Naxvi—O3—180 | 10_554 |
O4v—Rb—O5vi | 64.8 (4) | Naix—O1—73.2 (3) | 1_455 |
O4xiii—Rb—O5vi | 108.8 (4) | Naix—O1—46.8 (3) | 3_675 |
O2xi—Rb—O5 | 110.4 (4) | Naix—O1—166.7 (3) | 2_655 |
O5vi—Rb—O5 | 64.7 (11) | Naix—O1—90 | 10_554 |
O2iii—Rb—O3iv | 56.01 (19) | O4vii—Na—O1vii | 46.8 (3) |
O2xi—Rb—O3iv | 128.96 (19) | O4x—Na—O1vii | 73.2 (3) |
O1iv—Rb—O3iv | 55.78 (17) | O3viii—Na—O1vii | 90 |
O1xii—Rb—O3iv | 74.14 (19) | O3xvi—Na—O1vii | 90 |
O4v—Rb—O3iv | 62.6 (2) | O1ix—Na—O1vii | 120 |
O4xiii—Rb—O3iv | 122.42 (18) | O4x—Na—O1x | 46.8 (3) |
O5vi—Rb—O3iv | 124.3 (2) | O3viii—Na—O1x | 90 |
O5—Rb—O3iv | 117.8 (3) | O3xvi—Na—O1x | 90 |
O2iii—Rb—O3xiv | 128.95 (19) | O1ix—Na—O1x | 120 |
O2xi—Rb—O3xiv | 56.01 (19) | O4—C—O2 | 122.9 (10) |
O1iv—Rb—O3xiv | 74.13 (19) | O4—C—O1 | 122.5 (11) |
O1xii—Rb—O3xiv | 55.77 (17) | O2—C—O1 | 114.6 (10) |
Symmetry codes: (i) x, y, −z+3/2; (ii) −x+y+1, −x+1, z; (iii) −x+1, −x+y, −z+1; (iv) y, x−1, −z+1; (v) x−1, y−1, z−1; (vi) y, x, −z; (vii) x−1, y, z; (viii) y, x, z−1/2; (ix) −x+y+1, −x+2, z; (x) −y+1, x−y, z; (xi) −y+1, x−y, z−1; (xii) −x+y+1, −x+1, z−1; (xiii) x−y, −y+1, −z+1; (xiv) x, y, z−1; (xv) x, y, −z+1/2; (xvi) y, x, −z+2. |
Experimental details
Crystal data | |
Chemical formula | Rb6Na2[(UO2)(CO3)3]2(H2O) |
Mr | 1476.94 |
Crystal system, space group | Hexagonal, P62c |
Temperature (K) | 297 |
a, c (Å) | 9.4316 (7), 8.3595 (8) |
V (Å3) | 643.99 (9) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 23.95 |
Crystal size (mm) | 0.15 × 0.12 × 0.12 |
Data collection | |
Diffractometer | Bruker APEX CCD area-detector diffractometer |
Absorption correction | Empirical (using intensity measurements) via ψ-scan (SHELXTL-NT; Bruker, 1998) |
Tmin, Tmax | 0.044, 0.056 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 12787, 958, 787 |
Rint | 0.073 |
(sin θ/λ)max (Å−1) | 0.798 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.085, 0.97 |
No. of reflections | 958 |
No. of parameters | 40 |
Δρmax, Δρmin (e Å−3) | 2.04, −1.69 |
Absolute structure | Flack (1983), with 407 Friedel pairs |
Absolute structure parameter | −0.02 (4) |
Computer programs: SMART-NT (Bruker, 2001), SAINT-NT (Bruker, 2000), SAINT-NT, SHELXTL-NT (Bruker, 1998), ATOMS (Dowty, 2000), SHELXTL-NT and WinGX (Farrugia, 1999).
U—O3i | 1.779 (8) | Na—O4vii | 2.368 (9) |
U—O2ii | 2.418 (8) | Na—O3viii | 2.401 (8) |
U—O1 | 2.433 (6) | Na—O1ix | 3.018 (6) |
Rb—O2iii | 2.822 (6) | C—O4 | 1.237 (14) |
Rb—O1iv | 2.897 (9) | C—O2 | 1.281 (14) |
Rb—O4v | 2.992 (7) | C—O1 | 1.295 (17) |
Rb—O5vi | 3.086 (19) |
Symmetry codes: (i) x, y, −z+3/2; (ii) −x+y+1, −x+1, z; (iii) −x+1, −x+y, −z+1; (iv) y, x−1, −z+1; (v) x−1, y−1, z−1; (vi) y, x, −z; (vii) x−1, y, z; (viii) y, x, z−1/2; (ix) −x+y+1, −x+2, z. |
The compound Rb6Na2[(UO2)(CO3)3]2(H2O) was obtained by evaporation of a solution containing UO2(NO3)2(H2O)6, RbNO3 and Na2CO3 at ambient temperature and pressure. Rb6Na2[(UO2)(CO3)3]2(H2O) is structurally analogous to the mineral grimselite, K3Na[(UO2)(CO3)3](H2O) (Li & Burns, 2001). Each contains the uranyl tricarbonate cluster, [(UO2)(CO3)3], and crystallizes in space group P62c. However, these two compounds differ in their hydration state.
There is one symmetrically distinct UVI atom in the structure of Rb6Na2[(UO2)(CO3)3]2(H2O). This atom is part of a linear uranyl ion, (UO2)2+, which is coordinated by six equatorial O atoms, forming a uranyl hexagonal bipyramid. Three non-adjacent equatorial edges of the uranyl hexagonal bipyramid share edges with CO3 groups, giving the uranyl tricarbonate cluster, [(UO2)(CO3)3] (Fig 1). These clusters share edges with NaO8 hexagonal bipyramids, to form heteropolyhedral sheets parallel to (001) (Fig. 2). These sheets are stacked along [001], with voids in the resulting framework containing Rb cations and H2O molecules. The H2O sites are 25% occupied in the structure of Rb6Na2[(UO2)(CO3)3]2(H2O), whereas they are 50% occupied in the structure of grimselite. This difference in H2O content may be attributable to the larger size of the Rb+ cation.
Bond-valence sums were calculated for each ion using the parameters of Brese & O'Keeffe (1991), giving the following values: 6.18 for U, 4.15 for C, 1.29 for Rb and 1.15 for Na (Burns et al., 1997). The bond-valence sum for Rb is based on its coordination environment when the O5 site is occupied and the partial occupancy of this site may, therefore, represent a way to limit the overbonding of the Rb site. For atoms O1, O2, O3 and O4, the bond-valence sums are within the normal range (1.88–2.25). The bond-valence sum for atom O5 (0.32) is consistent with an H2O molecule.