ISSN 1063-7745, Crystallography Reports, 009, Vol. 54, No. 5, pp. 85 857. Pleiades Publishing, Inc., 009. Original Russian Text L.B. Serezhkina, A.V. Vologzhanina, A.V. Marukhnov, D.V. Pushkin, V.N. Serezhkin, 009, published in Kristallografiya, 009, Vol. 54, No. 5, pp. 898 903. STRUCTURE OF ORGANIC COMPOUNDS Dedicated to the memory of G.B. Bokiі on the occasion of his 100th birthday Synthesis and Crystal Structure of Na 3 (H 3 O)[UO (SeO 3 ) ] H O L. B. Serezhkina a, *, A. V. Vologzhanina b, A. V. Marukhnov a, D. V. Pushkin a, and V. N. Serezhkin a a Samara State University, ul. Akademika Pavlova 1, Samara, 443011 Russia * e-mail: Lserezh@ssu.samara.ru b Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova 8, Moscow, 119991 Russia Received January 9, 009 Abstract Single crystals of the compound Na 3 (H 3 O)[UO (SeO 3 ) ] H O (I) have been synthesized, and their structure has been investigated using X-ray diffraction. Compound I crystallizes in the triclinic system with the unit cell parameters a = 9.543(6) Å, b = 9.60(7) Å, c = 11.74(8) Å, α = 66.693(16), β = 84.10(), γ = 63.686(14), space group P1, Z =, and R = 0.0734. The uranium-containing structural units of the crystals are [UO (SeO 3 ) ] chains, which belong to the crystal-chemical group AB B 11 + (A =, B UO = SeO 3, B 11 = ) of the uranyl complexes. The structures of the compounds containing the [UO (SeO 3 ) ] anionic complexes are compared. PACS numbers: 61.66.-f DOI: 10.1134/S1063774509050186 SeO 3 INTRODUCTION Among the uranyl selenite compounds studied to date, the largest group involves compounds containing [UO (SeO 3 ) ] anionic complexes. This paper describes the synthesis and reports on the results of the X-ray structural investigation of the compound Na 3 (H 3 O)[UO (SeO 3 ) ] H O (I), which is the first sodium-containing representative of the diselenitouranylate group. SAMPLE PREPARATION AND EXPERIMENTAL TECHNIQUE Crystals of compound I were prepared using the hydrothermal synthesis. The UO 3 H O, Na SeO 3, and H SeO 3 compounds and cyanoguanidine taken in a molar ratio of 1 : 3 : 3 : 3 were placed in an autoclave. Water in an amount corresponding to a concentration of 4 wt % U was added to the autoclave. The reaction mixture was kept in the autoclave at a temperature of 110 С for 100 h. According to the data obtained from the X-ray diffraction analysis, the precipitated yellow crystals had the composition Na 3 (H 3 O)[UO (SeO 3 ) ] H O. Cyanoguanidine under the above conditions did not enter into the composition of the complex formed. The structure of compound I was determined using single-crystal X-ray diffraction analysis. An experimental set of reflections was collected on a Bruker APEX II diffractometer (MoKa radiation, graphite monochromator) [1]. It was revealed that the crystal of compound I is a systematic twin. By using the Cell_Now program included in the Bruker APEX software package [1], it was established that the twinning of this crystal is associated with the presence of two components rotated by 179.8 with respect to each other. The structure was solved by direct methods. All the non-hydrogen atoms were located from the difference electron-density syntheses and refined in the anisotropic approximation with the use of the HKLF 5 instruction and the additional scale parameter (the BASF instruction). The positions of the hydrogen atoms were calculated geometrically and refined in the isotropic approximation within the rigid-body model with U iso (H) = 1.5U eq (O i ), where U eq (O) are the equivalent thermal parameters of the oxygen atoms to which the corresponding hydrogen atoms are bonded. All calculations were performed with the SHELXTL (Version 5.10) program package []. The crystallographic data, experimental details, parameters of the structure solution and refinement, and the final reliability factors for compound I are summarized in Table 1. The selected geometric parameters are listed in Table. The coordinates and thermal parameters of the basis atoms in the structure of compound I have 85
SYNTHESIS AND CRYSTAL STRUCTURE 853 been deposited with the Inorganic Crystal Structure Database (ICSD no. 4048). RESULTS AND DISCUSSION In the structure of compound I, the coordination polyhedra of the two crystallographically independent uranium atoms are UO 7 pentagonal bipyramids in which the oxygen atoms of the uranyl ions are located on the principal axis and the equatorial plane is occupied by five oxygen atoms of four selenite groups. The volumes of the Voronoi Dirichlet polyhedra in the form of pentagonal prisms for the uranium atoms are equal to 9.1 and 9. Å 3, respectively, which is in agreement with the average value of 9.(3) Å 3 for uranium(vi) atoms in the environment of oxygen atoms [3]. The uranium atoms are insignificantly displaced from the equatorial plane formed by five oxygen atoms (by 0.0(1) and 0.03(1) Å for the uranium(1) and uranium() atoms, respectively). Four crystallographically independent selenium atoms form SeO 3 trigo- nal pyramids. Half of the selenite groups (involving the Se(1) and Se(4) atoms) play the role of bidentate bridging ligands of the B type, and the other selenite groups (containing the Se() and Se(3) atoms) are bidentate bridging cyclic ligands of the B 11 type (the notation of the types of ligand coordination is given according to [4]). The volumes of the Voronoi Dirichlet polyhedra of the Se(1) Se(4) atoms are equal to 1.6, 16.0, 16.3, and 13.1 Å 3, which agree (within σ) with the average value of 13.5(1.7) Å 3 for selenium(iv) atoms in selenite ions [5]. The magnitude of the vector D A, which characterizes the displacement of the atoms from the center of gravity of their Voronoi Dirichlet polyhedra [6], differs considerably from zero, which indicates that the Se(IV) atoms have a stereochemically active lone electron pair. In particular, these vectors have the magnitudes D A = 0.5 and 0.54 Å for the selenium atoms in selenite ions with the B type of coordination and 0.71 and 0.75 Å for the selenium atoms in selenite ions with the B 11 type of coordination, which coincides (within the twice the error) with the average magnitude D A for Se(IV) atoms in selenite ions (0.58(11) Å) [5]. The coordination of the sodium atoms was determined using the method of intersecting spheres [7]. According to the data obtained, the sodium atoms in the structure of compound I form the Na(1)О 6, Na()О 7, and Na(3)О 6 coordination polyhedra (Table 3). The Na O bonds (.3.93 Å) in Table 3 correspond to intersections of the I 3 and I types. The Na(1)О 6 polyhedra contain one oxygen atom of the uranyl group, three oxygen atoms of the bidentate bridging selenite ions, and two oxygen atoms of the SeO 3 bidentate bridging cyclic ions. In similar Na(3)О 6 polyhedra, there is one oxygen atom of the Table 1. Crystallographic data, experimental details, and parameters of the structure solution and refinement for the Na 3 (H 3 O)[UO (SeO 3 ) ] H O compound Chemical formula Na 3 (H 3 O)[UO (SeO 3 ) ] H O Crystal system, space group, Z Triclinic, P 1, a, Å 9.543(6) b, Å 9.60(7) c, Å 11.74(8) α, deg 66.693(16) β, deg 84.10() γ, deg 63.686(14) V, Å 3 88.4(10) D x, g/cm 3 4.343 Radiation, λ, Å МоК α, 0.71073 µ, mm 1 6.740 Temperature T, K 100() Sample size, mm 0.18 0.06 0.0 Scan mode ω Absorption correction, T min, Semiempirical, from equivalent reflections, 0.153, 0.588 T max θ max, deg 8 Range of indices h, k, l 1 h 1, 11 k 1, 0 l 15 Number of reflections measured/number of unique re- 4846/4846, 3440 flections (N 1 ), R int /number of reflections with I > σ(i) (N ) Refinement technique Least-squares method on F Number of parameters refined Weighting scheme 03 1/[σ ( ) + (0.140P) ], P = ( + )/3 Discrepancy factors: wr for N 1 0.14 R 1 for N 0.0734 S 1.00 Residual (maximum and 4.657/ 4.117 minimum) electron densities ρ max / ρ min, e Å 3 Program packages used APEX [1], SHELXTL version 5.10 [] F o F o F c
854 SEREZHKINA et al. Table. Selected geometric parameters of the structure of the Na 3 (H 3 O)[UO (SeO 3 ) ] H O compound Bond* d, Å Ω, %** Angle* ω, deg Pentagonal bipyramids UO 7 U(1) O(1) 1.88(18) 0.8 O1U1O 178.9(7) U(1) O() 1.77(19) 1.0 O5U1O6 76.9(6) U(1) O(5).46() 10. O6U1O7 83.8(6) U(1) O(6).90(19) 13.3 O7U1O8 75.8(6) U(1) O(7).64(18) 13.3 O8U1O9 63.3(6) U(1) O(8).31() 11.7 O9U1O5 60.4(6) U(1) O(9).46(17) 9.6 U() O(3) 1.803(19) 1. O3UO4 178.9(8) U() O(4) 1.777(19) 1. O8UO9 61.3(6) U() (O8).490(19) 9.1 O9UO10 78.6(6) U() O(9).39() 11.1 O10UO11 8.1(7) U() O(10).85(17) 13. O11UO1 76.4(7) U() O(11).95(17) 13. O1UO8 6.(6) U() O(1).437(18) 10.8 SeO 3 ions Se(1) O(13) 1.64() 4.7 O13Se1O11a 104.0(9) Se(1)1 O(11a) 1.674(18) 4.0 O13Se1O7 103.8(9) Se(1) O(7) 1.718(18) 3.6 O11aSe1O7 10.5(9) Se() O(14) 1.63() 6.0 O14SeO1 108.6(10) Se() O(1) 1.730(18) 3.3 O14SeO8 103.(10) Se() O(8) 1.746(18) 3. O1SeO8 94.(9) Se(3) O(15) 1.64() 5.1 O15Se3O5 10.(11) Se(3) O(5) 1.680(19) 3.5 O15Se3O9 104.0(11) Se(3) O(9) 1.743(19) 3.3 O5Se3O9 91.8(9) Se(4) O(16) 1.659(17) 4.9 O16Se4O10 103.0(10) Se(4) O(10) 1.694(18) 3.9 O16Se4O6b 105.5(9) Se(4) O(6b) 1.701(17) 3.4 O10Se4O6b 99.0(9) * The coordinates of the atoms are obtained from the basis set through the symmetry transformations: (a) x, y + 1, z and (b) x, y 1, z. ** Ω is the solid angle (expressed in percent of the total solid angle of 4π steradians) at which the face shared by the Voronoi Dirichlet polyhedra of the neighboring atoms is seen from the nucleus of any of them. water molecule instead of one oxygen atom of the selenite ion (B type). The environment of the Na() atom involves three uranyl oxygen atoms, two oxygen atoms of the SeO 3 bidentate bridging cyclic ions, one oxygen atom of the bidentate bridging selenite ion, and one oxygen atom of the water molecule. The volumes of the Voronoi Dirichlet polyhedra of the sodium atoms are equal to 14.9, 15., and 14.5 Å 3, which is in agreement with the average value of 15.1() Å 3 for sodium atoms in the oxygen environ- ment [8]. It should be noted that the bounding of the sodium ions to the oxygen atoms is responsible for the considerable difference in the arms of the almost + linear groups UO. The elongated U=O bonds (1.88, 1.803 Å) in the uranyl ions correspond to the O(1) and O(3) atoms, which are coordinated to three and two different sodium atoms, respectively, whereas the shorter U=O bonds (1.77, 1.777 Å) are formed by the O() and O(4) atoms, which are not involved in the coordination of the sodium atoms.
SYNTHESIS AND CRYSTAL STRUCTURE 855 Table 3. Analysis of the environment of the sodium atoms in the structure of the Na 3 (H 3 O)[UO (SeO 3 ) ] H O compound according to the method of intersecting spheres [7] Central atom Atom X of the environment* Interatomic distance r(na X), Å Solid angle Ω(Na X), % Volume of the intersection of two spheres (Å 3 ) with radii** r S r S r S R SD R SD r S R SD R SD Intersection type Na(1), coordination O(3).385 17.43 0.0003.451 0 1.30 I 3 O(15).399 16.55 0.0566 0 0.9736 I number is 6 O(13).414 16.75 0 1.8754 0 0.8569 I O(14).43 16.58 0.309 0 1.161 I O(16).44 16.19 0 1.9139 0 0.8757 I O(16).58 14.1 0 1.3858 0 0.5355 I Na() 3.386 0.14 0.173 0 0 0 I 1 #Se(4) 3.388 1.19 0 0 0 0 #I 0 #O(10) 3.731 0.41 0 0 0 0 #I 0 #O(1) 3.976 0.31 0 0 0 0 #I 0 #H( 4.038 0.10 0 0 0 0 #I 0 #H() 4.181 0.17 0 0 0 0 #I 0 Na(), coordination O(16).350 17.3 0.0034.3008 0 1.1815 I 3 O(17).379 14.33 0.0006 0.7469 0 0.314 I number is 7 3 O(15).411 15.79 0.0066 0 0.9771 I O(1).563 13.88 0 1.5981 0 0.6943 I O(3).597 14.01 0 1.567 0 0.6707 I #H(1).689 3.70 0 0.4611 0 0.0764 #I O(1).838 11.7 0 0.715 0 0.179 I #H().855 1.17 0 0.484 0 0.0766 #I O(9).98 6.90 0 0.439 0 0.0560 I Na(1) 3.386 0.14 0.173 0 0 0 I 1 #O(6) 3.611 0.30 0 0 0 0 #I 0 O(8) 3.774 1.03 0 0 0 0 I 0 #O(16) 4.096 0.14 0 0 0 0 #I 0 Na(3), coordination O(17).34 16.8 0.0080 0.8813 0 0.704 I 3 O(13).367 16.3 0.0015.0659 0 0.9441 I number is 6 3 O(13).391 16.18 0.0001 1.9678 0 0.8788 I 3 O(14).40 15.94 0.3195 0 1.0916 I O(1).54 14.14 0 1.6788 0 0.6786 I O(15).633 13.07 0 1.1861 0 0.3897 I #H().743.48 0 0.7478 0 0.1649 #I #H(1).851 0.66 0 0.19 0 0 #I 1 #Se(1) 3.359 0.47 0 0 0 0 #I 0 O(8) 3.360 3.06 0 0 0 0 I 0 #Se(1) 3.369 0.03 0 0 0 0 #I 0 O(7) 3.501 1.38 0 0 0 0 I 0 #O(14) 4.050 0.01 0 0 0 0 #I 0 * The atoms marked with the symbol # correspond to the so-called nonessential neighbors for which the midpoint of the Na X segment does not lie on the surface of the Voronoi Dirichlet polyhedron of the sodium ion. ** In all products (r S is the Slater radius, and R SD is the radius of the sphere with the volume equal to the volume of the Voronoi Dirichlet polyhedron of the Na or X atom), the first and second factors are the corresponding radii of the Na and X atoms, respectively.
856 SEREZHKINA et al. (a) Se(4) O(15) Se(3) O(5) O(10) O() O(6) O(16) O(9) U(1) O(3) O(4) O(1) U() O(8) O(7) O(11) Se() (O(13)Se(1) O(1) O(14) (b) (a) (b) U Se O 0 a c b Fig.. Structures of the [UO (SeO 3 ) ] chains in (a) complexes I, II, and III with the crystal chemical formula AB B 11 and (b) complexes IV and V with the crystal chemical formula AТ 1 М 1. Fig. 1. Crystal structure of the Na 3 (H 3 O)[UO (SeO 3 ) ] H O compound: (a) structure of the [UO (SeO 3 ) ] chains (the thermal ellipsoids of atoms are drawn at the 50% probability level, and only the symmetrically independent atoms are labeled) and (b) bonding of the {Na 3 [(UO )(SeO 3 ) ] (H O)} layers by H 3 O + ions (the view in the direction of the а crystallographic axis). In the crystals of compound I, the main structural units are [UO (SeO 3 ) ] chains, which belong to the crystal chemical group AB B 11 + (A = UO ) of the uranyl complexes and are extended along the [010] direction. In these chains (Fig. 1a), the uranyl ions joined in pairs by two bidentate bridging selenite groups (B type) sequentially alternate with those linked by two bidentate bridging cyclic selenite groups (B 11 type). The [UO (SeO 3 ) ] chains are joined by the Na + ions and the water molecules bonded to them into {Na 3 [(UO )(SeO 3 ) ] (H O)} layers with hydroxonium ions in between (Fig. 1b). The neighboring layers {Na 3 [(UO )(SeO 3 ) ] (H O)} are linked through the electrostatic interactions of hydroxonium ions and a system of hydrogen bonds, which are formed with the participation of the hydrogen atoms of the H 3 O + ions or water molecules and the oxygen atoms of the selenite ions (Table 4). The structures of eight selenitouranylates containing [UO (SeO 3 ) ] complexes have been investigated Table 4. Geometric parameters of the hydrogen bonds in the structure of the Na 3 (H 3 O)[UO (SeO 3 ) ] H O compound* O H O** Distances, Å O O O H H O O H O angle, deg Ω (O H), % Ω (H O), % O(17) H(1) O(5c).7(3) 0.85.00 143 3.3 19.5 O(17) H() O(1d).86(3) 0.85. 13 3.5 17.0 O(18) H(3) O(5).85(3) 0.85.01 170 8.0 0.1 O(18) H(4) O(1e).84(3) 0.85.01 167 30.6 0.4 O(18) H(5) O(6f).89(3) 0.85.38 179 30.3 13.6 * The contacts with the distances H O <.5 Å, the O H O angles > 110, and the angles Ω(H O) > 13% are taken into account. ** The coordinates of the atoms are obtained from the basis set through the symmetry transformations: (c) x + 1, y +, z + 1; (d) x +, y + 1, z + 1; (e) x 1, y + 1, z; (f) x + 1, y +, z +.
SYNTHESIS AND CRYSTAL STRUCTURE 857 to date (their crystal chemical analysis was performed in [9]). In four out of the eight compounds, these complexes have a chain structure. In the structures of the compounds (NH 4 )(CN 3 H 6 )[UO (SeO 3 ) ] (II) [9] and Sr[UO (SeO 3 ) ] H O (III) [10], the chains are formed by bidentate bridging (B type) and bidentate bridging cyclic (B 11 type) selenite groups (AB B 11 complexes, Fig. a). In turn, in the structures of the compounds Sr[UO (SeO 3 ) ] (IV) [11] and Ca[UO (SeO 3 ) ] (V) [10], one selenite ion fulfills the function of a monodentate terminal ligand (M 1 type) and the other selenite ion plays the role of a tridentate bridging cyclic ligand (T 1 type) (AТ 1 М 1 complexes, Fig. b). Earlier [9], it was assumed that the choice of the coordination mode in the [UO (SeO 3 ) ] chains (bidentate in compounds II and III or tridentate and monodentate in compounds IV and V) is affected by the presence of hydrogen-containing cations and/or water molecules capable of forming hydrogen bonds with the oxygen atoms of the selenite ions in the composition of the compound. The results obtained in our work confirm the proposed hypothesis, because the Na 3 (H 3 O)[UO (SeO 3 ) ] H O crystals containing the H 3 O + cations and the water molecules under investigation, like crystals II and III, belong to the crystal chemical group AB B 11 of the uranyl complexes. ACKNOWLEDGMENTS This study was supported by the Council on Grants from the President of the Russian Federation (grant no. MK-966.008.3). REFERENCES 1. Bruker APEX: Software Package (Bruker AXS, Madison, WI, United States, 005).. G. M. Sheldrick, SHELXTL: Structure Determination Software Suite, Version 5.10 (Bruker AXS, Madison, WI, United States, 1998). 3. V. N. Serezhkin, V. A. Blatov, and A. P. Shevchenko, Koord. Khim. 1 (3), 480 (1995). 4. V. N. Serezhkin, T. N. Polynova, and M. A. Poraі- Koshits, Koord. Khim. 1 (4), 53 (1995). 5. O. V. Shishkina, L. B. Serezhkina, V. N. Serezhkin, and Yu. A. Buslaev, Zh. Neorg. Khim. 44 (1), 016 (1999) [Russ. J. Inorg. Chem. 44 (1), 191 (1999)]. 6. V. N. Serezhkin and Yu. A. Buslaev, Zh. Neorg. Khim. 4 (7), 1178 (1997) [Russ. J. Inorg. Chem. 4 (7), 1064 (1997)]. 7. V. N. Serezhkin, Yu. N. Mikhailov, and Yu. A. Buslaev, Zh. Neorg. Khim. 4 (1), 036 (1997) [Russ. J. Inorg. Chem. 4 (1), 1871 (1997)]. 8. V. N. Serezhkin, G. V. Kryuchkova, and V. S. Kazakevich, Zh. Neorg. Khim. 48 (8), 13 (003) [Russ. J. Inorg. Chem. 48 (8), 1199 (003)]. 9. A. V. Marukhnov, E. V. Peresypkina, A. V. Virovets, D. V. Pushkin, and L. B. Serezhkina, Koord. Khim. 35 (1), 4 (009) [Russ. J. Coord. Chem. 35 (1), 4 (000)]. 10. P. M. Almond, S. M. Peper, E. Bakker, and T. E. Albrecht-Schmitt, J. Solid State Chem. 168 (), 358 (00). 11. P. M. Almond and T. E. Albrecht-Schmitt, Am. Mineral. 89 (7), 976 (004). Translated by O. Borovik-Romanova