Synthesis and X-ray diffraction study of (Cs0.5Ba0.25)[UO2(CH3COO)3] and Ba0.5[UO2(CH3COO)3]

Uranyl triacetate complexes (Cs_0.5Ba_0.25)[UO₂(CH₃COO)₃] (I) and Ba_0.5[UO₂(CH₃COO)₃] (II) are synthesized for the first time and their structures are determined by X-ray diffraction. Both compounds crystallize in the cubic crystal system. The crystal data are as follows: a = 17.3289(7) ?, V = 5203.7(4) ?³, space group I2₁3 and Z = 16 (I); a = 17.0515(8)?, V = 4957.8(4) ?³, space group I $ \bar 4 $ \bar 4 3d, and Z = 16 (II). In I and II, as in all uranyl triacetates studied earlier, the coordination polyhedron of the uranium atom is a hexagonal bipyramid whose vertices are occupied by the oxygen atoms of the uranyl and three acetate groups. The uranium-containing group belongs to the AB ₃⁰¹ (A = UO₂²⁺, B ⁰¹ = CH₃COO⁻) crystal chemical group of uranyl complexes. It was found that compound II is isostructural to the (Rb_0.50Ba_0.25)[UO₂(CH₃COO)₃] studied earlier.     

Synthesis and crystal structure of (NH4)3[UO2(CH3COO)3]2[UO2(CH3COO)(NCS)2(H2O)]

Single crystals of the compound (NH₄)₃[UO₂(CH₃COO)₃]₂[UO₂(CH₃COO)(NCS)₂(H₂O)] (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 18.3414(6) ?, b = 16.3858(7) ?, c = 12.4183(5) ?, β = 92.992(1)°, space group C2/c, Z = 4, V = 3727.1(3) ?³, and R = 0.0253. The uranium-containing structural units of crystals I are mononuclear complexes of two types with an island structure, i.e., the [UO₂(CH₃COO)₃]⁻ anionic complexes belonging to the crystal-chemical group (AB ₃⁰¹ = UO₂²⁺, B ⁰¹ = CH₃COO⁻) of the uranyl complexes and the [UO₂(CH₃COO)(NCS)₂(H₂O)]⁻ anionic complexes belonging to the crystal-chemical group AB ⁰¹M₃¹ (A = UO₂²⁺, B ⁰¹ = CH₃COO⁻, M ¹ = NCS⁻ or H₂O).     

Crystal structure of M4[(UO2)2C2O4(SO4)2(NCS)2] ( M = K+, Rh+) and K4[(UO2)2C2O4(SeO4)2(NCS)2]

Three heteroacidoligand uranyl complexes M ₄[(UO₂)₂C₂O₄(SO₄)₂(NCS)₂] (M = K⁺ (I), Rb⁺ (II)) and K₄[(UO₂)₂C₂O₄(SeO₄)₂(NCS)₂] (III) have been synthesized and their crystal structure has been determined by X-ray diffraction analysis. The compounds I–III are isostructural and crystallized in the monoclinic system, sp. gr. P2₁/c, Z = 2, a = 11.5548(3) ?, b = 7.0847(1) ?, c = 13.5172(3) ?, β = 93.130(1)°, V = 1104.90(4), R = 0.015 (I); a = 11.5854(9) ?, b = 7.3841(6) ?, c = 13.9072(9) ?, β = 95.754(3)°, V = 1183.74(15), R = 0.0235 (II); a = 11.6715(3) ?, b = 7.1418(2) ?, c = 13.8546(1) ?, β = 93.539(1)°, V = 1152.66(5), R = 0.0126 (III). Basic structural units of these crystals are [(UO₂)₂C₂O₄(XO₄)₂(NCS)₂]⁴⁻ chains, which belong to the crystallochemical group A ₂ K ⁰² B ₂² M ₂¹ (A = UO₂²⁺, K ⁰² = C₂O₂₋⁴, B ² = SO₄²⁻ or SeO₄²⁻, M ¹ = NCS⁻) of uranyl complexes. Uranium-containing chains are connected into a 3D framework via a system of electrostatic interactions with potassium or rubidium cations from outer spheres. Original Russian Text ? I.V. Medrish, E.V. Peresypkina, A.V. Virovets, L.B. Serezhkina, 2008, published in Kristallografiya, 2008, Vol. 53, No. 3, pp. 495–498.     

Crystal structure of PbUO2(CH3COO)4(H2O)3

Single crystals of PbUO₂(CH₃COO)₄(H₂O)₃ have been investigated by X-ray diffraction (R = 0.029 for 3175 reflections). The structure of this compound is formed by [Pb(CH₃COO)(H₂O)₃]⁺ chains, which are oriented along the [100] axis and limited by one-core complexes [UO2(CH₃COO)₃]⁻. The coordination numbers of the Pb(II) and U(VI) atoms are 8, and the coordination polyhedron of uranium is a hexagonal bipyramid whose vertices contain oxygen atoms of three bidentate cyclic acetate groups and the uranyl group. Taking into account the different crystallographic roles of acetate ions, the crystal-chemical formula of [PbUO₂(CH₃COO)₄(H₂O)₃] chains can be written as AA′B ²¹ B ¹¹(B ⁰¹)₂ M ₃¹, where A = Pb; A′ = UO₂²⁺; M ¹ = H₂O; and B ²¹, B ¹¹, and B ⁰¹ are CH₃COO⁻ groups.     

Synthesis, characterization and crystal structure of [Ni(DACH)2](H2O)2(CH3COO)2 (DACH = 1,4-diazacycloheptane): a three-dimensional (3-D) hydrogen-bonded network embodying 1-D water chains

The mononuclear complex [Ni(DACH)₂](H₂O)₂(CH₃COO)₂ (DACH = 1,4-diazacyclo-heptane) has been synthesized and characterized by IR, UV-Vis, elemental analysis and single crystal X-ray diffraction. The complex crystallizes in monoclinic system, P2₁/n space group with a=7.500(3) ?, b=8.788(3) ?, c=16.429(6) ?, β=93.395(5)°, D _c =1.269 g cm⁻³, μ=0.930 mm⁻¹, V=1080.9(6) ?³, Z=2. The central Ni^II atom is in a square-planar coordination geometry formed by four N atoms of two DACH chelated ligands. The notable feature of the title compound resides in the formation of a three-dimensional network through hydrogen bonds between the [Ni(DACH)₂]²⁺ cations, the CH₃COO⁻ counter anions and the guest water molecules trapped in the crystal lattice.     

Synthesis and crystal structure of oxonitrate complexes Cs[VO2(NO3)2], Cs[MoO2(NO3)3], and MoO2(NO3)2

Cs[VO₂(NO₃)₂] (I), MoO₂(NO₃)₂ (II), and Cs[MoO₂(NO₃)₃] (III) complexes have been obtained by crystallization from nitric solutions and studied by single-crystal X-ray diffraction. Complexes I and II contain infinite zigzag chains of similar compositions, [VO₂(NO₃)₂]⁻ and [MoO₂(NO₃)₂], in which V and Mo atoms form, respectively, trigonal- and pentagonal-bipyramidal polyhedra. Each of these polyhedrons also contains one terminal and two bridge O atoms and two terminal NO₃ groups which are monodentate and bidentate in complexes I and II, respectively. Complex III has an island structure and consists of Cs⁺ cations and [MoO₂(NO₃)₃]⁻ anions, in which the Mo atom is surrounded by one bidentate NO₃ group and two monodentate NO₃ groups and two terminal O atoms in the cis-positions; oxygen atoms form a polyhedron in the form of distorted octahedron. According to the ab initio calculation of isolated MoO₂(NO₃)₂ molecules in the gas phase and solution, the coordination environment of the Mo atom, similarly to the Cr(VI) atom in CrO₂(NO₃)₂, is formed by two bidentate nitrate groups and two terminal O atoms (polyhedron- twisted trigonal prism).     

Crystal structure of bis[diethylenetriamine-N′-(3-propionato)-N, N′,N″,O,O′]dicopper(II) Diperchlorate, [Cu2(4-Dtmp)2](ClO4)2

A complex of copper(II) with the diethylenetriaminemonopripionate ligand [Cu₂(4-Dtmp)₂](ClO₄)₂ (I) is synthesized and characterized using X-ray diffraction. The crystals of compound I are monoclinic, a = 7.740(2) Å, b = 19.199(3) Å, c = 8.449(2) Å, β = 91.61(2)°, Z = 2, and space group P2₁/n. The structural units of crystal I are centrosymmetric dimeric cations and statistically disordered ClO ₄ ⁻ anions. In the cation, the copper atom is coordinated by three N atoms [mean Cu-N, 2.01(1) Å] and two O atoms [Cu-O, 2.134(6) Å and 1.958(7) Å] of the pentadentate bridging-chelate Dtmp ligand, which occupy vertices of the trigonal bipyramid. The binuclear cations are linked via centrosymmetric pairs of hydrogen bonds into ribbons aligned parallel to the a axis of the crystal. The ClO ₄ ⁻ anions form columns in the same direction. In the crystal, the cationic ribbons and anionic columns alternate in a chessboard fashion. __________ Translated from Kristallografiya, Vol. 50, No. 3, 2005, pp. 450–454. Original Russian Text Copyright ? 2005 by Antsyshkina, Sadikov, Poznyak, Sergienko.     

X-ray diffraction study of R2[UO2(C3H2O4)2] ·H2O (R = K or Rb)

Compounds K₂[UO₂(C₃H₂O₄)₂] · H₂O (I) and Rb₂[UO₂(C₃H₂O₄)₂] · H₂O (II) are synthesized and their crystal structures are determined by X-ray diffraction. The compounds crystallize in the monoclinic crystal system; for I, a = 7.1700(2) ?, b =12.3061(3) ?, c = 14.3080(4) ?, β = 95.831(2)°, space group P2₁/n, Z = 4, and R = 0.0275; for II, a = 7.1197(2) ?, b = 12.6433(4) ?, c = 14.6729(6) ?, β = 96.353(2)°, space group P2₁/n, Z = 4, and R = 0.0328. It is found that I and II are isostructural. The main structural units of the crystals are the [UO₂(C₃H₂O₄)₂]²⁻ chains, which belong to the AT ¹¹ B ⁰¹ (A = UO₂²⁺, T ¹¹, and B ⁰¹ = C₃H₂O₄²⁻) crystal chemical group of uranyl complexes. The chains and alkali metal ions R (R = K or Rb) are connected by electrostatic interactions and hydrogen bonds. Some specific structural features of [UO₂(C₃H₂O4)₂]²⁻ complex groups are discussed.     

Synthesis, spectroscopic characterisation and X-ray structure of [trans-Co(en)2(NO2)2]2(Cr2O7)

Dark red crystals of bis[trans-dinitrobis(ethylenediamine)cobalt(III)] dichromate, [trans-Co(en)₂(NO₂)₂]₂(Cr₂O₇) have been obtained by slowly allowing to mix the solutions of potassium dichromate and trans-dinitrobis(ethylenediamine)cobalt(III) nitrate in 1:2 molar ratio in aqueous medium. Elemental analyses and spectroscopic techniques (IR, UV/visible, ¹H and ¹³C NMR) were used for characterizing the complex salt. The complex salt crystallizes in the orthorhombic space group Fdd2 with unit cell dimensions a = 24.778(2) ?, b = 30.457(2) ?, c = 6.5364(5) ?, Z = 8, V = 4932.8(7) ?³, R₁ = 0.0617 and wR₂ = 0.1518. X-ray structure determination revealed an ionic structure consisting of cationic cobaltammine [trans-Co(en)₂(NO₂)₂]NO₃ and dichromate anion. It is the first crystal structure of this cation with a dianion.     

Reactions of triosmium clusters with indole: X-ray structures of [Os3(CO)10(μ-OH)(μ-OMeCO)] and [Os3(μ-H)(CO)10(μ-1, 2-η2-NC8H6)]

Treatment of [Os₃(CO)₁₂] with indole in presence of a methanolic solution of Me₃NO⋅2H₂O at 60^∘C afforded the previously reported compounds [(μ-H)Os₃(CO)₁₀(μ-OMe)] 2, [(μ-H)Os₃(CO)₁₀(μ-OH)] 3 and [Os₃(CO)₁₀(μ-OH)(μ-OMeCO)] 4 in 10, 5 and 20% yields, respectively. The reaction of [Os₃(CO)₁₀(MeCN)₂] with indole at room temperature gave [(μ-H)Os₃(CO)₁₀(μ-1,2-η²-NC₈H₆)] 5 in 40% yield. Compounds 4 and 5 have been characterized by single crystal X-ray diffraction studies. Compound 4 crystallizes in the monoclinic space group P2(1)/c with a = 23.1239(3), b = 9.8087(4), c = 16.9017(6) ?, β = 92.6998(14)^∘, Z = 8 and V = 3829.3(2) ?³ and 5 crystallizes in the monoclinic space group P2(1)/c with a = 9.009(3), b = 9.764(4), c = 24.906(6) ?, β = 93.452(14)^∘, Z = 4 and V = 2186.9(13) ?³. Compound 4 consists of an open cluster of three osmium atoms with the hydroxy and methoxycarbonyl ligands bridging the open Os–Os edge. Compound 5 consists of an isosceles triangle of osmium atoms with one elongated Os–Os edge which is bridged by the hydride and the indolyl ligands.     

Synthesis and Crystal Structure of Copper II and Silver I Complex with 1,4-diazabicyclo[2.2.2]octane[Cu(CBC)2(Dabco)(H2O)] n (1) and [Ag2(HBC)2(Dabco)] n (2)

Two 1D polymeric complex, [Cu(CBC)₂(Dabco)(H₂O)] _n (1) and [Ag₂(HBC)₂(Dabco)] _n (2) have been synthesized and characterized by X-ray single crystal analysis, where CBCH is p-chlorobenzoic acid, HBCH 2 is 2-hydroxybenzoic acid and Dabco is 1,4-diazabicyclo[2.2.2]octane. Complex 1 has been obtained in high yield by hydrothermal synthesis from CuO and CBCH and Dabco, and complex 2 has been obtain by evaporation of the solvent from silver salicylate and Dabco, 1 crystallizes in the orthorhombic space group Pmn2 ₁ with a = 24.3310(5) ?, b = 6.9050(6) ?, c = 5.9980(5) ?, Z = 2, V = 1007.70(4) ?³ and Dx = 1.657 g cm⁻³, 2 crystallizes in the monoclinic space group P2 ₁ /m with a = 10.292(3) ?, b = 6.913(2) ?, c = 14.417(4) ?, β = 95.660(5), Z = 2, V = 1020.8(5) ?³ and Dx = 1.959 g cm⁻³. The final R value is 0.0302 for 1323 measured reflections for 1 and the final R value is 0.0684 for 1545 measured reflections for 2. The atomic arrangement is built by infinite one-dimensional polymeric chain in both complexes. These chains are cross-linked by hydrogen bonds involving the coordinated water molecules to form a two-dimensional framework in complex 1.     

Crystal structure and phase transitions in the new crystals of [(CH3)2NH2]2CuCl4[(CH3)2NH2]Cl

Crystals grown from a solution of dimethylammonium and copper chlorides are studied using electron paramagnetic resonance (EPR) and X-ray diffraction. The dielectric properties of the crystals grown are measured. It is established that the crystals have the composition [(CH₃)₂NH₂]₂CuCl₄[(CH₃)₂NH₂]Cl and, in phase I at room temperature, are described by the orthorhombic space group Pna2₁ with the unit cell parameters a = 11.338 Å, b = 9.981 Å, and c = 15.675 Å. At temperatures of 279 K and 253 K, the crystals undergo jumpwise phase transitions into the incommensurate modulated ferroelectric phase II and commensurate modulated phase III, respectively. __________ Translated from Kristallografiya, Vol. 49, No. 1, 2004, pp. 92–100. Original Russian Text Copyright ? 2004 by Kirpichnikova, Pietraszko, Bednarski, Waplak, Sheleg. Dedicated to the 80th Birthday of L.A. Shuvalov     

X-Ray diffraction and IR-spectroscopic studies of UO2(n-C3H7COO)2(H2O)2 and Mg(H2O)6[UO2(n-C3H7COO)3]2

Single crystals of UO₂(n-C₃H₇COO)₂(H₂O)₂ (I) and Mg(H₂O)₆[UO₂(n-C₃H₇COO)₃]₂ (II) are synthesized. Their IR-spectroscopic and X-ray diffraction studies are performed. Crystals I are monoclinic, a = 9.8124(7) Å, b = 19.2394(14) Å, c = 12.9251(11) Å, β = 122.423(1)°, space group P2₁/c, Z = 6, and R = 0.0268. Crystals II are cubic, a = 15.6935(6) Å, space group $Pa\bar 3$ , Z = 4, and R = 0.0173. The main structural units of I and II are [UO₂(C₃H₇COO)₂(H₂O)₂] molecules and [UO₂(C₃H₇COO)₃]^? anionic complexes, respectively, which belong to AB ₂ ⁰¹ M ₂ ¹ (I) and AB ₃ ⁰¹ (II) crystal chemical groups of uranyl complexes (A = UO ₂ ²⁺ , B ⁰¹ = C₃H₇COO^?, and M ¹ = H₂O). A crystal chemical analysis of UO₂ L ₂ · nH₂O compounds, where L is a carboxylate ion, is performed.     

X-ray Crystal Structure of Trans -UO2(N(SiMe3)2)2(THF)2: One in a Series of Uranyl(VI) Complexes Supported by Bis(trimethylsilyl)amido Ligands

Abstract The title compound trans-UO₂(N(SiMe₃)₂)₂(THF)₂ (1) was synthesized and characterized by X-ray crystallography. The complex crystallizes in the monoclinic space group C2/c (#15) with lattice parameters a = 16.0771(5) ?, b = 13.1196(4) ?, c = 16.9391(6) ?, β = 116.853(1)°, V = 3187.61(18) ?³, Z = 4, D _calc = 1.532 g cm^-3. The six-coordinate uranium(VI) center adopts an all-trans octahedral geometry consisting of mutually trans oxo groups, silylamido ligands, and neutral THF donors. Structural comparisons of this uranyl(VI) bis(amido) complex with a related tris(amido) derivative within the series are made based on symmetry, charge, and coordination number. Graphical Abstract The X-ray crystal structure of the title complex is reported, providing comparisons based on symmetry, charge, and coordination number with a related uranyl(VI) amido derivative within this series.      

Palladium (II) compounds with diaminocarboxylic acids: Crystal structures of [Pd(H2Cdta)] · H2O, [Pd(H3Edtp)Cl] · 2H2O, and (H6Edtp)[PdCl4] · 4H2O

The crystal structures of three Pd(II) compounds with diamine tetracarboxylates in different protonation states are determined, namely, [Pd(H₂ Cdta)] · H₂O (I), [Pd(H₃ EdtpCl] · 2H₂O (II), and (H₆ Edtp)[PdCl₄] · 4H₂O (III) (R ₁ = 0.0230, 0.0313, and 0.0277 for 3040, 3377, and 3809 reflections with I > 2σ(I) for I–III, respectively). Crystals I and II are built of neutral complexes [Pd(H₂ Cdta)] and [Pd(H₃ Edtp)Cl], respectively, and crystallization water molecules. Crystal III consists of [PdCl₄]²⁻ anionic complexes, H₆ Edtp ²⁺ cations, and water molecules. In I, one of the protonated acetate groups of the H₂ Cdta ²⁻ ligand forms a very weak additional Pd-O bond [2.968(2) Å] over the 2N + 2O coordination square. In II and III, the protonated propionate groups of the H₃ Edtp ⁻ ligand and the H₆ Edtp ²⁺ cation are not involved in Pd coordination and the coordination squares consist of the 2N + O + Cl and 4Cl atoms, respectively. __________ Translated from Kristallografiya, Vol. 48, No. 2, 2003, pp. 278–282. Original Russian Text Copyright ? 2003 by Polyakova, Poznyak, Sergienko.     

A Novel Three Dimensional Organic–Inorganic Hybrid Based Porous Phase: Synthesis and Characterization of Reduced Oxovanadium pyromellitate, [VIV2O2(H2O)2(C6H2(COO)4)]

The hydrothermal reaction of a mixture of VOSO₄ · xH₂O, 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid) and 0.1 M H₂SO₄ for 72 h at 160 °C gives blue needle like crystals of [V^IV ₂O₂(H₂O)₂(C₆H₂(COO)₄)] in 30% yield. The compound has a porous 3-D extended network structure having a rigid architecture which is held together by the multidentate functionalities of 1,2,4,5-benzenetetracarboxylate ligand. Crystal data for the compound: monoclinic space group C 2/c (No:15), a = 11.756(5) ?, b = 9.645(3) ?, c = 11.822(7) ?, β = 107.10(4)°, Z = 8. The compound constitutes the first example of a fully reduced oxovanadium based solid incorporating the organic ligand. This article consists of synthesis, crystal structure and characterization of [V^IV ₂O₂(H₂O)₂(C₆H₂(COO)₄)].     

Synthesis and crystal structure of Cu3(Bipy)2(L1)2(L2)2? 4H2O(Bipy = 2,2′-bipyridine, L1 =1-((2-sulfonateethylimino)methyl)-2-naphthol), L2 = 2-hydroxy-1-naphthaldehyde)

The title compound, Cu₃(Bipy)₂(L¹)₂(L²)₂⋅4H₂O, was synthesized in the methanol solution of Bipy and Cu(II) in the presence of 1-((2-sulfonate-ethylimino)-methyl)-2-naphthol (L¹), which was condensation compound of taurine and 2-hydroxy-1-naphthaldehyde. This complex crystallized in the space group P-1 with a = 9.825(2) ?, b = 12.626(2) ?, c = 14.342(3) ?, α = 90.29(1)^∘, β = 100.67(1)^∘, γ = 101.67(2)^∘, and Z = 2. In the trinuclear Cu(II) complex, there are two type Cu atoms which have square and square pyramid geometries, respectively. The Cu–N distances vary from 1.965(3) to 2.000(4) ?, while the Cu–O distances are between 1.896(3) and 2.337(4) ?.     

Synthesis and X-ray structural investigation of K2(H5O2)[UO2(C2O4)2(HSeO3)]

The synthesis and X-ray diffraction analysis of K₂(H₅O₂)[UO₂(C₂O₄)₂(HSeO₃)] single crystals have been performed. This compound crystallizes in the triclinic system with the unit-cell parameters a = 6.7665(4) ?, b = 8.8850(4) ?, c = 12.3147(7) ?, α = 94.73°, β = 90.16°, γ = 92.11°, sp. gr. P[`1]P\bar 1, Z = 2, and R = 0.019. The basic structural units are island [UO₂(C₂O₄)₂(HSeO₃)]³⁻ groups, which belong to the AB ₂⁰¹ M ¹ crystallochemical group of uranyl complexes (A = UO₂²⁺, B ⁰¹ = C₂O₄²⁻, and M ₁ = HSeO₃⁻). Uraniumcontaining complexes are linked through K⁺ and H₅O₂⁺ ions and via a system of hydrogen bonds with the participation of oxonium hydrogen atoms in this structure.     

Synthesis and Characterization of Nickel(II) Complex of 3,14-Dimethyl-2,6,13,17-Tetraazatricyclo[14,4,01.18,07.12]Docosane Containing Pyrazine-2-Carboxylate Ligand

Abstract  

The reaction of [Ni(L)]Cl₂·2H₂O (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane) with pyrazine-2-carboxylic acid (H-pyc) yields mononuclear nickel(II) complex, [Ni(L)(pyc)₂]·2H₂O (1). This complex has been characterized by X-ray crystallography, electronic absorption and cyclic voltammetry. The crystal structure of 1 exhibits a distorted octahedral geometry with four nitrogen atoms of the macrocycle and two pyrazine-2-carboxylate ligands. It crystallizes in the triclinic system P-1 with a = 9.6643(17), b = 10.116(3), c = 16.99(4) ?, V = 1633(3) ?³, Z = 2. Electronic spectrum of 1 also reveals a high-spin octahedral environment. Cyclic voltammetry of 1 undergoes two waves of a one-electron transfer corresponding to Ni^II/Ni^III and Ni^II/Ni^I processes.     

Synthesis and X-ray structural investigation of (C3N6H7)4(CN3H6)2[UO2(CrO4)4] · 4H2O and (H3O)6[UO2(CrO4)4]

Single crystals of the compounds (C₃N₆ H₇)₄(CN₃H₆)₂[UO₂(CrO₄)₄] · 4H₂O (I) and (H₃O)₆[UO₂(CrO₄)₄] (II) are synthesized, and their structures are investigated using X-ray diffraction. Compound I crystallizes in the triclinic system with the unit cell parameters a = 6.3951(8) ?, b = 10.8187(16) ?, c = 16.9709(18) ?, α = 93.674(4)°, β = 97.127(4)°, γ = 92.020(4)°, space group, P Z = 1, V = 1161.6(3) ?³, and R = 0.0470. Crystals of compound II belong to the monoclinic system with the unit cell parameters a = 14.3158(4) ?, b = 11.7477(3) ?, c = 13.1351(4) ?, β= 105.836(1)°, space group C2/c, Z = 4, V = 2125.2(1) ?³, and R = 0.0213. The uranium-containing structural units of crystals I and II are mononuclear anionic complexes of the composition [UO₂(CrO₄)₄]⁶⁻ with an island structure, which belong to the crystal-chemical group Am ₁⁴ (A = UO₂₊², M ¹ = CrO₂₋⁴) of the uranyl complexes. The [UO₂(CrO₄)₄]⁶⁻ anionic complexes are joined into a three-dimensional framework through the electrostatic interactions with outer-sphere cations and a system of hydrogen bonds. Original Russian Text ? L.B. Serezhkina, E.V. Peresypkina, A.V. Virovets, A.G. Verevkin, D.V. Pushkin, 2009, published in Kristallografiya, 2009, Vol. 54, No. 2, pp. 284–290.