A new refinement of the crystal structure of the inverse weberite Fe2F5(H2O)2

Fe₂F₅(H₂O)₂ is related to the weberite structure, whose space group is not clearly defined. A careful reexamination of the structure confirms and refines the previous results: Fe₂F₅(H₂O)₂ belongs to the space group Imma with cell parameters a = 7.477(1) Å, b = 10.862(2) Å, c = 6.652(1) Å (Z = 4). The structure has been refined from 379 reflections to R = 0.029 (R_w = 0.034). Fe₂F₅(H₂O)₂ must be considered as an antiweberite structure since M²⁺ and M³⁺ positions are inverse of those of the weberite structure.     

Idle spin behavior of the shifted hexagonal tungsten bronze type compounds FeIIFeIII2F8(H2O)2 and MnFe2F8(H2O)2

Fe^IIFe^III₂F₈(H₂O)₂ and MnFe₂F₈(H₂O)₂, grown by hydrothermal synthesis ($\text{P ? 200}\text{MPa}\text{, T = 450}\text{or}\text{380°}\text{C}$), crystallize in the monoclinic system with cell dimensions (Å): a = 7.609(5), b = 7.514(6), c = 7.453(4), β = 118.21(3)°; and a = 7.589(6), b = 7.503(8), c = 7.449(5), β = 118.06(3)°, and space group $\text{C2}\text{m}\text{, Z = 2}$. The structure is related to that of $\text{WO}{}_3\text{·}\text{1}\text{3}\text{H}{}_2\text{O}$. It is described in terms of perovskite type layers of Fe³⁺ octahedra separated by Fe²⁺ or Mn²⁺ octahedra, or in terms of shifted hexagonal bronze type layers. Both compounds present a weak ferromagnetism below T_N (157 and 156 K, respectively). Mössbauer spectroscopy points to an “idle spin” behavior for Fe^IIFe^III₂F₈(H₂O)₂: only Fe³⁺ spins order at T_N, while the Fe²⁺ spins remain paramagnetic between 157 and 35 K. Below 35 K, the hyperfine magnetic field at the Fe²⁺ nuclei is very weak: H_hf = 47 kOe at T = 4.2 K. For MnFe₂F₈(H₂O)₂, Mn²⁺ spin disorder is expected at 4.2 K. This “idle spin” behavior is due to magnetic frustration.     

Syntheses of the linkage isomers (H2O)5CrNCCo(CN)5 and (H2O)5CrCNCo(CN)5

The slow reaction of Cr(H₂O)₆³⁺ with Co(CN)₆³⁻ produces (H₂O)CrNCCo(CN)₅. The rapid reaction of Co(CN)₅N₃³⁻ with nitrious acid in the presence of Cr)OH₂)₅CN²⁺ produces (H₂O)₅CrCNCo(CN)₅. The two binuclear complexes were separated and purified by cation and anion exchange procedures. The orientation of the bridging cyanide in the isomeric complexes was determined by a spectroscopic technique. For (H₂O)₅CrNCCo(CN)₅ the ⁴A_2g → ⁴T_2g and ⁴A_2g → ⁴T_1g of the chromium moiety are at 560 and 401 nm, respectively, and the ¹A_1g → ¹T_1g of the cobalt moiety is at 310 nm. For (H₂O)₅CrCNCo(CN)₅ the ⁴A_2g → ⁴T_2g band is at 552 nm, but the ⁴A_2g → ⁴T_1g absorption of the chromium is obscured by the ¹A_1g → ¹T_1g transition of the cobalt at 347 nm. The base hydrolysis of (H₂O)₅CNCCo(CN)₅ produces Co(CN)₆³⁻ and “chromite” quantitatively. The vase hydrolysis of (H₂O)₅CrCNCo(CN)₅ produces chromite and an unidentified cobalt(III) species that absorbs at 345–347 nm.     

Cs2.91Na1.34Fe3+0.25[Fe3O(SO4)6(H2O)3]·5H2O,a member of the Maus's salt family

The title compound, tricaesium sodium iron(III) μ₃‐oxido‐hexa‐μ₂‐sulfato‐tris[aquairon(III)] pentahydrate, Cs_2.91Na_1.34Fe³⁺_0.25[Fe₃O(SO₄)₆(H₂O)₃]·5H₂O, belongs to the family of Maus's salts, K₅[Fe₃O(SO₄)₆(H₂O)₃]·6H₂O, which is based on the triaqua‐μ₃‐oxido‐hexa‐μ‐sulfato‐triferrate(III) anion, [Fe₃O(SO₄)₆(H₂O)₃]⁵⁻, with Fe in a characteristically distorted octahedral coordination environment, sharing a common corner via an oxide O atom. Cs in four different cation sites, Na in three different cation sites and five water molecules link the anions in three dimensions and set up a crystal structure in which those parts parallel to (001) and within 0.05 < z < 0.95 have a distinct trigonal pseudosymmetry, whereas the cation arrangement and bonding near z∼ 0 generate a clear‐cut noncentrosymmetric polar edifice with the monoclinic space group C2. The structure shows some cation disorder in the region near z ∼ , where one Na atom in octahedral coordination is partly substituted by Fe³⁺, and a Cs atom is substituted by small amounts of Na on a separate nearby site. One Na atom, located on a twofold axis at z = 0 and tetrahedrally coordinated by four sulfate O atoms of two [Fe₃O(SO₄)₆(H₂O)₃]⁵⁻ units, plays a key role in generating the noncentrosymmetric structure. Three of the seven different cation sites are on twofold axes (one Na⁺ site and two Cs⁺ sites), and all other atoms of the structure are in general positions.     

Optical,thermal, and magnetic properties of a microporous fluorinated iron phosphate: (H3O)2[Fe4(H2O)2F4(PO4)2(HPO4)2](H2O)

The non-centrosymmetric microporous fluorinated iron phosphate, (H₃O)₂[Fe₄(H₂O)₂F₄(PO₄)₂(HPO₄)₂](H₂O), is endowed with properties. In fact, the thermogravimetric analysis study shows a mass loss evolution as a temperature function. The optical study was also examined by UV–vis absorption. The magnetic results reveal the appearance of a ferromagnetic behavior at low temperature (Tc = 11.64 K).     

Double complexes [Co(NH3)5(H2O)]2[Zr3F18]·6H2O and [Co(NH3)6]2[Zr3F18]·6H2O

The structures of orthorhombic bis[pentaammineaquacobalt(III)] tetra‐μ₂‐fluorido‐tetradecafluoridotrizirconium(IV) hexahydrate (space group Ibam), [Co(NH₃)₅(H₂O)]₂[Zr₃F₁₈]·6H₂O, (I), and bis[hexaamminecobalt(III)] tetra‐μ₂‐fluorido‐tetradecafluoridotrizirconium(IV) hexahydrate (space group Pnna), [Co(NH₃)₆]₂[Zr₃F₁₈]·6H₂O, (II), consist of complex [Co(NH₃)_x(H₂O)_y]³⁺ cations with either m [in (I)] or and 2 [in (II)] symmetry, [Zr₃F₁₈]⁶⁻ anionic chains located on sites with 222 [in (I)] or 2 [in (II)] symmetry, and water molecules.     

Studies on the non-isothermal kinetics of thermal decomposition of the mixed ligand complex — [Fe2O(OC6H4CH=NC6H4O)2(C5H5N)4]·2H2O

The thermal decomposition of the mixed-ligand complex of iron(III) with 2-[(o-hydroxy benzylidene)amino] phenol and pyridine-[Fe₂O(OC₆H₄CH=NC₆H₄O)₂(C₅H₅N)₄]·2H₂O and its non-isothermal kinetics were studied by TG and DTG techniques. The non-isothermal kinetic data were analyzed and the kinetic parameters for the first and second steps of the thermal decomposition were evaluated by two different methods, the Achar and Coats-Redfern methods. Steps 1 and 2 are both second-order chemical reactions. Their kinetic equations can be expressed as: dα/dt=Ae^?E/RT(1-α)²     

Die Kristallstruktur des gemischtvalenten Eisenfluoridhydrates Fe3F8 · 2 H2O

Crystal Structure of the Mixed-Valence Iron Fluorid Hydrate Fe₃F₈ · 2 H₂O Newly prepared was the red, monoclinic compound Fe₃F₈ · 2 H₂O, single crystals of which could be obtained under hydrothermal high pressure conditions (space group C2/m with a = 761.2(3), b = 750.0(1), c = 746.9(3) pm, β = 118.38(2)° and Z = 2). The X-ray structure determination (R_G = 0.0192 and 635 reflexions) yielded a framework structure, in which layers of octahedra 2[Fe^IIIF_6/2] are connected via corners of [Fe^IIF_4/2(H₂O)₂]-octahedra. The average distances in the nearly ideal octahedra are Fe^III? F = 193.0, Fe^II? F = 208.1 and Fe^II? OH₂ = 211.5 pm.     

Oxyfluorinated compounds with an open structure XVI. Synthesis,structure determination and magnetic properties of Fe4F3(PO4)(HPO4)4(H2O)4(N2C3H12) [ULM-15]

Fe₄F₃(PO₄)(HPO₄)₄(H₂O)₄(N₂C₃H₁₂) (labelled ULM-15) was prepared hydrothermally (7 days, 453 K, autogenous pressure) in the presence of 1,3-diaminopropane as organic template. Its structure was determined by single crystal X-ray diffraction. ULM-15 is monoclinic (Space group C2/c (no 15)) with lattice parameters a = 24.176(1) , b = 14.558(1) , c = 7.186(1) , β = 102.3(1)°, V = 2470.8(3) ³, Z = 4. Its three-dimensional framework is constituted from corner-sharing FeX₆ (X = O, F, H₂O) octahedra and tetrahedral PO₄ and HPO₄ groups. The structure presents trans-chains of FeO₄F₂ octahedra related to ferric dimers [Fe₂O₈F₂(H₂O)₂] by tetrahedral units. They delimit 16-membered rings channels along [001] in which the diprotonated amines are inserted. ULM-15 shows 3D antiferromagnetic behaviour below T_N ≈ 22 K.     

Syntheses and structures of nine-coordinate K3[DyIII(nta)2(H2O)]·5H2O and eight-coordinate (NH4)3[DyIII(nta)2] complexes

K₃[Dy^III(nta)₂(H₂O)]·5H₂O and (NH₄)₃[Dy^III(nta)₂] have been synthesized in aqueous solution and characterized by IR, elemental analysis and single-crystal X-ray diffraction techniques. In K₃[Dy^III(nta)₂(H₂O)]·5H₂O the Dy^III ion is nine coordinated yielding a tricapped trigonal prismatic conformation, and its crystal belongs to monoclinic system and C2/c space group. The crystal data are as follows: a = 15.373(5) Å, b = 12.896(4) Å, c = 26.202(9) Å; β = 96.122(5)°, V = 5165(3) ų, Z = 8, D _c = 1.965 g·cm^?3, μ = 3.458 mm^?1, F(000) = 3016, R ₁ = 0.0452 and wR ₂ = 0.1025 for 4550 observed reflections with I ≥ 2σ(I). In (NH₄)₃[Dy^III(nta)₂] the Dy^III ion is eight coordinated yielding a usual dicapped trigonal anti-prismatic conformation, and its crystal belongs to monoclinic system and C2/c space group. The crystal data are as follows: a = 13.736(3) Å, b = 7.9389(16) Å, c = 18.781(4) Å; β = 104.099(3)°, V = 1986.3(7) ų, Z = 2, D _c = 1.983 g·cm^?3, μ = 3.834 mm^?1, F(000) = 1172, R ₁ = 0.0208 and wR ₂ = 0.0500 for 2022 observed reflections with I ≥ 2σ(I). The results indicate that the difference in counter ion also influences coordination numbers and structures of rare earth metal complexes with aminopolycarboxylic acid ligands.     

Synthesis and Crystal Structure of Europium(II) Tartrate Tetrahydrate, [Eu(C4H4O6)(H2O)2](H2O)2

Single crystals of [Eu(C₄H₄O₆)(H₂O)₂](H₂O)₂ were obtained from the combination of solutions of EuCl₂, previously obtained by electrolysis of an aqueous solution of EuCl₃, and tartraric acid, neutralized by LiOH. The crystal structure (orthorhombic, P2₁2₁2₁, Z = 4, a = 948.9(1), b = 954.6(1), c = 1098.4(1) pm; R(F) = 0.0242 and R_w(F²) = 0.0585 for I > 2σ(I); R(F) = 0.0256 and R_w(F²) = 0.0592 for all data) is isotypic with [Ca(C₄H₄O₆)(H₂O)₂](H₂O)₂ and [Sr(C₄H₄O₆)(H₂O)₂](H₂O)₂ exhibiting a three‐dimensional structure. The divalent cations (Eu²⁺, Ca²⁺, Sr²⁺) are eight‐coordinate by oxygen atoms that originate from carboxylate and hydroxyl groups of the tartraric dianion and two of the four water molecules.     

[{Er(NC5H4COOH)(H2O)2}2(H5O2)(HgCl5)(HgCl4)2(H2O)2]n – Synthesis,Crystal Structure and Properties

The first heterometallic 4f‐5d inorganic‐organic metal‐isonicotinic acid hybrid [{Er(NC₅H₄COOH)(H₂O)₂}₂(H₅O₂)(HgCl₅)(HgCl₄)₂(H₂O)₂]_n ( 1 ) has been synthesized via hydrothermal reaction and structurally characterized. Complex 1 crystallizes in the space group C2/c of the monoclinic system with four formula units per unit cell: a = 24.194(3), b = 20.792(3), c = 15.289(4) Å, β = 128.39(2)°, V = 6028(2) ų, C₃₆H₄₇Cl₁₃Er₂Hg₃N₆O₂₀, M_r = 2280.94, D_c = 2.513 g/cm³, S = 0.929, μ(MoKα) = 11.017 mm^?1, F(000) = 4248, R = 0.0425 and wR = 0.0739. The crystal structure analysis reveals that the title complex is characteristic of a one‐dimensional chain‐like structure. Photoluminescent investigation reveals that the title complex displays interesting emissions. Optical absorption spectra of 1 reveal the presence of an optical gap of 3.45 eV. The magnetic properties show that complex 1 exhibits antiferromagnetic interactions.     

Thermal and spectral studies of 5-(phenylazo)-2-thiohydantoin and 5-(2- hydroxyphenylazo)-2-thiohydantoin complexes of cobalt(II), nickel(II) and copper(II)

Complexes of 5-(phenylazo)-2-thiohydantoin (L¹) and 5-(2-hydroxyphenylazo)-2-thiohydantoin (HL²) with Co(II), Ni(II) and Cu(II) salts have been synthesised and characterized by elemental analysis, conductivity, magnetic susceptibility, UV-Vis, IR, ESR and TG studies. The magnetic and spectral data suggested octahedral geometry for [L¹M(OAc)₂(H₂O)₂]·xH₂O {M=Ni^ll and Cu^ll} and [L¹CuCl₂(H₂O)]·H₂O (dimeric form for the latter), trigonal bipyramidal geometry for [L²Co(OAc)(H₂O)]·2H₂O, square pyramidal geometry for [L²Ni(OAc)(H₂O)]·H₂O and square planar geometry for [L²CuCl]·2H₂O. TG studies confirmed the chemical formulations of these complexes and showed that their thermal degradation takes place in three to five steps, depending on the type of the ligand and the geometry of the complex. The kinetic parameters (n, E^#, A, ΔH^#, ΔS^# and ΔG^#) of the thermal decomposition stages were computed using the Coats-Redfern and other standard equations and are discussed.     

Electrochemistry of the iron-sulfur cluster compound [(η-C5H5)2Fe2S2(SC2H5)2]. Synthesis and propeties of the oxidation products

In order to gain some insight into the stability of configuration and the bonding in the novel disulfide-containing complex [(η-C₅H₅)₂Fe₂S₂(SC₂H₅)₂], electrochemical properties of this compound and its SCH₃ and SCH₂C₆H₅ analogues were studied in various solvents and the magnetic properties of a subsequently isolated paramagnetic monocation were investigated. The cyclic voltammogram of [(η-C₅H₅)₂Fe₂S₂(SC₂H₅)₂] shows a reversible one-electron oxidation at E_{$\text{1}\text{2}$}= +0.21 V and a quasi-reversible one-electron oxidation at E_{$\text{1}\text{2}$} = +0.90 V (vs.saturated calomel electrode). The stable monocation has been electrochemically synthesized and the magnetic suceptibility shows a simple paramagnetic behavior with one unpaired electron per dimeric unit. Frozen solutions of this species at 103K yielded anisotropic ESR spectra with g₁ = 2.135, g₂ = 1.976, and g₃ = 1.934. Labeling the complex with ³³S in the disulfide bridge resulted in no observable hyperfine splitting or line broadening in the ESR. The dicationic species is unstable with respect to loss of the S₂ bridge and formation of a solvent-ligated dication, [(η-C₅H₅)Fe(NCCH₃)(SC₂H₅)]₂²⁺, isolated by electrolysis of the monocation at +1.2 V in CH₃CN.     

Über die Struktur vonM(BF4)2·6H2O fürM=Mg2+, Zn2+, Cd2+

The IR and Raman spectra ofM(BF₄)₂·6H₂O forM=Mg²⁺, Zn²⁺ and Cd²⁺ in the range 4000–140 cm^?1 were recorded, as were theirDTA andTG curves up to 500°C. The data obtained confirm the presence of the water complex [M(H₂O)₆]²⁺ and of the complex anion BF₄ ^? in these compounds. It was also established that the six water molecules in Mg(BF₄)₂·6H₂O and in Zn(BF₄)₂·6H₂O are not crystallographically equivalent, and that hydrogen bonds of the type H₂O...H₂O...F₄B and H₂O...H₂O...H₂O participate in the structure. The energy of the hydrogen bonds H₂O...F₄B for the three crystal hydrates was also calculated. The thermal and thermogravimetric data are in agreement with and confirm the spectroscopic data.     

Slow Magnetic Relaxation,Antiferromagnetic Ordering,and Metamagnetism in MnII(H2dapsc)-FeIII(CN)6 Chain Complex with Highly Anisotropic Fe-CN-Mn Spin Coupling

Reactions of [Mn(H₂dapsc)Cl₂] ⋅ H₂O (dapsc=2,6- diacetylpyridine bis(semicarbazone)) with K₃[Fe(CN)₆] and (PPh₄)₃[Fe(CN)₆] lead to the formation of the chain polymeric complex {[Mn(H₂dapsc)][Fe(CN)₆][K(H₂O)_3.5]}_n ⋅ 1.5n H₂O ( 1 ) and the discrete pentanuclear complex {[Mn(H₂dapsc)]₃[Fe(CN)₆]₂(H₂O)₂} ⋅ 4 CH₃OH ⋅ 3.4 H₂O ( 2 ), respectively. In the crystal structure of 1 the high-spin [Mn^II(H₂dapsc)]²⁺ cations and low-spin hexacyanoferrate(III) anions are assembled into alternating heterometallic cyano-bridged chains. The K⁺ ions are located between the chains and are coordinated by oxygen atoms of the H₂dapsc ligand and water molecules. The magnetic structure of 1 is built from ferrimagnetic chains, which are antiferromagnetically coupled. The complex exhibits metamagnetism and frequency-dependent ac magnetic susceptibility, indicating single-chain magnetic behavior with a Mydosh-parameter φ=0.12 and an effective energy barrier (U_eff/k_B) of 36.0 K with τ₀=2.34×10⁻¹¹ s for the spin relaxation. Detailed theoretical analysis showed highly anisotropic intra-chain spin coupling between [Fe^III(CN)₆]³⁻ and [Mn^II(H₂dapsc)]²⁺ units resulting from orbital degeneracy and unquenched orbital momentum of [Fe^III(CN)₆]³⁻ complexes. The origin of the metamagnetic transition is discussed in terms of strong magnetic anisotropy and weak AF interchain spin coupling.     

Synthesis and structure of copper(II) trans-diaqua-bis(3-hydroxybenzoylhydrazine) nitrate dihydrate [Cu(C7H8O2N2)2(OH2)2](NO3)22H2O

Synthesis of [Cu(m-HBH)₂(OH₂)₂](NO₃)₂·2H₂O, where m-HBH = C₇H₈O₂N₂ (3-hydroxybenzoylhydrazine), is described. The structure of the compound was studied by X-ray phase analysis and IR spectroscopy; crystal data are a = 57.415(6) Å, b = 19.760(2) Å, c = 7.586(2) Å; Fdd 2, Z = 16, R(F) = 0.053. The compound consists of [Cu(m-HBH)₂(OH₂)₂]²⁺ complex cations, NO ₃ ^? anions, and two water molecules. The similarity between the IR spectra of Cu(m-HBH)₂(NO₃)₂·nH₂O and Co(m-HBH)₂(NO₃)₂·5H₂O, element analysis data, and crystal data obtained at the first stage of X-ray analysis show that the structures and compositions of these compounds are identical relative to the type of surroundings of the central atom. In contrast to the cobalt compound [Co(m-HBH)₂(OH₂)₂](NO₃)₂·3H₂O, in which the cobalt atom has a nearly regular octahedron as a coordination polyhedron, the copper(II) compound has a square bipyramid around the copper atom; c.n. is 6 = 4 + 2 (planar distances: 2.013(2) Å, 2.021(2) Å, 2.033(3) Å, 2.087(3) Å; axial distances: 2.367(3) Å, 2.374(3) Å) and lacks one crystallization water molecule.     

Ein- und zweikernige Fluorokomplexe des Titan(III), Chrom(III) und Eisen(III) Darstellung und Struktur von (NMe4)(Ti(H2O)4F2)TiF6 · H2O, (NMe4)3Cr2F9 und (NMe4)3Fe2F9

Mono- and Dinuclear Fluoro Complexes of Titanium (III), Chromium (III), and Iron(III). Syntheses and Structures of (NMe₄) (Ti(H₂O)₄F₂)TiF₆ · H₂O, (NMe₄)₃Cr₂F₉, and (NMe₄)₃Fe₂F₉ The title compounds have been prepared by reaction of MCl₃ (M = Ti, Cr, Fe) with NMe₄F in dimethylformamide. (NMe₄)₃Cr₂F₉ and (NMe₄)₃Fe₂F₉ contain the face-sharing biocathedral M₂F₉^3? unit. The M…M distances are 277.1(1) and 289.8(3) pm in (NMe₄)₃Cr₂F₉ and (NMe₄)Fe₂F₉, respectively. (NMe₄)(Ti(H₂O)₄F₂)TiF₆ · H₂O contains trans-Ti^III(H₂O)₄F₂⁺ cations and Ti^IVF₆^2? anions. Crystal data: (NMe₄)₃Cr₂F₉: hexagonal, space group P6₃/m, a = 804.1(3), c = 1857.5(4) pm, Z = 2, 529 reflections, R = 0.049; (NMe₄)₃Fe₂F₉: hexagonal, space group P6₃/m, a = 804.7(5), c = 1 861.6(5) pm, Z = 2, 635 reflections, R = 0,046; (NMe₄)(Ti(H₂O)₄F₂)TiF₆ · H₂O: orthorhombic, space group Pbca, a = 776.9(2), b = 1 616.3(3), c = 2 428.6(7) pm, Z = 8, 2 784 reflections, R = 0,056.     

Synthesis,Crystal Structure and Magnetic Behaviour of the new Tetrameric Gadolinium Carboxylate [Gd4(OH)4(CF3COO)8(H2O)4] · 2.5 H2O

The novel tetrameric gadolinium(III) compound [Gd₄(OH)₄(CF₃COO)₈(H₂O)₄] · 2.5 H₂O was synthesized and structurally characterized by X‐ray crystallography. The Gd³⁺ ions are bridged by hydroxide ions and carboxylate groups to tetramers with Gd³⁺‐Gd³⁺ distances between 384.2(2) and 388.1(2) pm. The compound crystallizes in the monoclinic space group C2/c (Z = 4). The magnetic behaviour of [Gd₄(OH)₄(CF₃COO)₈(H₂O)₄] · 2.5 H₂O was investigated in the temperature range of 2 to 300 K. The magnetic data of this compound indicate antiferromagnetic interactions (J_ex = ?0.0197 cm^?1).     

Crystal structure of (C2H7N4O)2[UO2(C2O4)2(H2O)]

The single crystals of (C₂H₇N₄O)₂[UO₂(C₂O₄)₂(H₂O)] were studied by X-ray diffraction. The crystals are monoclinic, space group Pn, Z = 2, unit cell parameters: a = 9.4123(2) Å, b = 8.4591(2) Å, c = 11.8740(3) Å, β = 105.500(10)°, V = 911.02(4) ų. The main structural units of the crystals of I are islet complex groups [UO₂(C₂O₄)₂(H₂O)]^2? corresponding to the crystal chemical group AB ₂ ⁰¹ M¹ (A = UO UO ₂ ²⁺ , B⁰¹ = C₂O ₄ ^2? , M = H₂O) of uranyl complexes. Uranium-containing mononuclear complexes are connected into a three-dimensional framework through the electrostatic interactions and hydrogen bonding system involving carbamyolguanidinium ions.