The Crystal Structure of Ianthinite, a Mixed-Valence Uranium Oxide Hydrate

1996 ◽  
Vol 465 ◽  
Author(s):  
Peter C. Burns ◽  
Robert J. Finck ◽  
Frank C. Hawthorne ◽  
Mark L. Miller ◽  
Rodney C. Ewing
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Uranium Oxide ◽  
Spent Nuclear Fuel ◽  
Mixed Valence ◽  
Direct Methods ◽  
Crystal Chemical ◽  
Uranyl Ions ◽  
Oxide Hydrate ◽  
Distorted Octahedral

ABSTRACTIanthinite, [U4+2(UO2)4O6(OH)4(H2O)4](H2O)5, is the only known uranyl oxide hydrate mineral that contains U4+, and it has been proposed that ianthinite may be an important Pu4+-bearing phase during the oxidative dissolution of spent nuclear fuel. The crystal structure of ianthinite, orthorhombic,a7.178(2),b11.473(2),c.30.39(1) Å,V2502.7 Å3,Z= 4, space groupP21cn, has been solved by direct methods and refined by least-squares methods to anRindex of 9.7 % and awRindex of 12.6 % using 888 unique observed [ | F | ≥ 5σ | F | ] reflections. The structure contains both U6+and U4+. The U6+cations are present as roughly linear (U6+O2)2+uranyl ions (Ur) that are in turn coordinated by five O2-and OH located at the equatorial positions of pentagonal bipyramids. The U4+cations are coordinated by O2-, OH and H2O in a distorted octahedral arrangement. TheUrφ5and U4+φ6(φ: O2-, OH, H2O) polyhedra link by sharing edges to form two symmetrically distinct sheets atzz ≈ 0.0 and z ≈ 0.25 that are parallel to (001). The sheets have the β-U3O8sheet anion-topology. There are five symmetrically distinct H2O groups located at z ≈ 0.125 between the sheets of Uφnpolyhedra, and the sheets of Uφnpolyhedra are linked together only by hydrogen bonding to the intersheet H2O groups. The crystal-chemical requirements of U4+and Pu4+are very similar, indicating that extensive Pu4+↔ U4+substitution can occur within the sheets of Uφnpolyhedra in the structure of ianthinite.

Description and Classification of Uranium Oxide Hydrate Sheet Topologies

1995 ◽  
Vol 412 ◽  
Author(s):  
M. L. Miller ◽  
R. J. Finch ◽  
P. C. Burns ◽  
R. C. Ewing
Keyword(s):  
Thermodynamic Parameters ◽  
Structural Unit ◽  
Uranium Oxide ◽  
Spent Nuclear Fuel ◽  
Structural Similarity ◽  
Zigzag Chain ◽  
Uranyl Ions ◽  
Oxide Hydrate ◽  
Single Sheet

AbstractThe uranyl oxide hydrates (UOH) are important corrosion products of uraninite and UO 2 in spent nuclear fuel under oxidizing conditions. However, the systematics of the crystal chemistry, thermodynamic parameters, and solubilities of this mineral group are poorly understood. With the exception of the synthetic UO2 (OH)2 polymorphs, all UOH crystal structures are based on sheets of edge-sharing 5- and 4-coordinated uranyl dipyramids. This structural similarity suggests that it is possible to develop a model by which to estimate the thermodynamic behavior of UOHs from data on structural endmember phases. Toward this end, a method of quantitatively describing all known UOH sheets has been developed. Only four structural unit chains are required to construct the uranyl oxide hydrate sheets (as well as the structurally similar U3O8 sheets). The H-chain is restricted to α-UO2 (OH)2 and is made up of hexagonally coordinated uranyl ions sharing opposing edges. The “arrowhead” chain composed of pentagonal dipyramids sharing edges and alternating with trigonal vacancies is present in all other UOH sheets. These arrowhead chains are directed and can occur in both an ↑ and ⇓ “sense” within a single sheet. The P-chain consists of edge-sharing pentagonal dipyramids forming a zigzag chain. The P-chain is flanked on both sides by arrowhead chains of the same “sense”. The remaining structural unit is a discontinuous “chain” of rhombic dipyramids. This “R-chain” is produced when nested adjacent ⇑ and ⇓arrowhead chains are translated by a diagonal shift. This “chain” occurs in sheets which contain only 4-coordinate uranyl ion and those containing both 4- and 5-coordinate uranyl ions.

scholarly journals The crystal structure of szenicsite, Cu3MoO4(OH)4

1998 ◽  
Vol 62 (04) ◽  
pp. 461-469 ◽  
Author(s):  
Peter C. Burns
Keyword(s):  
Crystal Structure ◽  
Goodness Of Fit ◽  
Direct Methods ◽  
Ligand Field ◽  
Area Detector ◽  
Vertex Sharing ◽  
Distorted Octahedral ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Least Squares Techniques

Abstract The crystal structure of szenicsite, Cu3MoO4(OH)4, orthorhombic, a = 8.5201(8), b = 12.545(1), c = 6.0794(6) Å, V = 649.8(2) Å3, space group Pnnm, Z = 4, has been solved by direct methods and refined by least-squares techniques to an agreement index (R) of 3.34% and a goodness-of-fit (S) of 1.11 for 686 unique observed [|F| ⩾ 4σF] reflections collected using graphite-monochromated Mo-Kα X-radiation and a CCD area detector. The structure contains three unique Cu2+ positions that are each coordinated by six anions in distorted octahedral arrangements; the distortions of the octahedra are due to the Jahn-Teller effect associated with a d 9 metal in an octahedral ligand-field. The single unique Mo6+ position is tetrahedrally coordinated by four O2− anions. The Cu2+ϕ6 (ϕ: unspecified ligand) octahedra share trans edges to form rutile-like chains, three of which join by the sharing of octahedral edges to form triple chains that are parallel to [001]. The MoO4 tetrahedra are linked to either side of the triple chain of Cu2+ϕ6 octahedra by the sharing of two vertices per tetrahedron, and the resulting chains are cross-linked through tetrahedral-octahedral vertex sharing to form a framework structure. The structure of szenicsite is closely related to that of antlerite, Cu3SO4(OH)4, which contains similar triple chains of edge-sharing Cu2+ϕ6 octahedra.

The crystal structure of gatehouseite

2011 ◽  
Vol 75 (6) ◽  
pp. 2823-2832
Author(s):  
P. Elliott ◽  
A. Pring
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Direct Methods ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Manganese Phosphate ◽  
Phosphate Mineral ◽  
Unit Formula

AbstractThe crystal structure of the manganese phosphate mineral gatehouseite, ideally Mn52+(PO4)2(OH)4, space group P212121, a = 17.9733(18), b = 5.6916(11), c = 9.130(4) Å, V= 933.9(4) Å3, Z = 4, has been solved by direct methods and refined from single-crystal X-ray diffraction data (T = 293 K) to an R index of 3.76%. Gatehouseite is isostructural with arsenoclasite and with synthetic Mn52+(PO4)2(OH)4. The structure contains five octahedrally coordinated Mn sites, occupied by Mn plus very minor Mg with observed <Mn—O> distances from 2.163 to 2.239 Å. Two tetrahedrally coordinated P sites, occupied by P, Si and As, have <P—O> distances of 1.559 and 1.558 Å. The structure comprises two types of building unit. A strip of edge-sharing Mn(O,OH)6 octahedra, alternately one and two octahedra wide, extends along [010]. Chains of edge- and corner-shared Mn(O,OH)6 octahedra coupled by PO4 tetrahedra extend along [010]. By sharing octahedron and tetrahedron corners, these two units form a dense three-dimensional framework, which is further strengthened by weak hydrogen bonding. Chemical analyses by electron microprobe gave a unit formula of (Mn4.99Mg0.02)Σ5.01(P1.76Si0.07(As0.07)Σ2.03O8(OH)3.97.

scholarly journals Poly[bis(μ-4-aminobenzenesulfonato-κ2 N:O)diaquacobalt(II)]

IUCrData ◽  
2018 ◽  
Vol 3 (8) ◽  
Author(s):  
Antoine Blaise Kama ◽  
Mamadou Sidibe ◽  
Cheikh Abdoul Khadre Diop ◽  
Florent Blanchard
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Title Compound ◽  
Three Dimensional ◽  
Water Molecules ◽  
Supramolecular Framework ◽  
Distorted Octahedral Environment ◽  
Octahedral Environment ◽  
Distorted Octahedral

The title compound, [Co(C6H6NO3S)2(H2O)2] n , was obtained from a mixture of Co(NO3)2·6H2O and a previously synthesized salt, namely CyNH3·NH2PhSO3, in a 1:1 ratio (Cy = cyclohexyl; Ph = phenyl). The crystal structure consists of a three-dimensional supramolecular framework, in which polymeric layers are interconnected via N—H...O and O—H...O hydrogen bonding. The polymeric layers are formed by an interconnection of neighbouring cobalt(II) cations via NH2PhSO3 − bridges. Each cobalt(II) cation is surrounded by four NH2PhSO3 − moieties and two water molecules, leading to a distorted octahedral environment.

Synthesis and characterization of a uranium oxide hydrate framework with Sr(II) ions: Structural insights and mixed uranium valences

2022 ◽  
Author(s):  
Kim Lu ◽  
Yingjie Zhang ◽  
Tao Wei ◽  
Timothy Ablott ◽  
Thanh Ha Nguyen ◽  
...  
Keyword(s):  
Uranium Oxide ◽  
Mixed Valence ◽  
Synthesis And Characterization ◽  
Monoclinic Space Group ◽  
Spectroscopic Techniques ◽  
Space Group ◽  
Oxide Hydrate ◽  
Structural Insights

A mixed-valence uranium oxide hydrate framework with Sr2+ ions (UOF-Sr2) was synthesized hydrothermally and characterized with multiple structural and spectroscopic techniques. Compound UOF-Sr2 crystallizes in monoclinic space group C2/c, having...

Redetermination of trans-diaquabis(picolinato-κ2 N,O)cobalt(II) dihydrate

2006 ◽  
Vol 62 (4) ◽  
pp. m796-m798 ◽  
Author(s):  
Zerrin Heren ◽  
Cem Cüneyt Ersanlı ◽  
Cem Keser ◽  
Nazan Ocak Ískeleli
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Title Compound ◽  
Three Dimensional ◽  
Water Molecules ◽  
Inversion Center ◽  
Hydrogen Bonding Interactions ◽  
Dimensional Network ◽  
Distorted Octahedral

The crystal structure of the title compound, [Co(C6H4NO2)2(H2O)2]·2H2O, has been reinvestigated with improved precision [previous reports: Chang et al. (1972). J. Coord. Chem. 2, 31–34; Lumme et al. (1969). Suom. Kemistil. B, 42, 270]. In the title compound, the Co atom is located on an inversion center and its coordination can be described as slightly distorted octahedral, equatorially trans-coordinated by two N and O atoms of two picolinate ligands and axially coordinated by two O atoms of the water molecules. Intermolecular O—H...O and C—H...O hydrogen-bonding interactions result in the formation of an intricate three-dimensional network.

scholarly journals Crystal structure of tetraaqua(5,5′-dimethyl-2,2′-bipyridyl-κ2N,N′)iron(II) sulfate

2014 ◽  
Vol 70 (12) ◽  
pp. 544-546 ◽  
Author(s):  
Yamine Belamri ◽  
Fatima Setifi ◽  
Bojana M. Francuski ◽  
Sladjana B. Novaković ◽  
Setifi Zouaoui
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Coordination Bond ◽  
Octahedral Geometry ◽  
The Other ◽  
Distorted Octahedral Geometry ◽  
Cationic Complex ◽  
Centroid Distance ◽  
Distorted Octahedral ◽  
Coordination Bonds

In the title compound, [Fe(C12H12N2)(H2O)4]SO4, the central FeIIion is coordinated by two N atoms from the 5,5′-dimethyl-2,2′-bipyridine ligand and four water O atoms in a distorted octahedral geometry. The Fe—O coordination bond lengths vary from 2.080 (3) to 2.110 (3) Å, while the two Fe—N coordination bonds have practically identical lengths [2.175 (3) and 2.177 (3) Å]. The chelating N—Fe—N angle of 75.6 (1)° shows the largest deviation from an ideal octahedral geometry; the other coordination angles deviate from ideal values by 0.1 (1) to 9.1 (1)°. O—H...O hydrogen bonding between the four aqua ligands of the cationic complex and four O-atom acceptors of the anion leads to the formation of layers parallel to theabplane. Neighbouring layers further interact by means of C—H...O and π–π interactions involving the laterally positioned bipyridine rings. The perpendicular distance between π–π interacting rings is 3.365 (2) Å, with a centroid–centroid distance of 3.702 (3) Å.

scholarly journals Crystal structure of bis(acetylacetonato-κ2O,O′)(tetrahydrofuran-κO)(trifluoromethanesulfonato-κO)iron(III)

2015 ◽  
Vol 71 (10) ◽  
pp. 1165-1168
Author(s):  
Casseday P. Richers ◽  
Jeffery A. Bertke ◽  
Thomas B. Rauchfuss
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Site Occupancy ◽  
Title Complex ◽  
Two Dimensional ◽  
Hydrogen Bonding Interactions ◽  
Octahedral Environment ◽  
Distorted Octahedral ◽  
Length Range ◽  
A Site

The mononuclear title complex, [Fe(CF3O3S)(C5H7O2)2(C4H8O)] or [Fe(acac)2(OTf)(THF)] (acac = acetylacetonate; OTf = trifluoromethanesulfonate; THF = tetrahydrofuran), (I), consists of one six-coordinate Fe3+atom in a slightly distorted octahedral environment [Fe—O bond-length range = 1.9517 (11)–2.0781 (11) Å]. The triflate ligand was found to be disordered over two sets of sites, with a site-occupancy ratio of 0.622 (16):0.378 (16). Weak intermolecular C—H...O and C—H...F hydrogen-bonding interactions generate a two-dimensional supramolecular structure lying parallel to (100). This is only the second crystal structure reported of a mononuclear bis(acetylacetonato)iron(III) complex.

A heterotrimetallic Ni(II)–Dy(III) bis(salamo)-based complex: synthesis, structure and fluorescent property

2018 ◽  
Vol 73 (5) ◽  
pp. 281-288
Author(s):  
Qing Zhao ◽  
Ying-Qi Pan ◽  
Xiao-Yan Li ◽  
Han Zhang ◽  
Wen-Kui Dong
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Supramolecular Structure ◽  
Fluorescence Spectra ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray ◽  
Distorted Octahedral ◽  
Tricapped Trigonal Prism ◽  
Elemental Analyses

AbstractA discrete heterotrinuclear complex [{Ni2LDy(OAc)3(CH3OH)}2] · 2CH3OH · 3CH2Cl2, with a naphthalenediol-based acyclic bis(salamo) ligand H4L, has been synthesized and structurally characterized using elemental analyses, IR, UV/Vis and fluorescence spectra and single crystal X-ray diffraction. The crystal structure shows two crystallographically independent but chemically identical molecules (molecules I and II). All the Ni(II) atoms are hexa-coordinated with slightly distorted octahedral geometries. The central Dy atoms are nona-coordinated with slightly distorted tricapped trigonal prism geometries. An infinite 3D supramolecular structure is formed via intermolecular hydrogen bonding and C–H…π interactions.

scholarly journals Crystal structure offac-trichlorido[tris(pyridin-2-yl-N)amine]chromium(III)

2015 ◽  
Vol 71 (1) ◽  
pp. 73-75 ◽  
Author(s):  
Yukiko Yamaguchi-Terasaki ◽  
Takashi Fujihara ◽  
Akira Nagasawa ◽  
Sumio Kaizaki
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Complex Molecule ◽  
Three Dimensional ◽  
Mirror Plane ◽  
Neutral Complex ◽  
Distorted Octahedral Coordination ◽  
Hydrogen Bonding Interactions ◽  
Dimensional Network ◽  
Distorted Octahedral

In the neutral complex molecule of the title compound,fac-[CrCl3(tpa)] [tpa is tris(pyridin-2-yl)amine; C15H12N4], the CrIIIion is bonded to three N atoms that are constrained to afacialarrangement by the tpa ligand and by three chloride ligands, leading to a distorted octahedral coordination sphere. The average Cr—N and Cr—Cl bond lengths are 2.086 (5) and 2.296 (4) Å, respectively. The complex molecule is located on a mirror plane. In the crystal, a combination of C—H...N and C—H...Cl hydrogen-bonding interactions connect the molecules into a three-dimensional network.

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