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Uroxite (IMA2018-100), [(UO2)2(C2O4)(OH)2(H2O)2]·H2O, and metauroxite (2019-030), (UO2)2(C2O4)(OH)2(H2O)2, are the first two uranyl-oxalate minerals. Uroxite was found in the Markey mine, Red Canyon, Utah, USA and in the Burro mine, Slick Rock district, Colorado, USA. Metauroxite was found only in the Burro mine. Both minerals are post-mining, secondary phases found in efflorescent crusts on mine walls. Uroxite occurs as light yellow, striated blades exhibiting moderate neon-green fluorescence, ca 2 Mohs hardness, good {101} and {010} cleavages, density(calc) = 4.187 g/cm3; optics: biaxial (–), α = 1.602(2), β = 1.660(2), γ = 1.680(2) (white light), 2Vmeas. = 59(1)°, moderate r > v dispersion, orientation Y = b, Z ^ a = 35° in obtuse β, nonpleochroic. Metauroxite occurs as light yellow crude blades and tablets exhibiting weak green-gray fluorescence, ca 2 Mohs hardness, good {001}cleavage, densitycalc = 4.403 g/cm3; approximate optics: α′ = 1.615(5), γ′ = 1.685(5). Electron probe microanalysis provided UO3 79.60, C2O3 10.02, H2O 10.03, total 99.65 wt.% for uroxite and UO3 82.66, C2O3 10.40, H2O 7.81, total 100.87 wt.% for metauroxite; C2O3 and H2O based on the structures. Uroxite is monoclinic, P21/c, a = 5.5698(2), b = 15.2877(6), c = 13.3724(9) Å, β = 94.015(7)°, V = 1135.86(10) Å3 and Z = 4. Metauroxite is triclinic, P–1, a = 5.5635(3), b = 6.1152(4), c = 7.8283(4) Å, α = 85.572(5), β = 89.340(4), γ = 82.468°, V = 263.25(3) Å3 and Z = 1. In the structure of uroxite (R1 = 0.0333 for 2081 I > 2I reflections), UO7 pentagonal bipyramids share corners forming [U4O24] tetramers, which are linked by C2O4 groups to form corrugated sheets. In the structure of metauroxite (R1 = 0.0648 for 1602 I > 2I reflections) UO7 pentagonal bipyramids share edges forming [U2O12] dimers, which are linked by C2O4 groups to form zig-zag chains.

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... Nitroplumbite was found underground at the Burro mine, Slick Rock district, San Miguel County, Colorado, USA (38.04507N, 108.88972W). This is also the type locality for several other species, including ammoniolasalite (Kampf et al. 2018a), ammoniomathesiusite (Kampf et al. 2019), ammoniozippeite (Kampf et al. 2018b), bobfinchite (Olds et al. 2021), burroite (Kampf et al. 2017b), caseyite (Kampf et al. 2020a), metamunirite (Evans, 1991), metauroxite (Kampf et al. 2020b), okieite (Kampf et al. 2020c), protocaseyite (Kampf et al. 2022), and uroxite (Kampf et al. 2020b). The Burro mine is near the southern end of the Uravan mineral belt, in an area where uranium and vanadium minerals occur together in bedded or roll-front deposits in the sandstone of the Salt Wash member of the Jurassic Morrison Formation (Carter & Gualtieri 1965, Shawe 2011. ...
... Nitroplumbite was found underground at the Burro mine, Slick Rock district, San Miguel County, Colorado, USA (38.04507N, 108.88972W). This is also the type locality for several other species, including ammoniolasalite (Kampf et al. 2018a), ammoniomathesiusite (Kampf et al. 2019), ammoniozippeite (Kampf et al. 2018b), bobfinchite (Olds et al. 2021), burroite (Kampf et al. 2017b), caseyite (Kampf et al. 2020a), metamunirite (Evans, 1991), metauroxite (Kampf et al. 2020b), okieite (Kampf et al. 2020c), protocaseyite (Kampf et al. 2022), and uroxite (Kampf et al. 2020b). The Burro mine is near the southern end of the Uravan mineral belt, in an area where uranium and vanadium minerals occur together in bedded or roll-front deposits in the sandstone of the Salt Wash member of the Jurassic Morrison Formation (Carter & Gualtieri 1965, Shawe 2011. ...
Article
Nitroplumbite (IMA2021-045a), [Pb4(OH)4](NO3)4, is a new mineral discovered at the Burro mine, Slick Rock district, San Miguel County, Colorado, USA. It occurs in a secondary efflorescent assemblage on asphaltite and montroseite- and corvusite-bearing sandstone in association with baryte, chalcomenite, and volborthite. The mineral forms as brown equant (pseudocubic) or colorless bladed crystals. The streak is white, luster is vitreous to greasy, Mohs hardness is 2½, tenacity is brittle, and fracture is conchoidal. Nitroplumbite is optically biaxial (–) with α = 1.790(5), β =1.820 (est.), and γ = 1.823 (est.) (white light); 2Vmeas = 35(1)°; optical orientation: Z = b; nonpleochroic. The calculated density is 5.297 g/cm3 for the empirical formula. Electron probe microanalysis provided the empirical formula Pb4.18(OH)4(N0.98O3)4. Nitroplumbite is monoclinic, space group Ia, a = 18.3471(7), b = 17.3057(4), c = 18.6698(8) Å, β = 91.872(3)°, V = 5924.7(4) Å3, and Z = 16. The crystal structure (R1 = 0.0509 for 11161 I > 2σI reflections) is the same as that previously determined for its synthetic analogue. It consists of isolated, internally bonded cubane-like [Pb4(OH)4]4+ clusters and isolated (NO3)– groups that are linked together by long Pb–O bonds and hydrogen bonds.
... Protocaseyite was found underground at the Burro mine, Slick Rock district,San Miguel County,Colorado,U.S.A. (38.04507,. The Burro mine is the type locality for ammoniolasalite (Kampf et al. 2018a); ammoniomatesiusite (Kampf et al. 2019b); ammoniozippeite (Kampf et al. 2018b); burroite (Kampf et al. 2017b); caseyite (Kampf et al. 2020a); metamunirite (Evans 1991); metauroxite (Kampf et al. 2020b); okieite (Kampf et al. 2020c); and uroxite (Kampf et al. 2020b). The mine is near the southern end of the Uravan mineral belt in which uranium and vanadium minerals occur together in bedded or roll-front deposits in the sandstone of the Salt Wash member of the Jurassic Morrison Formation (Carter and Gualtieri 1965;Shawe 2011). ...
... Protocaseyite was found underground at the Burro mine, Slick Rock district,San Miguel County,Colorado,U.S.A. (38.04507,. The Burro mine is the type locality for ammoniolasalite (Kampf et al. 2018a); ammoniomatesiusite (Kampf et al. 2019b); ammoniozippeite (Kampf et al. 2018b); burroite (Kampf et al. 2017b); caseyite (Kampf et al. 2020a); metamunirite (Evans 1991); metauroxite (Kampf et al. 2020b); okieite (Kampf et al. 2020c); and uroxite (Kampf et al. 2020b). The mine is near the southern end of the Uravan mineral belt in which uranium and vanadium minerals occur together in bedded or roll-front deposits in the sandstone of the Salt Wash member of the Jurassic Morrison Formation (Carter and Gualtieri 1965;Shawe 2011). ...
Article
Protocaseyite, [Al4(OH)6(H2O)12][V10O28]·8H2O, is a new mineral (IMA 2020-090) occurring in low-temperature, post-mining, secondary mineral assemblages at the Burro mine, Slick Rock district, San Miguel County, Colorado, USA. Crystals of protocaseyite are saffron-yellow, thick blades, with pale orange-yellow streak, vitreous luster, brittle tenacity, curved fracture, two very good cleavages, a Mohs hardness of 2, and a density of 2.45(2) g/cm3. The optical properties of protocaseyite could be only partly determined: biaxial with α = 1.755(5), β < 1.80, γ > 1.80 (white light); pleochroic with X and Y yellow, Z orange (X ≈ Y < Z). Electron-probe microanalysis and crystal-structure solution and refinement provided the empirical formula [(Al3.89Mg0.11Ca0.02)Σ4.02(OH)6(H2O)12][H0.06V10O28]·8H2O. Protocaseyite is triclinic, P-1, a = 9.435(2), b = 10.742(3), c = 11.205(3) Å, α = 75.395(7), β = 71.057(10), γ = 81.286(6)°, V = 1036.4 (5) Å3, and Z = 1. The crystal structure (R1 = 0.026 for 4032 Io > 2sig(I) reflections) contains both the [V10O28]6- decavanadate polyoxoanion and a novel [Al4(OH)6(H2O)12]6+ polyoxocation.
... It occurs on gypsum-coated asphaltum in association with andersonite, calcite, gypsum and natromarkeyite (Kampf et al., 2020a). Other new minerals recently described from the Markey mine are feynmanite (Kampf et al., 2019a), leószilárdite (Olds et al., 2017), magnesioleydetite (Kampf et al., 2019b), markeyite (Kampf et al., 2018), meyrowitzite (Kampf et al., 2019c), pseudomarkeyite (Kampf et al., 2020a), straβmannite (Kampf et al., 2019b) and uroxite (Kampf et al., 2020b). ...
Article
The new mineral paramarkeyite (IMA2020–024), Ca2(UO2)(CO3)3·5H2O, was found in the Markey mine, San Juan County, Utah, USA, where it occurs as a secondary phase on gypsum-coated asphaltum in association with andersonite, calcite, gypsum and natromarkeyite. Paramarkeyite crystals are transparent, pale green-yellow, striated tablets, up to 0.11 mm across. The mineral has white streak and vitreous lustre. It exhibits moderate bluish white fluorescence (405 nm laser). It is very brittle with irregular, curved fracture and a Mohs hardness of 2½. It has an excellent {100} cleavage and probably two good cleavages on {010} and {001}. The measured density is 2.91(2) g cm–3. Optically, the mineral is biaxial (–) with α = 1.550(2), β = 1.556(2), γ = 1.558(2) (white light); 2V = 60(2)°; strong r > v dispersion; orientation: Y = b; nonpleochroic. The Raman spectrum exhibits bands consistent with UO22+, CO32– and O–H. Electron microprobe analysis provided the empirical formula (Ca1.83Na0.20Sr0.03)∑2.05(UO2)(CO3)3·5H2O (+0.07 H). Paramarkeyite is monoclinic, P21/n, a = 17.9507(7), b = 18.1030(8), c = 18.3688(13) Å, β = 108.029(8)°, V = 5676.1(6) Å3 and Z = 16. The structure of paramarkeyite (R1 = 0.0647 for 6657 I > 2I) contains uranyl tricarbonate clusters that are linked by Ca–O polyhedra to form heteropolyhedral layers. The structure of paramarkeyite is very similar to those of markeyite, natromarkeyite and pseudomarkeyite.
Article
Uranyl ion, UO 2 ²⁺ , and its aqueous complexes with organic and inorganic ligands can be the dominant species for uranium transport on the Earth surface or in a nuclear waste disposal system if an oxidizing condition is present. As an important biodegradation product, oxalate, C 2 O 4 ²⁻ , is ubiquitous in natural environments and is known for its ability to complex with the uranyl ion. Oxalate can also form solid phases with uranyl ion in certain environments thus limiting uranium migration. Therefore, the determination of stability constants for aqueous and solid uranyl oxalate complexes is important not only to the understanding of uranium mobility in natural environments, but also to the performance assessment of nuclear waste disposal. Here we developed a thermodynamic model for the UO 2 ²⁺ –Na ⁺ –H ⁺ –Cl – –ClO 4 – –C 2 O 4 2– –NO 3 – –H 2 O system to ionic strength up to ∼11 mol•kg ⁻¹ . We constrained the stability constants for UO 2 C 2 O 4 (aq) and UO 2 (C 2 O 4 ) 2 ²⁻ at infinite dilution based on our evaluation of the literature data over a wide range of ionic strengths up to ∼11 mol•kg ⁻¹ . We also obtained the solubility constants at infinite dilution for solid uranyl oxalates, UO 2 C 2 O 4 •3H 2 O, based on the solubility data over a wide range of ionic strengths. The developed model will enable for the accurate stability assessment of oxalate complexes affecting uranium mobility under a wide range of conditions including those in deep geological repositories.
Article
The new minerals natromarkeyite, Na 2 Ca 8 (UO 2) 4 (CO 3) 13 (H 2 O) 24 ⋅3H 2 O (IMA2018-152) and pseudomarkeyite, Ca 8 (UO 2) 4 (CO 3) 12 (H 2 O) 18 ⋅3H 2 O (IMA2018-114) were found in the Markey mine, San Juan County, Utah, USA, where they occur as secondary phases on asphaltum. Natromarkeyite properties are: untwinned blades and tablets to 0.2 mm, pale yellow green colour; transparent; white streak; bright bluish white fluorescence (405 nm laser); vitreous to pearly lustre; brittle; Mohs hardness 1½ to 2; irregular fracture; three cleavages ({001} perfect, {100} and {010} good); density = 2.70(2) g cm-3 ; biaxial (-) with α = 1.528(2), β = 1.532(2) and γ = 1.533(2); and pleochroism is X = pale green yellow, Y ≈ Z = light green yellow. Pseudomarkeyite properties are: twinned tapering blades and tablets to 1 mm; pale green yellow colour; transparent; white streak; bright bluish white fluorescence (405 nm laser); vitreous to pearly lustre; brittle; Mohs hardness ≈ 1; stepped fracture; three cleavages ({10 1} very easy, {010} good, {100} fair); density = 2.88(2) g cm-3 ; biaxial (-) with α = 1.549(2), β = 1.553(2) and γ = 1.557(2); and it is nonpleochroic. The Raman spectra of markeyite, natromar-keyite and pseudomarkeyite are very similar and exhibit bands consistent with UO 2 2+ , CO 3 2-and O-H. Electron microprobe analyses provided the empirical formula Na 2.01 Ca 7.97 Mg 0.03 Cu 2+ 0.05 (UO 2) 4 (CO 3) 13 (H 2 O) 24 ⋅3H 2 O (-0.11 H) for natromarkeyite and Ca 7.95 (UO 2) 4 (CO 3) 12 (H 2 O) 18 ⋅3H 2 O (+0.10 H) for pseudomarkeyite. Natromarkeyite is orthorhombic, Pmmn, a = 17.8820(13), b = 18.3030(4), c = 10.2249(3) Å, V = 3336.6(3) Å 3 and Z = 2. Pseudomarkeyite is monoclinic, P2 1 /m, a = 17.531(3), b = 18.555(3), c = 9.130(3) Å, β = 103.95(3)°, V = 2882.3(13) Å 3 and Z = 2. The structures of natromarkeyite (R 1 = 0.0202 for 2898 I > 2σI) and pseudomarkeyite (R 1 = 0.0787 for 2106 I > 2σI) contain uranyl tricarbonate clusters that are linked by (Ca/Na)-O polyhedra forming thick corrugated heteropolyhedral layers. Natromarkeyite is isostructural with markeyite; pseudomarkeyite has a very similar structure.
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The new minerals natromarkeyite (IMA2018-152), Na 2 Ca 8 (UO 2) 4 (CO 3) 13 (H 2 O) 24 ·3H 2 O, and pseudomarkeyite (IMA2018-114), Ca 8 (UO 2) 4 (CO 3) 12 (H 2 O) 18 ·3H 2 O, were found in the Markey mine, San Juan County, Utah, USA, where they occur as secondary phases on asphaltum. Natromarkeyite properties: untwinned blades and tablets to 0.2 mm, pale yellow-green colour; transparent; white streak; 2 bright bluish white fluorescence (405 nm laser); vitreous to pearly lustre; brittle; Mohs hardness 1½ to 2; irregular fracture; three cleavages ({001} perfect, {100} and {010} good); 2.70(2) g cm-3 density; biaxial (-) with α = 1.528(2), β = 1.532(2), γ = 1.533(2); pleochroism: X pale green yellow, Y ≈ Z light green yellow. Pseudomarkeyite properties: twinned tapering blades and tablets to 1 mm; pale green-yellow colour; transparent; white streak; bright bluish white fluorescence (405 nm laser); vitreous to pearly lustre; brittle; Mohs hardness ~1; stepped fracture; three cleavages ({10-1} very easy, {010} good, {100} fair); 2.88(2) g cm-3 density; biaxial (-) with α = 1.549(2), β = 1.553(2), γ = 1.557(2); nonpleochroic. The Raman spectra of markeyite, natromarkeyite and pseudomarkeyite are very similar and exhibit bands consistent with UO 2 2+ , CO 3 2-and O-H. Electron microprobe analyses provided the empirical formula Na 2.01 Ca 7.97 Mg 0.03 Cu 2+ 0.05 (UO 2) 4 (CO 3) 13 (H 2 O) 24 ·3H 2 O (-0.11 H) for natromarkeyite and Ca 7.95 (UO 2) 4 (CO 3) 12 (H 2 O) 18 ·3H 2 O (+0.10 H) for pseudomarkeyite. Natromarkeyite is orthorhombic, Pmmn, a = 17.8820(13), b = 18.3030(4), c = 10.2249(3) Å, V = 3336.6(3) Å^3 and Z = 2. Pseudomarkeyite is monoclinic, P2 1 /m, a = 17.531(3), b = 18.555(3), c = 9.130(3) Å, β = 103.95(3)°, V = 2882.3(13) Å^3 and Z = 2. The structures of natromarkeyite (R1 = 0.0202 for 2898 I > 2sigmaI) and pseudomarkeyite (R1 = 0.0787 for 2106 I > 2sigmaI) contain uranyl tricarbonate clusters that are linked by (Ca/Na)-O polyhedra forming thick corrugated heteropolyhedral layers. Natromarkeyite is isostructural with markeyite; pseudomarkeyite has a very similar structure.
Article
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The geometry, bond valences, and polymerization of hexavalent uranium polyhedra from 105 well-refined structures are analyzed. The U6+ cation is almost always present in crystal structures as part of a nearly linear (UO2)(2+) uranyl ion that is coordinated by four, five or six equatorial anions in an approximately planar arrangement perpendicular to the uranyl ion, giving square, pentagonal and hexagonal bipyramids, respectively. The U6+-O-Ur bond length (O-Ur: uranyl-ion O atom) is independent of the equatorial anions of the polyhedra; averages of all polyhedra that contain uranyl ions are: U-[6](6+)-O-Ur = 1.79(3), (7)U6+-O-Ur = 1.79(4), and [8]U6+-O-Ur = 1.78(3) Angstrom. Not all U-[6](6+) polyhedra contain uranyl ions; there is a continuous series of coordination polyhedra, from square bipyramidal polyhedra with uranyl ions to holosymmetric octahedral geometry. The U-[7](6+) and U-[8](6+) Polyhedra invariably contain a uranyl ion. The equatorial U6+-phi (phi: O2-, OH-) bond-lengths of uranyl polyhedra depend upon coordination number: averages for all polyhedra are U-[6](6+)-phi(eq) = 2.28(5), U-[7](6+)-phi(eq) = 2.37(9), and U-[8](6+)-phi(eq) = 2.47(12) Angstrom. Currently available bond-valence parameters for U6+ are unsatisfactory for determining bond-valence sums. Coordination-specific bond-valence parameters have been derived for U6+, together with parameters applicable to all coordination geometries. The parameters give bond-valence sums for U6+ of similar to 6 VII and reasonable bond-valences for U6+-O-Ur bonds. The bond-valence parameters facilitate the recognition of U4+, U5+ and U6+ cations in refined crystal structures. The crystal-chemical constraints of polyhedral polymerization in uranyl phases are discussed.
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New minerals and nomenclature modifications approved in 2019 - Volume 83 Issue 4 - Ritsuro Miyawaki, Frédéric Hatert, Marco Pasero, Stuart J. Mills
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In this study, the structural properties, main characteristics of the Raman spectrum, and the thermodynamic properties of the ammonium oxalate monohydrate mineral oxammite, were investigated in theoretical solid-state calculations based on the periodic density functional theory using plane waves and pseudopotentials. The optimized structure of oxammite agreed very well with that obtained from low temperature X-ray diffraction data by structure refinement (orthorhombic symmetry, space group P21 21 2; lattice parameters: = 8.017 Å; = 10.309 Å; = 3.735 Å). The calculated structural properties, including the lattice parameters, bond lengths and angles, and X-ray powder pattern, accurately reproduced the experimental information. The Raman spectrum determined theoretically agreed with that obtained experimentally. The assignment of the Raman spectral bands significantly improved their previous empirical assignment. Thus, the assignment of a large series of bands was modified and the origins of several previously unassigned bands were found. Five bands in the experimental spectrum at 2344, 2161, 1933, 1902, and 815 cm-1, were absent from the computed spectrum and they were identified as combination bands. The band located at 2879 cm-1 was confirmed as an overtone. Furthermore, the theoretical calculations clearly showed that some features described as single peaks in previous experimental studies were due to the contributions of several bands. The thermodynamic properties of the oxammite mineral, including the specific heats, entropies, enthalpies, and Gibbs free energies, were determined as functions of temperature. The specific heat calculated at 323 K, Cp= 202.3 J K-1mol-1, was in good agreement with the corresponding experimental heat capacity, = 211.7 J K-1 mol-1, where the values only differed by about 4%. Finally, using the computed thermodynamic data, the thermodynamic properties of the formation of oxammite as well as the free energies and reaction constants of the reaction for its thermal decomposition were determined.
Article
The new minerals klaprothite (IMA2015-087), Na6(UO2)(SO4)4(H2O)4, péligotite (IMA2015-088), Na6(UO2)(SO4)4(H2O)4, and ottohahnite (IMA2015-098), Na6(UO2)2(SO4)5(H2O)7·1.5H2O, were found in the Blue Lizard mine, San Juan County, Utah, USA, where they occur together as secondary phases. All three minerals occur as yellowish green to greenish-yellow crystals, are brittle with irregular fracture, have Mohs hardness of about 2½ and exhibit bright bluish-green fluorescence, and all are easily soluble in RT H2O. Only klaprothite exhibits cleavage; perfect on {100} and {001}. Quantitative EDS analyses yielded the empirical formulas Na6.01(U 26 1.03O2)(S0.993O4)4(H2O)4, Na5.82(U1.02O2)(S1.003O4)4(H2O)4 and Na5.88(U0.99O2)2(S1.008O4)5(H2O)8.5 for klaprothite, péligotite and ottohahnite, respectively. Their Raman spectra exhibit similar features. Klaprothite is monoclinic, P21/c, a = 9.8271(4), b = 9.7452(3), c = 20.8725(15) Å, β =98.743(7)°, V = 1975.66(17) Å3 and Z = 4. Péligotite is triclinic, P-1, a = 9.81511(18), b =9.9575(2), c = 10.6289(8) Å, α = 88.680(6)°, β = 73.990(5)°, γ = 89.205(6)°, V = 998.22(8) Å3 and Z = 2. Ottohahnite is triclinic, P-1, a = 9.97562(19), b = 11.6741(2), c = 14.2903(10) Å, α = 113.518(8)°, β = 104.282(7)°, γ = 91.400(6)°, V = 1464.59(14) Å3 and Z = 2. The structures of klaprothite (R1 = 2.22%) and péligotite (R1 = 2.28%) both contain [(UO2)(SO4)4]6– clusters in which one SO4 group has a bidentate linkage with the UO7 polyhedron; Na–O polyhedra link clusters into thick heteropolyhedral layers and link layers into frameworks; the structures differ in the configuration of Na-O polyhedra that link the layers. The structure of ottohahnite (R1 = 2.65%) contains [(UO2)4(SO4)10]12– clusters in which each UO7 polyhedron has a bidentate linkage with one SO4 group; Na–O polyhedra link clusters into a thin heteropolyhedral slice and also link the slices into a framework. The minerals are named for Martin Heinrich Klaproth (1743–1817), Eugène-Melchior Péligot (1811–1890) and Otto Hahn (1879–1968).
Article
A laboratory project for the upper-division physical chemistry laboratory is described, and it combines IR and Raman spectroscopies with Gaussian electronic structure calculations to determine the structure of the oxalate anion in solid alkali oxalates and in aqueous solution. The oxalate anion has two limiting structures whose vibrational spectra have distinct differences: planar with D2h symmetry and nonplanar with D2d symmetry. In the former case, the IR and Raman spectra are complementary. Students measure the IR and Raman spectra of solid Na2C2O4, K2C2O4, and Cs2C2O4, and a nearly saturated aqueous solution of K2C2O4. They also carry out Gaussian calculations on the oxalate anion to predict the vibrational wavenumbers of both the planar and nonplanar structures and use the results to assign the spectra. By considering their results for the four samples, they decide on the oxalate structure in each and defend their choice in a report. The complexity of the project immerses the students in vibrational spectroscopy so that they learn the subject at a deeper level. © 2016 The American Chemical Society and Division of Chemical Education, Inc.
Article
The reliability of the compatability index as a measure of the compatability of mean index of refraction, density and chemical composition was tested on sets of published data for organic compounds, and inorganic compounds, particularly minerals. Calculations based on these data sets were used to prepare a revised set of Gladstone-Dale constants. Application of the compatability index to other sets of data (garnets, axinities, scapolites and new minerals) allows assessment of the data and commonly points to errors.-M.I.C.
Book
This book describes the bond valence model, a description of acid-base bonding which is becoming increasingly popular particularly in fields such as materials science and mineralogy where solid state inorganic chemistry is important. Recent improvements in crystal structure determination have allowed the model to become more quantitative. Unlike other models of inorganic chemical bonding, the bond valence model is simple, intuitive, and predictive, and can be used for analysing crystal structures and the conceptual modelling of local as well as extended structures. This is the first book to explore in depth the theoretical basis of the model and to show how it can be applied to synthetic and solution chemistry. It emphasizes the separate roles of the constraints of chemistry and of three-dimensional space by analysing the chemistry of solids. Many applications of the model in physics, materials science, chemistry, mineralogy, soil science, surface science, and molecular biology are reviewed. The final chapter describes how the bond valence model relates to and represents a simplification of other models of inorganic chemical bonding.
Chapter
For about 20 years, quantitative analysis of homogeneous microvolumes has been performed with the aid of correction models which transform into mass concentrations C A the ratio k A between the emerging intensities from the specimen and a standard obtained for a characteristic line of element A:
Article
The field of uranium carboxylates has been studied for several decades and an important library of coordination complexes and network solids is now well defined. It mainly concerns the reactivity of hexavalent uranium (uranyl) with the different types of carboxylic acids containing monodentate or polydentate functions, aliphatic or aromatic carbon backbone, or hetero-systems offering other functionalities (N-donor, S-donor, phosphonates,...). A rich variety of molecular complexes or extended multi-dimensional networks (1D, 2D, 3D) has been identified and depends mainly on the equatorial connectivity of the uranyl cation (UO22+) in different coordination numbers (tetragonal, pentagonal or hexagonal bipyramid). The yl oxo groups remain relatively inert to condensation process (except rare case of cation-cation interaction). For lower oxidation state of uranium (+3, +4, +5), the knowledge is at the infancy stage since very few contributions are available in literature. Nevertheless, recent contributions have shown the possibilities of the reactivity of tetravalent uranium in relatively stable architectures, either at the molecular level, with high nuclearities (up to U-38), or engaged in three-dimensional frameworks. The scope of this review is a comprehensive presentation of the crystal structures resulting from the different types of complexation of uranium with carboxylic acid molecules (excepting oxalate ligand) and their classification as a function of the nuclearity of identified building units.
Article
Actinide oxalates are an important class of materials mainly for the nuclear industry. This review presents the crystal growth methods addressed to non-soluble actinide (III) and (IV) oxalates and to soluble actinyl oxalates. Actinide-oxalate discrete ions, one-dimensional coordination polymers and two- or three-dimensional frameworks are described for the different oxidation states of actinides in simple, double or triple actinide oxalates together with mixed actinide (IV)-lanthanide (III) or -actinide (III) and mixed ligands actinide oxalates. The main applications of actinide oxalates, particularly for radioactive waste management and nuclear fuel treatment and recycling are also reported.
Article
ZnV2O6, is monoclinic, space group C2/m, Cm or C2 from systematic absences, a = 9.2651(9), b = 3.5242(5), c = 6.5889(8) Å and β= 111.37(1)°. Chemical analysis showed that in ZnV2O6 crystals grown from the melt vanadium is partially reduced to the tetravalent state. This causes distorsion in the lattice and the observed piezoelectricity is related to this effect. A reasonable description of the “average” structure is achieved in the centrosymmetric space group C2/m.
Article
Two modifications of the new uranyl oxalate hydroxide dihydrate [UO2)2(C2O4)(OH)2(H2O)2] (1 and 2) and one form of the new uranyl oxalate hydroxide trihydrate [(UO2)2(C2O4)(OH)2(H2O)2]·H2O (3) were synthesized by hydrothermal methods and their structures determined from single-crystal X-ray diffraction data. The crystal structures were refined by full-matrix least-squares methods to agreement indices R(wR)=0.0372(0.0842) and 0.0267(0.0671) calculated for 1096 and 1167 unique observed reflections (I>2σ(I)), for α (1) and β (2) forms, respectively and to R(wR)=0.0301(0.0737) calculated for 2471 unique observed reflections (I>2σ(I)), for 3. The α-form of the dihydrate is triclinic, space group , , , , , , , , , β-form is monoclinic, space group , , , , , , . The trihydrate is monoclinic, space group , , , , , , . In the three structures, the coordination of uranium atom is a pentagonal bipyramid composed of dioxo UO2²⁺ cation perpendicular to five equatorial oxygen atoms belonging to one bidentate oxalate ion, one water molecule and two hydroxyl ions in trans configuration in 2 and in cis configuration in 1 and 3. The UO7 polyhedra are linked through hydroxyl oxygen atoms to form different structural building units, dimers [U2O10] obtained by edge-sharing in 1, chains [UO6]∞ and tetramers [U4O26] built by corner-sharing in 2 and 3, respectively. These units are further connected by oxalate entities that act as bis-bidentate to form one-dimensional chains in 1 and bi-dimensional network in 2 and 3. These chains or layers are connected in frameworks by hydrogen-bond arrays.
Article
The infrared and Raman spectra of anhydrous lead oxalate (PbC2O4) were recorded and discussed on the basis of its structural peculiarities. Some comparisons with other previously investigated metallic oxalates were made. Copyright © 2009 John Wiley & Sons, Ltd.
Article
The IR spectrum of calcium oxalate monohydrate is re-analysed, and the Raman spectrum presented for the first time. The IR and Raman spectra of an anhydrous phase of calcium oxalate are discussed in relation to the effects of dehydration and compared with the monohydrate.
Article
The crystal structures of uranyl minerals and inorganic uranyl compounds are important for understanding the genesis of U deposits, the interaction of U mine and mill tailings with the environment, transport of actinides in soils and the vadose zone, the performance of geological repositories for nuclear waste, and for the development of advanced materials with novel applications. Over the past decade, the number of inorganic uranyl compounds (including minerals) with known structures has more than doubled, and reconsideration of the structural hierarchy of uranyl compounds is warranted. Here, 368 inorganic crystal structures that contain essential U 6+ are considered (of which 89 are minerals). They are arranged on the basis of the topological details of their structural units, which are formed by the polymerization of polyhedra containing higher-valence cations. Overarching structural categories correspond to those based upon isolated polyhedra (8), fi nite clusters (43), chains (57), sheets (204), and frameworks (56) of polyhedra. Within these categories, structures are organized and compared upon the basis of either their graphical representations, or in the case of sheets involving sharing of edges of polyhedra, upon the topological arrangement of anions within the sheets.
Article
A correlation of O-H stretching frequencies (from infrared spectroscopy) with O…O and R…O bond lengths (from structural data) of minerals was established. References on 65 minerals yielded 125 data pairs for the d(O…0)-v correlation; due to rare or inaccurate data on proton positions, only 47 data pairs were used for the d(H…O)-v correlation. The data cover a wide range of wavenumbers from 1000 to 3738 cm−1 and O…O distances from 2.44 to 3.5 Å. They originate from silicates, (oxy)hydroxides, carbonates, sulfates, phosphates, and arsenates with OH−, H2O, or even H3O 2 − units forming very strong to very weak H bonds. The correlation function was established in the form v(cm−1) = 3592-304 · 109 · exp(-d(O…O)/0.1321), R 2 = 0.96. Because of deviations from ideal straight H bonds, i.e. bent or bifurcated geometry, dynamic proton behavior, but also due to factor group splitting and cationic effects, data scatter considerably around the regression line. The trends of previous correlation curves and of theoretical considerations were confirmed.
Article
{{The novel compound (UO2)(2)C2O4(OH)(2)(H2O)(2) (UrOx(2)A) and the previously studied compound UO2C2O4(H2O)(3) (UrOx(3)) have been synthesized by mild hydrothermal methods. Single crystal diffraction data collected at 125 K using MoK alpha radiation and a CCD-based area detector were used to solve and refine the crystal structures by full-matrix least-squares techniques to agreement indices (UrOx(2)A, UrOx(3)) wR(2) = 0.037, 0.049 for all data, and R1 = 0.015, 0.024 calculated for 1285, 2194 unique reflections respectively. The compound UrOx2A is triclinic, space group PI
Geology and uranium-vanadium deposits of the La Sal quadrangle
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The Geology and Production History of the Uranium Deposits in the White Canyon Mining District
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Uranium-vanadium deposits of the Slick Rock district, Colorado. United States Geological Survey Professional Paper
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Shawe D.R. (2011) Uranium-vanadium deposits of the Slick Rock district, Colorado. United States Geological Survey Professional Paper, 576-F.
Recherches sur l'uranium
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Péligot E. (1942) Recherches sur l'uranium. Annales de chimie et de physique, 5 (5), 5-51.
Crystal Structure refinement with SHELX
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The Geology and Production History of the Uranium Deposits in the White Canyon Mining District, San Juan County, Utah
  • Chenoweth
Uroxite, IMA 2018-100
  • Kampf
Metauroxite, IMA 2019-030
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