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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.

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Uranyl carbonates are one of the largest groups of secondary uranium(VI)-bearing natural phases being represented by 40 minerals approved by the International Mineralogical Association, overtaken only by uranyl phosphates and uranyl sulfates. Uranyl carbonate phases form during the direct alteration of primary U ores on contact with groundwaters enriched by CO2, thus playing an important role in the release of U to the environment. The presence of uranyl carbonate phases has also been detected on the surface of “lavas” that were formed during the Chernobyl accident. It is of interest that with all the importance and prevalence of these phases, about a quarter of approved minerals still have undetermined crystal structures, and the number of synthetic phases for which the structures were determined is significantly inferior to structurally characterized natural uranyl carbonates. In this work, we review the crystal chemistry of natural and synthetic uranyl carbonate phases. The majority of synthetic analogs of minerals were obtained from aqueous solutions at room temperature, which directly points to the absence of specific environmental conditions (increased P or T) for the formation of natural uranyl carbonates. Uranyl carbonates do not have excellent topological diversity and are mainly composed of finite clusters with rigid structures. Thus the structural architecture of uranyl carbonates is largely governed by the interstitial cations and the hydration state of the compounds. The information content is usually higher for minerals than for synthetic compounds of similar or close chemical composition, which likely points to the higher stability and preferred architectures of natural compounds.
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Meyrowitzite, Ca(UO 2)(CO 3) 2 ·5H 2 O, is a new mineral species from the Markey mine, Red Canyon, San Juan County, Utah, U.S.A. It is a secondary phase found on calcite-veined asphaltum in association with gypsum, markeyite, and rozenite. Meyrowitzite occurs as blades up to about 0.2 mm in length, elongate on [010], flattened on {100}, and exhibiting the forms {100}, {001}, {101}, {110}, and {011}. The mineral is yellow and transparent with vitreous luster and very pale yellow streak. Fluorescence under a 405 nm laser is from weak greenish yellow to moderate greenish blue. The Mohs hardness is ca. 2, tenacity is brittle, fracture is irregular, and there is one perfect cleavage, {101}. The measured density is 2.70(2) g/cm 3. The mineral is optically biaxial (+) with α = 1.520(2), β = 1.528(2), and γ = 1.561(2) (white light). The 2V(meas) = 53.0(6)°; weak dispersion, r > v; optical orientation: Z = b, Y ^ a ≈ 19° in obtuse β; pleochroism pale yellow, X ≈ Y < Z. Electron microprobe analyses provided the empirical formula Ca 0.94 (U 1.00 O 2)(CO 3) 2 ·5(H 2.02 O) on the basis of U = 1 and O = 13 apfu, as indicated by the crystal structure determination. Meyrowitzite is monoclinic, P2 1 /n, a = 12.376(3), b = 16.0867(14), c = 20.1340(17) Å, β = 107.679(13)°, V = 3819.3(12) Å 3 , and Z = 12. The structure (R 1 = 0.055 for 3559 I o > 2σI) contains both UO 7 pentagonal bipyramids and UO 8 hexagonal bipyramids, the latter participating in uranyl tricarbonate clusters (UTC). The two kinds of bipyramids and the carbonate groups link to form a novel corrugated heteropolyhedral sheet. This is the first structural characterization of a uranyl-carbonate mineral with a U:C ratio of 1:2. Meyrowitzite is apparently dimorphous with zellerite.
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Complexity is one of the important characteristics of crystal structures, which can be measured as the amount of Shannon information per atom or per unit cell. Since complexity may arise due to combination of different factors, herein we suggest a method of ladder diagrams for the analysis of contributions to structural complexity from different crystal-chemical phenomena (topological complexity, superstructures, modularity, hydration state, etc.). The group of minerals and inorganic compounds based upon the batagayite-type [M(TO
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Over the past four decades, the number of inorganic oxide and oxy-salt phases containing stoichiometric quantities of hexavalent uranium has increased exponentially from a few dozen to well over 700, and these structures have become well-known for their remarkable compositional diversity and topological variability. Considering the entirety of these compounds (i.e., crystal structures, conditions of synthesis, and geological occurrences) offers significant insight into the behavior of uranium in the solid state and in the nascent (typically aqueous) fluids. The structure hierarchy approach adopted here aims specifically to facilitate the recognition of useful patterns in the crystal-chemical behavior of hexavalent uranium (U⁶⁺). This work represents the third attempt at a structure hierarchy of U⁶⁺compounds, with the first two being those of Burns et al. (1996) and Burns (2005), which considered 180 and 368 structures, respectively. The current work is expanded to include the structures of 727 known, well-refined synthetic compounds (610) and minerals (117) that contain stoichiometric quantities of U⁶⁺. As in the previous works, structures are systematically ordered on the basis of topological similarity, as defined predominantly by the polymerization of high-valence cations. The updated breakdown is as follows: (1) isolated polyhedra (24 compounds/0 minerals); (2) finite clusters (70 compounds/10 minerals); (3) infinite chains (94 compounds/15 minerals); (4) infinite sheets (353 compounds/79 minerals); and (5) frameworks (186 compounds/13 minerals). Within each of these major categories, structures are sub-divided on the basis of increasing connectivity of uranium (nearly always uranyl) polyhedra. In addition to elucidating common trends in U⁶⁺ crystal chemistry, this structure hierarchy will serve as a comprehensive introduction for those not yet fluent in the domain of uranium mineralogy and inorganic, synthetic uranium chemistry.
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
The Gladstone–Dale relationship allows one to derive a compatibility index of the physical and chemical data used to characterize a mineral. Minerals of the following groups are reviewed: carbonates, sulfates, phosphates, vanadates, vanadium oxysalts, chromates, molybdates, tungstates, germanates, iodates, nitrates, oxalates, antimonites, antimonates, sulfites, halides, and borates. The mineral species in the Fair, Poor and Incomplete categories in these groups require further study.
Article
X-ray diffraction studies have revealed that K4UO2(CO3)3 is isostructural with (NH4)4UO2(CO3)3; the crystal is monoclinic with a = 10.247(3), b = 9.202(2), c = 12.226(3) Å, β = 95.11(2)°, Z = 4, and space group C2/c. Three carbonate anions are arranged in bidentate fashion in the equatorial plane of UO22+; one of these occupies a C2 site and the other two occupy C1 sites. All carbonates are significantly distorted from D3h symmetry. The binding of carbonates to uranyl is strong and thus the lattice can be considered to be composed of [UO2(CO3)3]4− anions and K+ cations. The Raman and infrared spectra exhibit fewer lines than predicted for such a crystal. Tentative assignments are suggested for the more prominent bands of the constituent polyatomic species.
Article
Diffuse reflectance (20,000–30,000 cm−1) and luminescence (18,000–21,000 cm−1) spectra of polycrystalline Na4[UO2(CO3)3] have been measured in the temperature range of 4.2–300 K; the i.r. (50–2000 cm−1) and Raman (50–2000 cm−1) spectra have been recorded at room temperature. The vibrational spectra exhibit all frequencies expected for a UO2L3 complex of D3h symmetry with bidentate ligands L. The symmetric and asymmetric stretching vibrations of the uranyl ion occur at wave numbers as low as 808 and 843 cm−1, respectively, indicating strong uranium ← carbonate bonding. The diffuse reflectance spectra consist of four overlapping electronic transitions, the lowest one with origin at 20,680 cm−1 is also seen in emission. The absorption bands are assigned to the spin and parity forbidden components of the πu→δu and πu→φu one-electron excitations. From the splitting of the excited configurations π3uδ1u and π3uφ1u the spin-orbit coupling constant is calculated to be ζ5ƒ = 1750 cm−1. Possible relationships between measurable spectroscopic properties of the uranyl ion and the strength of bonding in the equatorial plane are discussed.
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 crystal structure of liebigite, previously only incompletely known from a short note, has been determined from X-ray 4-circle diffractometer data and refined toR=0.030 for 3005 observed reflections. Liebigite from Joachimsthal, Bhmen, was used. It was found to crystallize in the polar orthorhombic space groupBba2–C 2v 17 witha=16.699(3),b=17.557(3),c=13.697(3) ,V=4016 3 and a cell content of 8 Ca2UO2(CO3)311H2O. The structure contains UO2(CO3)3 units which are linked by two kinds of CaO4(H2O)4 polyhedra and one kind of CaO3(H2O)4 polyhedron to form puckered Ca2UO2(CO3)38H2O layers parallel to (010). These layers are interconnected only by hydrogen bonds, both directly as well as via three additional interlayer H2O molecules, two of which show positional disorder.Die Kristallstruktur des Minerals Liebigit, die bis jetzt nur unzureichend bekannt war, wurde mit Rntgen-Vierkreisdiffraktometer-Daten bestimmt und fr 3005 beobachtete Reflexe aufR=0,030 verfeinert. Der untersuchte, von Joachimsthal, Bhmen, stammende Liebigit kristallisiert in der polaren rhombischen RaumgruppeBba2–C 2v 17 mita=16,699(3),b=17,557(3),c=13,697(3) ,V=4016 3 und einem Zellinhalt von 8 Ca2UO2(CO3)311H2O. Die Struktur enthlt UO2(CO3)3-Gruppen, die durch zwei Arten von CaO4(H2O)4-Polyedern und eine Art von CaO3(H2O)4-Polyedern zu buckeligen Ca2UO2(CO3)38H2O-Schichten parallel (010) verknpft sind. Diese Schichten sind nur durch Wasserstoffbrcken verbunden, und zwar sowohl direkt als auch mittels dreier zustzlicher freier Wassermolekle, von denen zwei eine Lagenfehlordnung aufweisen.
Leószilárdite, the first Na, Mg-containing uranyl carbonate from the Markey mine
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Olds T., Sadergaski L.R., Plášil J., Kampf A.R., Burns P., Steele I.M., Marty J., Carlson S.M. and Mills O.P. (2017) Leószilárdite, the first Na, Mg-containing uranyl carbonate from the Markey mine, San Juan County, Utah, USA. Mineralogical Magazine, 81, 743-754.
Vibrational spectroscopy of the uranyl minerals -infrared and Raman spectra of the uranyl minerals. II. Uranyl carbonates. Bulletin mineralogicko-petrologického oddělení Národního muzea (Praha)
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Čejka J. (2005) Vibrational spectroscopy of the uranyl minerals -infrared and Raman spectra of the uranyl minerals. II. Uranyl carbonates. Bulletin mineralogicko-petrologického oddělení Národního muzea (Praha), 13, 62-72 [and references therein, in Czech].
The geology and production history of the uranium deposits in the White Canyon Mining District
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Chenoweth W.L. (1993) The geology and production history of the uranium deposits in the White Canyon Mining District, San Juan County, Utah. Utah Geological Survey Miscellaneous Publication, 93-3.
CO 3 ) 2 ⋅5H 2 O, a new mineral with a novel uranylcarbonate sheet
  • Ca Meyrowitzite
Meyrowitzite, Ca(UO 2 )(CO 3 ) 2 ⋅5H 2 O, a new mineral with a novel uranylcarbonate sheet. American Mineralogist, 103, 603-610.
Paramarkeyite, IMA 2021-024. CNMNC Newsletter 62
  • Kampf
The Gladstone-Dale relationship – Part 1: derivation of new constants
  • Mandarino
The geology and production history of the uranium deposits in the White Canyon Mining District, San Juan County, Utah
  • Chenoweth
Vibrational spectroscopy of the uranyl minerals – infrared and Raman spectra of the uranyl minerals. II. Uranyl carbonates
  • Čejka