Lakebogaite, CaNaFe23+H(UO2)2(PO4)4(OH)2(H2O)8, a new uranyl phosphate with a unique crystal structure from Victoria, Australia

Mills, Stuart J.; Birch, William D.; Kolitsch, Uwe; Mumme, W. G.; Grey, Ian E.

doi:10.2138/am.2008.2706

Cited by 17 publications

(7 citation statements)

References 17 publications

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“…Thus, Sr uranyl selenite possesses the same (ud) ∞ sequence, as in a previous case, while the Na-bearing compound has a (u) ∞ sequence. This type of topology has been observed in several synthetic uranyl chromates, phosphates, and arsenates, as well as in lakebogaite, CaNa(Fe 3+ ) 2 [(H(UO 2 ) 2 (PO 4 ) 4 (OH) 2 ](H 2 O) 8 [76].…”

Section: Topological Analysismentioning

confidence: 53%

Crystal Chemistry and Structural Complexity of Natural and Synthetic Uranyl Selenites

et al. 2019

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Comparison of the natural and synthetic phases allows an overview to be made and even an understanding of the crystal growth processes and mechanisms of the particular crystal structure formation. Thus, in this work, we review the crystal chemistry of the family of uranyl selenite compounds, paying special attention to the pathways of synthesis and topological analysis of the known crystal structures. Comparison of the isotypic natural and synthetic uranyl-bearing compounds suggests that uranyl selenite mineral formation requires heating, which most likely can be attributed to the radioactive decay. Structural complexity studies revealed that the majority of synthetic compounds have the topological symmetry of uranyl selenite building blocks equal to the structural symmetry, which means that the highest symmetry of uranyl complexes is preserved regardless of the interstitial filling of the structures. Whereas the real symmetry of U-Se complexes in the structures of minerals is lower than their topological symmetry, which means that interstitial cations and H 2 O molecules significantly affect the structural architecture of natural compounds. At the same time, structural complexity parameters for the whole structure are usually higher for the minerals than those for the synthetic compounds of a similar or close organization, which probably indicates the preferred existence of such natural-born architectures. In addition, the reexamination of the crystal structures of two uranyl selenite minerals guilleminite and demesmaekerite is reported. As a result of the single crystal X-ray diffraction analysis of demesmaekerite, Pb 2 Cu 5 [(UO 2 ) 2 (SeO 3 ) 6 (OH) 6 ](H 2 O) 2 , the H atoms positions belonging to the interstitial H 2 O molecules were assigned. The refinement of the guilleminite crystal structure allowed the determination of an additional site arranged within the void of the interlayer space and occupied by an H 2 O molecule, which suggests the formula of guilleminite to be written as Ba 3 . occurrence is limited to just a few localities. First, these are Musonoi and Shinkolobwe mines in DR Congo [6], two of the minerals were only found in the Repete mine (San Juan County, Utah, USA) [5], and a few more occurrences in Europe could be mentioned (small uranium deposit Zálesí in the Czech Republic, Liauzun in France, and La Creusaz U prospect in Switzerland) [8]. Nevertheless, apart from mineralogy, uranyl selenites are of great interest from the geochemical and radiochemical points of view. It is known that fission products contain 53 g per ton [9] of long-lived 79 Se isotope with a half-life of 1.1 × 10 6 years [10] after three years of nuclear fuel irradiation in the reactor. Thus, an understanding of the processes of mineral formation in nature and their synthetic analogs in laboratories can help in the processing of nuclear wastes. Crystal chemical and structural investigations are key points in such a material's scientific studies due to the essential knowledge of how the variation in the chemical composi...

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Section: Topological Analysismentioning

confidence: 53%

Crystal Chemistry and Structural Complexity of Natural and Synthetic Uranyl Selenites

et al. 2019

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“…The most recent overview on the mineralogy and crystallography of uranium has been given by Krivovichev and Plášil (2013). Many new uranium minerals with a diverse chemical composition and fascinating structures have been described in the past few years (e.g., Sejkora and Čejka 2007;Mills et al 2008;Walenta et al 2009;Meisser et al 2010;Kampf et al 2010;Plášil et al 2010a;Brugger et al 2011;Plášil et al 2011a, b;Pekov et al 2012a, b;Plášil et al 2012a, b, c;Walenta and Theye 2012;Kampf et al 2013;Pekov et al 2013;Plášil et al 2013a, b, c). Nowadays, more than 260 minerals (!)…”

Section: Mineralogy and Crystallographymentioning

confidence: 99%

Oxidation-hydration weathering of uraninite: the current state-of-knowledge

Plášil¹

2014

Jour. Geosci.

129

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Oxidation-hydration weathering of uraninite, the most common U-bearing mineral in nature, comprises various physical and chemical processes that lead to the destruction of the fluorite-type structure of uraninite where U is present as tetravalent. This results in replacement of uraninite by weathering products containing U in hexavalent form, i.e. as uranyl ion, UO 2 2+. The final assemblage of the weathering products, uranyl minerals, and their compositions depend on the various factors, namely the composition of the primary minerals and percolating oxidizing fluids that cause the alteration. The knowledge of such processes and stabilities of the uranium minerals is of the great interest namely due to demand for U as the energy source. During the past decade there has been substantial progress in understanding the mineralogy, crystallography and thermodynamics of uranyl minerals and thus a substantially improved understanding of the weathering processes themselves. This review aims to summarize the state-of-art of the current knowledge on uranium-related topics as well and identify some of the important questions that remain unanswered.The following text is dedicated to Jiří Čejka on occasion of his 85 th birthday anniversary. Jiří greatly contributed not only to the spectroscopy and mineralogy of uranyl minerals, but also to the questions pertaining their origin and stability. Many important issues were addressed, even if briefly, in the pioneering book "Secondary Uranium Minerals" by Čejka and Urbanec (1990) which has served, for a long-time, as a guide for beginning uranium mineralogists.

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“…Chemical analyses, p-XRD, and microscopy (Table S5, Figure S1 and Figure S2) indicated that single phases of NaUAs and KUAs were obtained using the diffusion method described in the Materials and Methods section. Single phase crystals of uranyl arsenates of the meta-autunite group with mono and divalent cations have also been identified in previous studies after synthesis using the same method. , The discrepancy between the cation’s concentration with the microprobe and acid digestion analyses for KUAs is attributed to instability of the compound during electron beam irradiation, as is typical for similar compounds under the microprobe beam …”

Section: Resultsmentioning

confidence: 69%

Solubility and Thermodynamic Investigation of Meta-Autunite Group Uranyl Arsenate Solids with Monovalent Cations Na and K

Meza

Gonzalez‐Estrella

Burns

et al. 2022

Environ. Sci. Technol.

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We investigated the aqueous solubility and thermodynamic properties of two meta-autunite group uranyl arsenate solids (UAs). The measured solubility products (log K sp ) obtained in dissolution and precipitation experiments at equilibrium pH 2 and 3 for NaUAs and KUAs ranged from −23.50 to −22.96 and −23.87 to −23.38, respectively. The secondary phases (UO 2 )(H 2 AsO 4 ) 2 (H 2 O) (s) and trogerite, (UO 2 ) 3 (AsO 4 ) 2 • 12H 2 O (s) , were identified by powder X-ray diffraction in the reacted solids of KUA precipitation experiments (pH 2) and NaUAs dissolution and precipitation experiments (pH 3), respectively. The identification of these secondary phases in reacted solids suggest that H 3 O + co-occurring with Na or K in the interlayer region can influence the solubilities of uranyl arsenate solids. The standard-state enthalpy of formation from the elements (ΔH f-el ) of NaUAs is −3025 ± 22 kJ mol −1 and for KUAs is −3000 ± 28 kJ mol −1 derived from measurements by drop solution calorimetry, consistent with values reported in other studies for uranyl phosphate solids. This work provides novel thermodynamic information for reactive transport models to interpret and predict the influence of uranyl arsenate solids on soluble concentrations of U and As in contaminated waters affected by mining legacy and other anthropogenic activities.

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Lakebogaite, CaNaFe23+H(UO2)2(PO4)4(OH)2(H2O)8, a new uranyl phosphate with a unique crystal structure from Victoria, Australia

Cited by 17 publications

References 17 publications

Crystal Chemistry and Structural Complexity of Natural and Synthetic Uranyl Selenites

Crystal Chemistry and Structural Complexity of Natural and Synthetic Uranyl Selenites

Oxidation-hydration weathering of uraninite: the current state-of-knowledge

Solubility and Thermodynamic Investigation of Meta-Autunite Group Uranyl Arsenate Solids with Monovalent Cations Na and K

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