Über Ammonium‐Uranyl‐Vanadat und die Produkte seiner thermischen Zersetzung

Botto, I. L.; Baran, Enrique J.

doi:10.1002/zaac.19764260312

Cited by 21 publications

(3 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the low wavenumber region of the uranyl vanadates (Figure 2), a number of significant bands are observed. The most intense bands of the uranyl vanadates are observed around 370 cm -1 and are assigned to the δ bending modes of (V 2 O 2 ) units 22 The attribution of the bending modes of the (VO 3 ) units appears partly to be in agreement with the published infrared data from Botto et al [15,31]. These researchers assigned bands in the infrared spectra in the 612 to 670 cm -1 region to water librational modes.…”

Section: Resultssupporting

confidence: 82%

Vibrational spectroscopy of selected natural uranyl vanadates

Frost

Čejka

Weier

et al. 2005

Vibrational Spectroscopy

View full text Add to dashboard Cite

Dermot (2005) range and are assigned to the doubly degenerate ν 2 modes of the (UO 2 ) 2+ units. The study of the vibrational spectroscopy of uranyl vanadates is complicated by the overlap of bands from the (VO 3 ) and (UO 2 ) 2+ units. Raman spectroscopy has proven most useful in assigning bands to these two units since Raman bands are sharp and well separated as compared with infrared bands. The uranyl vanadate minerals are often found as crystals on a host matrix and Raman spectroscopy enables their in-situ characterisation without sample preparation.

show abstract

Section: Resultssupporting

confidence: 82%

Vibrational spectroscopy of selected natural uranyl vanadates

Frost

Čejka

Weier

et al. 2005

Vibrational Spectroscopy

View full text Add to dashboard Cite

show abstract

“…Low-valence cations and H 2 O groups in the interlayer region bind the sheets together. The carnotite-type sheet is chemically compliant and, combined with the wide range of possible interlayer cations, gives rise to a diverse group of minerals and synthetic compounds including sundry uranyl vanadates, − ,− uranyl niobates, neptunyl(VI) vanadates, and neptunyl(V) molybdates . Note that silicocarnotite is a structurally unrelated calcium silicate−phosphate …”

Section: Resultsmentioning

confidence: 99%

Syntheses, Structures, Magnetic Properties, and X-ray Absorption Spectra of Carnotite-type Uranyl Chromium(V) Oxides: A[(UO₂)₂Cr₂O₈](H₂O)_n (A = K₂, Rb₂, Cs₂, Mg; n = 0, 4)

et al. 2004

View full text Add to dashboard Cite

Four uranyl chromium(V) oxides were synthesized by mild hydrothermal methods and their structures were solved using single-crystal X-ray diffraction data. In these structures, U occurs in edge-sharing dimers of UO 7 uranyl pentagonal bipyramids, and Cr occurs in edge-sharing dimers of CrO 5 square pyramids. The two sets of dimers share edges, forming sheets of composition [(UO 2 ) 2 Cr 2 O 8 ] 2-that are topologically identical to uranyl divanadate sheets, [(UO 2 ) 2 V 2 O 8 ] 2-, that occur in compounds of the carnotite group. K 2 [(UO 2 ) 2 Cr 2 O 8 ] (KUCr), Rb 2 [(UO 2 ) 2 Cr 2 O 8 ] (RbUCr), and Cs 2 [(UO 2 ) 2 Cr 2 O 8 ] (CsUCr) are isostructural with K 2 [(UO 2 ) 2 V 2 O 8 ], and Mg[(UO 2 ) 2 Cr 2 O 8 ](H 2 O) 4 (MgUCr) is isostructural with Ni[(UO 2 ) 2 V 2 O 8 ]-(H 2 O) 4 . The stoichiometries of these compounds imply that Cr is present as chromium(V), which is supported by the results of bond valence analyses. EPR spectra and magnetic susceptibility data for KUCr are consistent with the presence of the d 1 cation chromium(V). The KUCr moments undergo a sharp transition from paramagnetic to antiferromagnetic behavior at T N ) 18.5 K. XAFS data for the U L 3 edge and XANES of the Cr K edge of KUCr yield coordinations and oxidation states consistent with the crystal structure analysis.

show abstract

“…The excess charge of aluminum is compensated by an hydroxyl ion, as is the excess charge of the two copper atoms in sengierite, Cu 2 (UO 2 ) 2 V 2 O 8 (OH) 2 ·6H 2 O . Many other materials pertaining to the carnotite group have been synthesized where M n + is an alkali metal, − NH 4 + , H 3 O + , Ag + , an alkaline-earth metal, − a divalent transition metal, or an organic template . Although the rare earths are found as impurities in some uraninite ores and as a major component in natural minerals such as the carbonate bijvoetite, there have been no natural uranyl vanadate minerals containing rare earths identified so far, to our knowledge.…”

Section: Introductionmentioning

confidence: 99%

Structural Evolution in the Rare-Earth Uranyl Vanadates Ln₂[(UO₂)₂V₂O₈]₃·nH₂O, Singularity of the Lanthanum Compound, and Single-Crystal to Single-Crystal Partial Dehydration

mer

Obbade

Devaux

et al. 2019

Crystal Growth & Design

View full text Add to dashboard Cite

A family of compounds with general chemical formula Ln 2 [(UO 2 ) 2 V 2 O 8 ] 3 •nH 2 O, where Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Er, Yb, Y has been hydrothermally synthesized and structurally characterized. The structures of all these compounds can be described as the stacking of carnotite-type uranyl vanadate layers pillared by lanthanide−oxygen polyhedra. Except for La, they are isostructural, and the crystal structure determination of Ndshows that the ud/du/du geometrical isomers of the uranyl vanadate layers are pillared by Nd(O yl ) 2 (H 2 O) 7 and Y(O yl ) 2 (H 2 O) 6 polyhedra, respectively, through interactions between the lanthanide ion and the oxygens O yl of two vanadyl ions forming VO yl −Ln−O yl V entities. In the La compound, the ud/du geometrical isomers of the uranyl vanadate layers are pillared by La(O yl ) 2 (H 2 O) 8 , through interactions between the lanthanum ion and the oxygens O yl of one vanadyl and one uranyl ion, forming UO yl −La−O yl V entities. Thermogravimetric and high-temperature X-ray diffraction studies show that the dehydration of the La compound is also singular; while the dehydration of other compounds involves a regular decrease in the interlayer space, for La it is realized through structural transitions. Upon partial dehydration, the La crystalline material undergoes a single-crystal to single-crystal transition between the 20-and 6-hydrates. Despite very large variation of the unit cell parameters and volume (ΔV = −27.8%!), the crystal remained of sufficient quality to allow the crystal structure determination of the hexahydrate. The total dehydration is reversible.

show abstract

Über Ammonium‐Uranyl‐Vanadat und die Produkte seiner thermischen Zersetzung

Cited by 21 publications

References 14 publications

Vibrational spectroscopy of selected natural uranyl vanadates

Vibrational spectroscopy of selected natural uranyl vanadates

Syntheses, Structures, Magnetic Properties, and X-ray Absorption Spectra of Carnotite-type Uranyl Chromium(V) Oxides: A[(UO₂)₂Cr₂O₈](H₂O)_n (A = K₂, Rb₂, Cs₂, Mg; n = 0, 4)

Structural Evolution in the Rare-Earth Uranyl Vanadates Ln₂[(UO₂)₂V₂O₈]₃·nH₂O, Singularity of the Lanthanum Compound, and Single-Crystal to Single-Crystal Partial Dehydration

Contact Info

Product

Resources

About

Über Ammonium‐Uranyl‐Vanadat und die Produkte seiner thermischen Zersetzung

Cited by 21 publications

References 14 publications

Vibrational spectroscopy of selected natural uranyl vanadates

Vibrational spectroscopy of selected natural uranyl vanadates

Syntheses, Structures, Magnetic Properties, and X-ray Absorption Spectra of Carnotite-type Uranyl Chromium(V) Oxides: A[(UO2)2Cr2O8](H2O)n (A = K2, Rb2, Cs2, Mg; n = 0, 4)

Structural Evolution in the Rare-Earth Uranyl Vanadates Ln2[(UO2)2V2O8]3·nH2O, Singularity of the Lanthanum Compound, and Single-Crystal to Single-Crystal Partial Dehydration

Contact Info

Product

Resources

About

Syntheses, Structures, Magnetic Properties, and X-ray Absorption Spectra of Carnotite-type Uranyl Chromium(V) Oxides: A[(UO₂)₂Cr₂O₈](H₂O)_n (A = K₂, Rb₂, Cs₂, Mg; n = 0, 4)

Structural Evolution in the Rare-Earth Uranyl Vanadates Ln₂[(UO₂)₂V₂O₈]₃·nH₂O, Singularity of the Lanthanum Compound, and Single-Crystal to Single-Crystal Partial Dehydration