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Journal ArticleDOI

Studies of layered uranium (VI) compounds. VI. Ionic conductivities and thermal stabilities of MUO2PO4 · nH2O, where M = H, Li,Na,K,NH4 or 12 Ca, and where n is between 0 and 4

15 Mar 1981-Journal of Solid State Chemistry (Academic Press)-Vol. 37, Iss: 1, pp 37-43
TL;DR: In this article, the authors measured the ionic conductivities of pressed pellets of the layered compounds MUO2PO4 · nH2O, and correlated the results with TGA data.
About: This article is published in Journal of Solid State Chemistry.The article was published on 1981-03-15. It has received 46 citations till now. The article focuses on the topics: Qualitative inorganic analysis.
Citations
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Journal ArticleDOI
TL;DR: In this article, two uranyl phenylphosphonates, UO2(HO3PC6H5)2(H2O)]2·8H 2O (1) and UO 2(HO 3PC 6H5 )2·2CH3CH2OH (2), have been synthesized and their structures solved by single-crystal methods.
Abstract: Two uranyl phenylphosphonates, [UO2(HO3PC6H5)2(H2O)]2·8H2O (1) and UO2(HO3PC6H5)2·2CH3CH2OH (2), have been synthesized and their structures solved by single-crystal methods. Both compounds crystallize in the triclinic space group P1. Unit cell parameters are a = 11.724(4) A, b = 16.676(8) A, c = 11.375(2) A, α = 101.61(5)°, β = 106.76(3)°, γ = 102.57(4)°, and Z = 2 for compound 1 and a = 9.332(6) A, b = 11.48(1) A, c = 5.672(2) A, α = 98.98(6)°, β = 92.78(5)°, γ = 108.54(5)°, and Z = 1 for compound 2. In both compounds the metal to phosphonate ratio is 1:2, and they both form linear chains. Each metal atom in these structures is surrounded by four oxygens of four different phosphonate groups which take up the metal's equatorial positions. However, in compound 1 an additional oxygen of a water molecule binds to the uranium atom in the equatorial plane. This leads to a distorted pentagonal bipyramidal geometry of uranium in compound 1 and to a distorted octahedral geometry of uranium in compound 2. Adjacen...

121 citations

Journal ArticleDOI
TL;DR: In this article, a mixture of UO2MoO4 and MoO3 was synthesized by using anionic uranium molybdate sheets separated by cationic organic templates.
Abstract: Single crystals of (NH3(CH2)3NH3)(H3O)2(UO2)3(MoO4)5 (1), C(NH2)3(UO2)(OH)(MoO4) (2), (C4H12N2)(UO2)(MoO4)2 (3) and (C5H14N2)(UO2)(MoO4)2·H2O (4) have been synthesized hydrothermally by using UO2(CH3COO)2·2H2O, (NH4)2Mo2O7, HF(aq), H2O, and the respective organic template. The materials have layered structures with anionic uranium molybdate sheets separated by cationic organic templates. Compound 1 has an unprecedented uranium molybdate topology, whereas 2 is structurally related to johannite, Cu[(UO2)2(SO4)2(OH)2](H2O)8, and 3 and 4 have layer topologies similar to zippiete, K2[UO2(MoO4)2]. Thermogravimetric measurements indicate all that four materials, after template loss, form a crystalline mixture of UO2MoO4 and MoO3. Crystal data: (NH3(CH2)3NH3)(H3O)2(UO2)3(MoO4)5, orthorhombic, space group Pbnm (No. 62), with a = 10.465(1) A, b = 16.395(1) A, c = 20.241(1) A, and Z = 4; C(NH2)3(UO2)(OH)(MoO4), monoclinic, space group P21/c (No. 14), with a = 15.411(1) A, b = 7.086(1) A, c = 18.108(1) A, β = 113.12...

105 citations

Journal ArticleDOI
TL;DR: The hydrothermal reactions of thorium nitrate and uranyl acetate with carboxyphenylphosphonic acid and HF result in the formation of ThF and UO, respectively, which display vibronically coupled fluorescence and the potential for energy transfer from the ligand to the charge-transfer bands of the uranyl cations.
Abstract: The hydrothermal reactions of thorium nitrate and uranyl acetate with carboxyphenylphosphonic acid and HF result in the formation of ThF2(PO3C6H4CO2H) and UO2(PO3HC6H4CO2H)2·2H2O, respectively. ThF...

79 citations

Journal ArticleDOI
TL;DR: Two uranyl nanotubules with elliptical cross sections were synthesized in high yield from complex and large oxoanions using hydrothermal reactions of uranyl salts with 1,4-benzenebisphosphonic acid and Cs(+) or Rb(+) cations in the presence of hydrofluoric acid to show high stability and exceptional ion-exchange properties toward monovalent cations.
Abstract: Two uranyl nanotubules with elliptical cross sections were synthesized in high yield from complex and large oxoanions using hydrothermal reactions of uranyl salts with 1,4-benzenebisphosphonic acid or 4,4′-biphenylenbisphosphonic acid and Cs+ or Rb+ cations in the presence of hydrofluoric acid. Disordered Cs+/Rb+ cations and solvent molecules are present within and/or between the nanotubules. Ion-exchange experiments with A2{(UO2)2F(PO3HC6H4C6H4PO3H)(PO3HC6H4C6H4PO3)}·2H2O (A = Cs+, Rb+), revealed that A+ cations can be exchanged for Ag+ ions. The uranyl phenyldiphosphonate nanotubules, Cs3.62H0.38[(UO2)4{C6H4(PO2OH)2}3{C6H4(PO3)2}F2]·nH2O, show high stability and exceptional ion-exchange properties toward monovalent cations, as demonstrated by ion-exchange studies with selected cations, Na+, K+, Tl+, and Ag+. Studies on ion-exchanged single crystal using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS) provide evidence for chemical zonation in Cs3.62H0.38[(UO2)4{C6H4(PO2OH)...

72 citations

Journal ArticleDOI
TL;DR: In this article, a series of layered uranyl diphosphonate compounds, including Me4Ubbp and Et2Me2UbbP, are shown to contain UO6F and UO7 pentagonal bipyramids within dimers.
Abstract: The hydrothermal treatment of uranyl nitrate and 1,4-benzenebisphosphonic acid with a variety of aliphatic amines (tetramethylammonium hydroxide, tetraethylammonium hydroxide, and diethyldimethylammonium hydroxide) and small quantities of hydrofluoric acid at 200 °C results in the crystallization of a series of layered uranyl diphosphonate compounds, [(CH3)4N][(UO2)3(O3PC6H4PO3H)2F(H2O)]·0.5H2O (Me4Ubbp), [(CH3CH2)4N]{(UO2)[C6H4(PO3H)(PO3H1.5)]2(H2O)} (Et4Ubbp), and [(CH3CH2)2N(CH3)2][(UO2)3(O3PC6H4PO3H)2F(H2O)] (Et2Me2Ubbp). All these new compounds have layered structures, but the structures of Me4Ubbp and Et2Me2Ubbp are similar in that they both contain UO6F and UO7 pentagonal bipyramids within dimers that are bridged by the phosphonate into a three-dimensional structure. The structure of Et4Ubbp contains a single crystallographically unique UO7 unit. The edge-sharing pentagonal bipyramids are linked into chains formulated as {(UO2)[C6H4(PO3H)(PO3H1.5)]2(H2O)}1−. The voids in these structures are filled...

72 citations

References
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Journal ArticleDOI
TL;DR: In this article, the Im3 phase of high pressure KSbO3, the defect-pyrochlore structure illustrated by RbMgAlF6, and the carnegieite structure of high-temperature NaAlSiO4 were investigated.

1,733 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the layered hydrate HUO2PO4 is a rapid proton conductor with a room temperature conductivity of 4 × 10−3ohm−1cm−1.

136 citations

Journal ArticleDOI
TL;DR: In this paper, a Grotthus-type mechanism of conduction is proposed which involves intermolecular transfer steps (hopping) and inter-parallel transfer steps in comparable numbers, the former facilitated by the high concentration of H 3 O + ions in the structure, and the latter most likely facilitated by high H-bond vacancies.

132 citations

Journal ArticleDOI
TL;DR: In this paper, single-crystal measurements on hydrogen uranyl phosphate tetrahydrate, HUO 2 PO 4 ·4H 2 O (HUP), have confirmed that the high proton conductivity is a bulk characteristic.

76 citations