115813-40-6Relevant articles and documents
Crystal and Electronic Structures of A2NaIO6Periodate Double Perovskites (A = Sr, Ca, Ba): Candidate Wasteforms for I-129 Immobilization
Dixon Wilkins, Malin C.,George, Jonathan,Hyatt, Neil C.,Kim, Eunja,Kirk, Cameron,Knight, Kevin S.,Montoya, Eduardo,O'Sullivan, Sarah E.,Sun, Shi-Kuan,Weck, Philippe F.
, p. 18407 - 18419 (2020)
The synthesis, structure, and thermal stability of the periodate double perovskites A2NaIO6 (A= Ba, Sr, Ca) were investigated in the context of potential application for the immobilization of radioiodine. A combination of X-ray diffraction and neutron diffraction, Raman spectroscopy, and DFT simulations were applied to determine accurate crystal structures of these compounds and understand their relative stability. The compounds were found to exhibit rock-salt ordering of Na and I on the perovskite B-site; Ba2NaIO6 was found to adopt the Fm-3m aristotype structure, whereas Sr2NaIO6 and Ca2NaIO6 adopt the P21/n hettotype structure, characterized by cooperative octahedral tilting. DFT simulations determined the Fm-3m and P21/n structures of Ba2NaIO6 to be energetically degenerate at room temperature, whereas diffraction and spectroscopy data evidence only the presence of the Fm-3m phase at room temperature, which may imply an incipient phase transition for this compound. The periodate double perovskites were found to exhibit remarkable thermal stability, with Ba2NaIO6 only decomposing above 1050 °C in air, which is apparently the highest recorded decomposition temperature so far recorded for any iodine bearing compound. As such, these compounds offer some potential for application in the immobilization of iodine-129, from nuclear fuel reprocessing, with an iodine incorporation rate of 25-40 wt%. The synthesis of these compounds, elaborated here, is also compatible with both current conventional and future advanced processes for iodine recovery from the dissolver off-gas.
Ion Exchange of Layered Alkali Titanates (Na2Ti3O7, K2Ti4O9, and Cs2Ti5O11) with Alkali Halides by the Solid-State Reactions at Room Temperature
Ogawa, Makoto,Saothayanun, Taya Ko,Sirinakorn, Thipwipa Tip
, p. 4024 - 4029 (2020)
Ion exchange of layered alkali titanates (Na2Ti3O7, K2Ti4O9, and Cs2Ti5O11) with several alkali metal halides surprisingly proceeded in the solid-state at room temperature. The reaction was governed by thermodynamic parameters and was completed within a shorter time when the titanates with a smaller particle size were employed. On the other hand, the required time for the ion exchange was shorter in the cases of Cs2Ti5O11 than those of K2Ti4O9 irrespective of the particle size of the titanates, suggesting faster diffusion of the interlayer cation in the titanate with lower layer charge density.
Origin of the thermal desorption peaks of gases in NaI above 180°C
Sofronov,Kudin,Voloshko, A. Yu.,Kudin,Shishkin
, p. 1314 - 1318 (2009)
We analyze the origin of the water desorption peaks in NaI above the temperature stability range of the crystalline hydrate NaI ? 2H 2O. The two water desorption peaks at t ≥ 180°C are shown to arise from the decomposition of aqua complexes bas
Chemical synthesis of aluminum nitride nanorods in an autoclave at 200 °C
Fu, Li,Xu, Liqiang,Duan, Junling,Li, Ting,Yang, Lishan,Qian, Yitai
, p. 622 - 623 (2009)
Hexagonal phase aluminum nitride (AlN) nanorods have been prepared via a chemical reaction from Al, I2, and NaN3 in an autoclave at 200°C. Electron microscopy investigations show that the nanorods have diameters ranging from 50 to 100nm and lengths up to several micrometers. Thermal gravimetric analysis reveals that the sample has good thermal stability below 600°C, and room-temperature photoluminescence (PL) of the sample shows a strong emission peak centered at 397 nm. Copyright
Addition compounds of alkali metal hydrides. 22. Convenient procedures for the preparation of lithium borohydride from sodium borohydride and borane-dimethyl sulfide in simple ether solvents
Brown, Herbert C.,Choi, Yong Moon,Narasimhan
, p. 3657 - 3661 (1982)
The preparation of LiBH4 in various ether solvents from the readily available reagents NaBH4 and lithium halides is described. The reactivity of lithium halides toward the metathesis reaction generally follows the order LiBr > LiI > LiCl. The heterogeneous reactions proceed satisfactorily with vigorous magnetic stirring. However, attempting to increase the scale of the preparations utilizing mechanical stirrers resulted in incomplete reactions and decreased yield. On the other hand, when the heterogeneous mixture was stirred with mechanical stirrers fitted with Teflon paddles and a mass of glass beads, the rate of the reaction increased considerably, producing quantitative yields of LiBH4 in greatly decreased reaction times. The ease of conversion of NaBH4 into LiBH4 in various solvents follows the order isopropylamine > 1,3-dioxolane > monoglyme > tetrahydrofuran ≈ ether. The isolation of solvent-free LiBH4 from the various solvates was attempted under different conditions. In most cases, normal distillation at 100 or 150°C produced a strong 1:1 solvate, LiBH4·solvent. Only in the case of ethyl ether is the solvent of solvation readily removed at 100°C at atmospheric pressure. In the other cases, both higher temperatures, up to 150°C, and lower pressures, down to 0.1 mm, are required to produce the unsolvated material. Thus the ease of isolating unsolvated LiBH4 is ethyl ether > IPA > THF > 1,3-D ≈ MG. Consequently, ethyl ether is the medium of choice for the preparation of LiBH4 by the metathesis of NaBH4 and LiBr. LiBH4 can also be conveniently prepared by the reaction of LiH with H3B·SMe2 in ethyl ether. Dimethyl sulfide is readily removed, along with ethyl ether of solvation, at 100°C (atmospheric pressure). These procedures make LiBH4 readily available.
Sm2O2I - A new mixed-valence samarium(II,III) oxide halide
Ryazanov, Mikhail,Hoch, Constantin,Mattausch, Hansjuergen,Simon, Arndt
, p. 2385 - 2388 (2006)
Dark red single crystals of Sm2O2I were obtained from a reaction of SmI2 (in the presence of SmOI) and Na in a sealed tantalum ampoule at 650 °C. The title compound crystallizes in the monoclinic system (C2/m, Z = 4, a = 12.639(2), b = 4.100(1), c = 9.762(3) A, β = 117.97(2)°). The structure consists of corrugated [Sm 2+Sm3+(O2-)2]+ layers of edge and vertex-connected Sm4O tetrahedral units with I- anions separating the layers.
Improved synthetic routes to layered NaxCoO2 oxides
Cushing, Brian L.,Wiley, John B.
, p. 1199 - 1207 (1999)
Improved synthetic routes to four NaxCoO2 (0.52 ≤ x ≤ 1) oxides of varying compositions and structures are presented. A combination of ceramic techniques and oxidative deintercalation reactions were used to access this series. Comparisons are made to previously reported preparative methods and differences in unit cell parameters discussed.
Multistep soft chemistry method for valence reduction in transition metal oxides with triangular (CdI2-type) layers
Blakely, Colin K.,Bruno, Shaun R.,Poltavets, Viktor V.
, p. 2797 - 2800 (2014)
Transition metal (M) oxides with MO2 triangular layers demonstrate a variety of physical properties depending on the metal oxidation states. In the known compounds, metal oxidation states are limited to either 3+ or mixed-valent 3+/4+. A multistep soft chemistry synthetic route for novel phases with M2+/3+O2 triangular layers is reported.
Synthesis and structures of magnesium alanate and two solvent adducts
Fichtner, Maximilian,Fuhr, Olaf
, p. 286 - 296 (2002)
A synthesis and purification method for Mg(AlH4)2 is presented, which is based on a metathesis reaction of NaAlH4 and MgCl2 in diethyl ether and subsequent purification procedure leading to a high yield of the monoether adduct of Mg(AlH4)2. After removal of the solvent, the alanate has been obtained as a nanocrystalline material with a yield of 81% and a purity of 95%. Crystal structures were determined and discussed for the solvent adducts Mg(AlH4)2·4THF and Mg(AlH4)2·Et2O. A proposition is made for the structure of Mg(AlH4)2. Elsevier Science B.V. All rights reserved.
New synthesis route to and physical properties of lanthanum monoiodide
Ryazanov, Mikhail,Kienle, Lorenz,Simon, Arndt,Mattausch, Hansjuergen
, p. 2068 - 2074 (2006)
A fast procedure to produce Lal by reduction of Lal2 or Lal 3 in a Na melt under argon at 550°C is given. The structural studies performed by means of powder X-ray diffraction as well as transmission electron microscopy are consistent with previous single-crystal results. Measurements of the electrical resistance on polycrystalline samples reveal metallic behavior for Lal in the range 10-300 K. Upon cooling, a small maximum in the resistivity has been observed at 67 K. This anomaly disappears upon heating a sample, however, yielding a hysteresis in ρ(T) above 70 K. From the Pauli susceptibility, an electron density of states at the Fermi level of about 0.3 eV-1·formula unit-1 has been estimated, as compared with a value of 1.0 eV-1·formula unit-1 derived from ab initio LMTO band structure calculations.
