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.
Eddy, R. D.,Menzies, A. W. C.
, p. 207 - 235 (1940)
Hawthorne, M. F.,Miller, J. J.
, p. 500 (1960)
Feigl,Chargaff,Sommer,Curtius,Rissom
, p. 376 - 380 (1928)
Briggs, T. R.,Geigle, W. F.
, p. 373 - 377 (1940)
Eder, J. M.,Ulm, G.
, (1882)
Feigl, F.,Leitmeier, H.
, p. 241 (1928)
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.
Feigl, F.
, p. 369 - 369 (1928)
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.
Bennet, F. W.,Emeleus, H. J.,Haszeldine, R. N.
, (1953)
Watt, G. W.
, p. 289 - 315 (1950)
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.
Static observation of the interphase between NaBH4 and LiI during the conversion reaction
Hihara, Takehiko,Miyagawa, Reina,Miyazaki, Reona,Onishi, Keita
, (2021/08/10)
To determine the synthesis conditions for NaI–NaBH4–LiI solid solutions in a single phase, the conversion reaction of NaBH4 ?+ ?LiI → NaI ?+ ?LiBH4 was investigated by preparing mixed pellets of NaBH4/LiI. The extent of the reaction was investigated under different reaction temperatures and pressures. Although it was not possible to completely suppress the conversion reaction in this study, the low temperature and high-pressure conditions were shown to be favorable to avoid the presence of LiBH4. A significant point is that the conversion reaction was investigated in a static condition in the form of pellets, whereas most of the metal borohydride-halide composites have been fabricated by ball-milling. The microstructure of NaBH4/LiI mixed pellets at different ageing times was observed by scanning electron microscope (SEM), Auger electron spectroscopy (AES), wavelength dispersive X-ray spectroscopy (WDS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). The analysis revealed that the reaction interphase between NaBH4 and LiI occurs in the order of LiI/NaI/LiBH4/NaBH4. It was clearly confirmed that the growth of the NaI layer continued with time even at room temperature. In conjunction with the array of the interphase, the diffusion of Na+ in LiBH4 appears to be a necessary condition for the growth of the NaI layer. The present results suggest that a detailed investigation of the conversion reaction between other metal borohydrides and halides (for example, CeCl3/LiBH4, ZrCl4/KBH4, etc.) in the static condition would likely reveal the diffusion of the new ions in the existing compounds.
