Astatine compounds are compounds that contain the element astatine (At). As this element is very radioactive, few compounds have been studied. Less reactive than iodine, astatine is the least reactive of the halogens.[1] Its compounds have been synthesized in nano-scale amounts and studied as intensively as possible before their radioactive disintegration. The reactions involved have been typically tested with dilute solutions of astatine mixed with larger amounts of iodine. Acting as a carrier, the iodine ensures there is sufficient material for laboratory techniques (such as filtration and precipitation) to work.[2][3][a] Like iodine, astatine has been shown to adopt odd-numbered oxidation states ranging from −1 to +7.
The chemistry of astatine is "clouded by the extremely low concentrations at which astatine experiments have been conducted, and the possibility of reactions with impurities, walls and filters, or radioactivity by-products, and other unwanted nano-scale interactions".[6] Many of its apparent chemical properties have been observed using tracer studies on extremely dilute astatine solutions,[7][8] typically less than 10−10 mol·L−1.[9] Some properties, such as anion formation, align with other halogens.[10] Astatine has some metallic characteristics as well, such as plating onto a cathode,[b] and coprecipitating with metal sulfides in hydrochloric acid.[12] It forms complexes with EDTA, a metal chelating agent,[13] and is capable of acting as a metal in antibodyradiolabeling; in some respects, astatine in the +1 state is akin to silver in the same state. Most of the organic chemistry of astatine is, however, analogous to that of iodine.[14] It has been suggested that astatine can form a stable monatomic cation in aqueous solution.[12][15]
^Aten, A. H. W. Jr.; Doorgeest, T.; Hollstein, U.; Moeken, H. P. (1952). "Section 5: Radiochemical Methods. Analytical Chemistry of Astatine". Analyst. 77 (920): 774–777. Bibcode:1952Ana....77..774A. doi:10.1039/AN9527700774. (subscription required)
^Cite error: The named reference MoreAtIC was invoked but never defined (see the help page).
^Milanov, M.; Doberenz, V.; Khalkin, V. A.; Marinov, A. (1984). "Chemical Properties of Positive Singly Charged Astatine Ion in Aqueous Solution". Journal of Radioanalytical and Nuclear Chemistry. 83 (2): 291–299. Bibcode:1984JRNC...83..291M. doi:10.1007/BF02037143. S2CID97361684.
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