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Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 124. Not illustrated. Chapters: Chromium-45m, Chromium-59m, Chromium-42, Chromium-43, Chromium-44, Chromium-46, Chromium-47, Chromium-55, Chromium-56, Chromium-57, Chromium-58, Chromium-60, Chromium-61, Chromium-62, Chromium-63, Chromium-64, Chromium-65, Chromium-66, Chromium-67, Chromium-48, Chromium-49, Chromium-50, Chromium-51, Chromium-52, Chromium-53, Chromium-54. Excerpt: Naturally occurring chromium (Cr) is composed of three stable isotopes; Cr, Cr, and Cr with Cr being the most abundant (83.789% natural abundance). Nineteen radioisotopes have been characterized with the most stable being Cr (also naturally occurring, 4.345 %) with a half-life of (more than) 1.8x10 years, and Cr with a half-life of 27.7 days. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority of these have half-lives that are less than 1 minute. This element also has 2 meta states. Cr is the radiogenic decay product of Mn. Chromium isotopic contents are typically combined with manganese isotopic contents and have found application in isotope geology. Mn-Cr isotope ratios reinforce the evidence from Al and Pd for the early history of the solar system. Variations in Cr/Cr and Mn/Cr ratios from several meteorites indicate an initial Mn/Mn ratio that suggests Mn-Cr isotope systematics must result from in-situ decay of Mn in differentiated planetary bodies. Hence Cr provides additional evidence for nucleosynthetic processes immediately before coalescence of the solar system. The same isotope is preferentially involved in certain leaching reactions, thereby allowing its abundance in seawater sediments to be used as a proxy for atmospheric oxygen concentrations. The isotopes of chromium range in atomic weight from 43 u (Cr) to 67 u (Cr). The primary decay mode before the most abundant stable isotope, Cr, is elec...
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