| 词汇 | actinium |
| 释义 | actinium noun[ U ] uk /ækˈtɪn.i.əm/ us /ækˈtɪn.i.əm/ (symbolAc) a chemical element that is a soft, silver-white metal and is radioactive: （放射性元素）锫 Researchers are testing the actinium.研究者正在测试锕。 Thorium decays into a radium isotope, and then into actinium, which has a 10-day half-life. Projected future needs for actinium and bismuth are high. Various alternative processes have been proposed for making actinium. Chemical elements alkali metal americium antimony astatine berkelium bismuth brimstone calcium fluorine germanium lithium manganese nickel plutonium quicksilver selenium silicon sodium sulphur transition metal Examples of actiniumactinium Secondary decay products of thorium include radium and actinium. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Owing to its scarcity, high price and radioactivity, actinium has no significant industrial use. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The actinide series derives its name from the group 3 element actinium. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The new name meant parent of actinium and reflected the fact that actinium is a product of radioactive decay of protactinium. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The former reaction is carried out at room temperature, by adding hydrofluoric acid to a solution containing actinium ions. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Chemically, actinium is similar to lanthanum, which is explained by their similar ionic radii and electronic structure. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Actinium is mostly present in uranium-containing, but also in other minerals, though in much smaller quantities. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. All actinides are radioactive, paramagnetic, and, with the exception of actinium, have several crystalline phases: plutonium has seven, and uranium, neptunium and californium three. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The fourth element, either actinium or lawrencium, has only radioactive isotopes. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Several isotopes of bismuth with short half-lives occur within the radioactive disintegration chains of actinium, radium, and thorium, and more have been synthesized experimentally. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. After the synthesis, actinium is separated from radium and from the products of decay and nuclear fusion, such as thorium, polonium, lead and bismuth. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Beginning with naturally occurring thorium-232, this series includes the following elements: actinium, bismuth, lead, polonium, radium, and radon. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Elements 121 and 122 should be homologs of actinium and thorium, respectively. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Actinium reacts rapidly with oxygen and moisture in air forming a white coating of actinium oxide that impedes further oxidation. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The major difficulty in separation of actinium is the similarity of its properties with those of lanthanum. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. See all examples of actinium These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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