منابع مشابه
NONSTOICHIOMETRIC COMPOUNDS Nonstoichiometry in line compounds
Phases having compositional fields narrower than about 1 at.% and appearing as lines in binary phase diagrams often are assumed to have properties independent of composition. That such an assumption can be seriously in error is illustrated by recent measurements on pairs of samples prepared to have compositions at opposing phase boundaries. Two microscopic properties, lattice locations of highl...
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Selenium is a naturally occurring substance that is toxic at high concentrations but is also a nutritionally essential element. Hydrogen selenide is the most acutely toxic selenium compound. Acute (short-term) exposure to elemental selenium, hydrogen selenide, and selenium dioxide by inhalation results primarily in respiratory effects, such as irritation of the mucous membranes, pulmonary edema...
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A noun-compound is a compressed proposition that requires an audience to recover the implicit relationship between two concepts that are expressed as nouns. Listeners recover this relationship by considering the most typical relations afforded by each concept. These relational possibilities are evident at a linguistic level in the syntagmatic patterns that connect nouns to the verbal actions th...
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Chromium occurs in the environment primarily in two valence states, trivalent chromium (Cr III) and hexavalent chromium (Cr VI). Exposure may occur from natural or industrial sources of chromium. Chromium III is much less toxic than chromium (VI). The respiratory tract is also the major target organ for chromium (III) toxicity, similar to chromium (VI). Chromium (III) is an essential element in...
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Organotin compound that have at least one Sn-C bond have wide commercial applications as PVC stabilizer, antifouling agent in paint and as agrochemicals. The general formula for organotin compounds is R4SnX4 - n where R is normally alkyl or aryl groups and X=Cl-, OH-, CH3COO- . If n=3, the compound has the highest toxicity, for example Et3SnOAC has LD 50 4mg/Kg ( rats ) and this is the m...
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ژورنال
عنوان ژورنال: Nature
سال: 1967
ISSN: 0028-0836,1476-4687
DOI: 10.1038/2151523b0