Elements poisons

Antimony was known in the days of alchemy (500 BCE to 1600 ce) when it was associated with other metals and minerals such as arsenic, sulfides, and lead used as medications. It is possible that an alchemist, Basilus Valentinus (fi. 1450), knew about antimony and some of its minerals and compounds sometime around the mid-fifteenth century ce. Physicians of this period—and earlier periods—used elements such as mercury and antimony to cure diseases, although they knew that these elements were toxic in larger doses. Antimony was used to treat depression, as a laxative, and as an emetic for over two thousand years. Despite the elements poisonous nature, physicians of that early era considered both mercury and antimony good medicines. 

All Group VI elements form a hydride HjX. With the notable exception of water, they are all poisonous gases with very unpleasant smells. Table 10.2 gives some of their important physical properties. 

The element is a steel gray, very brittle, crystalline, semimetallic solid it tarnishes in air, and when heated is rapidly oxidized to arsenous oxide with the odor of garlic. Arsenic and its compounds are poisonous. 

Because of the high rate of emission of alpha particles and the element being specifically absorbed on bone the surface and collected in the liver, plutonium, as well as all of the other transuranium elements except neptunium, are radiological poisons and must be handled with very special equipment and precautions. Plutonium is a very dangerous radiological hazard. Precautions must also be taken to prevent the unintentional formulation of a critical mass. Plutonium in liquid solution is more likely to become critical than solid plutonium. The shape of the mass must also be considered where criticality is concerned. 

Fig. 1. Periodic Table showing elements of importance in biological systems principal element of bioorganic compounds essential mineral nutrients for humans and other animals 1 essential mineral nutrient for animals, probably for humans M present in body, not known to be a nutrient or toxic element M element used in medicine element generally poisonous and present in body, possibly toxic.

Arsenic. Arsenic is under consideration for inclusion as an essential element. No clear role has been estabHshed, but aresenic, long thought to be a poison, may be involved in methylation of macromolecules and as an effector of methionine metaboHsm (158,160). Most research has focused on the toxicity or pharmaceutical properties of arsenic (158). 

Arsenic vapor [12187-88-5] As, does not combine direcdy with hydrogen to form hydrides. However, arsine (arsenic hydride) [7784-42-17, AsH, a highly poisonous gas, forms if an intermetaUic compound such as AlAs is hydrolyzed or treated with HQ. Arsine may also be formed when arsenic compounds are reduced using zinc in hydrochloric acid. Heating to 250°C decomposes arsine into its elements. 

The new data obtained on the elemental content of the ash from ritual censer confirm the hypothesis, which was postulated in earlier researches, about that possibility of the human copper-poisoning during the ritual narcotic inhalations. 

Figure 8 X-ray elemental imaging in a field-emission STEM (a) EDS data of Pd /Ce /alumina catalyst particle poisoned with SO2 and (b) 128 X 128 digital STEM images formed using X-ray counts collected at each image pixel for aluminum, palladium, cerium, and sulfur. (Courtesy of North-Holland Publishers) ...

White phosphorus. This element burns in air and can produce severe thermal and chemical burns. It may reignite on drying. After washing, rapid but brief treatment with copper sulphate (to avoid systemic absorption and copper poisoning) is used to convert the phosphorus to copper phosphide which is then removed Hydrogen fluoride. This can form painful but delayed necrosis. Treat with calcium gluconate locally and monitoring of serum calcium levels, with administration of calcium where necessary... 

Poisoning of Pellistor by, e.g., silicones, halocarbons, leaded petrol Too high a sampling rate (causing cooling of the elements)... 

Hydrogen sulfide is the only thermodynamically stable sulfane it occurs widely in nature as a result of volcanic or bacterial action and is, indeed, a prime source of elemental 8 (p. 647). It has been known since earliest times and its classical chemistry has been extensively studied since the seventeenth century.H28 is a foul smelling, very poisonous gas familiar to all students of chemistry. Its smell is noticeable at 0.02 ppm but the gas tends to anaesthetize the olefactory senses and the intensity of the smell is therefore a dangerously unreliable guide to its concentration. H28 causes irritation at 5 ppm, headaches and nausea at 10 ppm and immediate paralysis and death at 100 ppm it is therefore as toxic and as dangerous as HCN. 

H2Se (like H2O and H2S) can be made by direct combination of the elements (above 350°), but H2Te and H2P0 cannot be made in this way because of their thermal instability. H2Se is a colourless, offensive-smelling poisonous gas which can be made by hydrolysis of Al2Se3, the action of dilute mineral acids on FeSe or the surface-catalysed reaction of gaseous Se and H2 ... 

Many of the fission products formed in a nuclear reactor are themselves strong neutron absorbers (i.e. poisons ) and so will stop the chain reaction before all the (and Pu which has also been formed) has been consumed. If this wastage is to be avoided the irradiated fuel elements must be removed periodically and the fission products separated from the remaining uranium and the plutonijjm. Such reprocessing is of course inherent in the operation of fast-breeder reactors, but whether or not it is used for thermal reactors depends on economic and political factors. Reprocessing is currently undertaken in the UK, France and Russia but is not considered to be economic in the USA. 

Contrary to the expectation that a sulfur-containing substituent will be a catalyst poison, a phenylthio group serves as an effective selectivity control element in TMM cycloadditions. A single regioisomer (30) was obtained from the carbonate precursor (31) in good yield. The thermodynamically more stable sulfide (32) is readily accessible from (30) via a 1,3-sulfide shift catalyzed by PhSSPh. A wide array of synthetically useful intermediates could be prepared from the sulfides (30) and (32) with simple transformations (Scheme 2.10) [20]. 

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