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The bismuth is a chemical element of the family of the Pnictogène S, symbol Bi and Atomic number 83.

Confused a long time with the Lead or the tin, it was identified in 1753 by Claude Geoffroy the Young person who separated it from lead.

It is a metal of which all salts and the vapors are toxic, little present in the Environment (less 1µg/m3 in the rural air, approximately 1 mg/kg in the grounds, the drink water while bringing 5 to 20 µg/jour). It is famous present in very small proportion in the animal organizations, but its kinetics in the environment and the organizations was studied little contrary to that of other heavy metals. One does not know utility to him as a trace element.

It is a by-product of the extraction of lead, Cuivre, tin, money and Or. The exploitable ore resources seem limited about it.

Its name would come from German “Weisse Masse” (white mass).

Characteristics

chemical Element heavy, of mass 209, symbol Bi and Atomic number 83 pertaining to the group of the Pnictogène S.
Metal white slightly rosy, crystalline, fragile and relatively heavy: D = 9,780. it is obtained starting from its ore (Bismite).
It is metal more Diamagnétique and the worst driver of heat after the mercury.
Its Electrical resistance is very high. Moreover it strongly increases with a magnetic field (extremely Hall effect).
It is the famous least toxic being of heavy metals, or in any case that of which the effects are most quickly reversible.
bismuth has the characteristic (which it shares with the Eau) to be denser in the liquid state than in a solid state.

Liquid density: > 9,8, solid Density: 9,780 (cf above)

Toxicity for the man

Its mode of physiopathological action was studied little and is not included/understood yet, but in 1860, more than 100 years before its almost total prohibition in France (in 1974), Antoine Bechamp (Contemporary of Pasteur, Professor in Montpellier), in his Thesis of medicine ( “Preparation and characters of the bismuth subnitrate” ) in collaboration with C. Saintpierre, already warned as for the toxicity of bismuth salts.

Bismuth salts whose salicylate of bismuth were tested parentéralement with human against the Syphilis, with serious side effects related to its toxicity (Gingivostomatite with “bismuth line ” (black spots on the gums, stinking breath, salivation), damage on the Foie, the Rein, and especially effect Neurotoxique S affecting the unit of the central Nervous system. With the difference in the others Heavy metals, its toxic effects seem to disappear after a few months, but its effects on the Embryon or the Fetus do not seem to be studied, not more than its impacts on the workmen who were exposed there. Its vapors are toxic.

Antidotes : chelating, D-pénicillamine and its N-acétyl derivative are antidotes which were effective on the mouse poisoned by bismuth citrate by way intrapéritoéale. Introduced bismuth is almost not found in plasma (normally lower than 1 ron 10), which shows that it is partially absorbed by the digestive tract.

In spite of warning statements dating of more than one century, bismuth before 1974 was used with raised posology, without period of interruption, any time limit. Precautions for use enacted as of before 1910 required that because of its toxicity, bismuth be prescribed in discontinuous cures, but laboratories and doctors encouraged his therapeutic use which in 10 years (of 1964 to 1974) had doubled reaching 800 t/an in France.

Progress of epidemiology made it possible in France as of 1974 to allot in an unquestionable way to ingestion of medicamentous bismuth of encephalopathies generally occurring in 2 phases: a prodromic phase (nonspecific disorders of type Asthenia, Insomnia, Cephalgia S loss of memory) preceding an acute phase (with serious central nervous system disorders pointing out the symptoms induced by other heavy metals such as lead or mercury; Dysarthrie, Ataxia, disorders of walk, Myoclonie S, tremors, confusion, agitation, disorders of the memory, confusional state, Hallucination S, Convulsion S.
Fortunately, the interruption of the Bismuth catch was followed of a clinical improvement in a few day, with however a persistence during a few months of asthenia, of problems of memory and sleep and/or cephalgias.

After approximately thousands of located cases, in France, and others in Australia, the Ministry for Health finally prohibited bismuth in the drugs. But it is still used in certain countries, for example in the form of “under-citrate of bismuth-colloidal” (citrate (DENOL*) and complex bismuth ranitidine citrate), only authorized against the ulcer gastroduodénal where it seems enough toxic to kill the bacterium Helicobacter pylori which generally induces this type of ulcer and which is very resistant. The bismuth amounts in this drug however much weaker than those are prescribed before 1974 and each data processing run cannot today exceed a month max with between two treatments two months a minimal stop.

Uses

Fusible (electricity): One frequently uses as fusible wire a tin and bismuth alloy (40%/60%) which has a very low melting point.

Fusible (protection fire): In the installations of extinction by water spraying (often called “sprinkler”), one uses as obturator a mixture Eutectique of bismuth (50%), of Cadmium (12,5%), of lead 25%) and tin (12,5%) which melts with 47°C.

Hunting: “Leads” (or more precisely the shot) of the cartridges " without lead " , whose Buckshot S, is an alloy of lead, Antimoine and Arsenic sometimes replaced by bismuth. To put an end to the Pollution by lead and at the many intoxications of birds, bismuth (ally with tin 5%) replaces sometimes traditional “leads”. The latter are generally replaced by mild steel which can be " bismuthé" S (against oxidation), the more so as the known Bismuth resources are limited.

Glass, ceramics: The oxynitrate of bismuth, BiONO₃, is used like white pigment in glass and ceramics. Orthovanadate BiVO₄ the bismuth is used as pigment green-yellow for glass and ceramics. For enamelling, one uses bismuth borosilicate.

Pharmacy: Bismuth was formerly used in the pharmacopeia in forms varied against the ulcer gastro-duodénal and in various digestive indications: diarrhea, constipation, colites. The basic bismuth nitrate, Bi (OH) ₂NO₃ was used to coat the bandages for burn. Many other old uses were the gastric bandages, of the remedies against the Diarrhée and in Dermatologie. It was interdict in France after many serious problems of intoxication during treatment medical.

Biocide S: it was used in certain disinfecting, but like mercury, it was replaced by less toxic products and/or dégradables.

Cosmetic: in the lipsticks, one uses bismuth oxychloride (BiOCl) or bismuth oxynitrate (BiONO₃) for his pearly brightness.

Plumbing: the use of bismuth in substitution for lead for the assemblies is being studied.

Dye: In painting, the Bi₂O₃ oxide was or is used to obtain yellow. The BiOCl oxychloride gives a white pigment.

Semiconductor with properties Thermoelectric S: Bi₂Te₃

It was also used to fireproof papers or polymers, and like catalyst, of which for the vulcanization of rubber.

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