Arsenic - the classic poison of medieval and modern poisoners
and medicine in modern sports and rehabilitation medicine
Toxic and poisonous stones and minerals

Arsenic(lat. Arsenicum), As, chemical element of group V of the periodic system of Mendeleev, atomic number 33, atomic mass 74.9216; steel gray crystals. The element consists of one stable isotope, 75 As. Poisonous in any form, medicine.

Historical reference.

Natural compounds of arsenic with sulfur (orpiment As 2 S 3, realgar As 4 S 4) were known to the peoples of the ancient world, who used these minerals as medicines and paints. The product of burning arsenic sulfides was also known - arsenic (III) oxide As 2 O 3 (“white arsenic”).

The name arsenikon is found already at the beginning of our era; it is derived from the Greek arsen - strong, courageous and served to designate arsenic compounds (based on their effect on the body). The Russian name is believed to come from “mysh” (“death” - after the use of arsenic preparations to kill yaks, as well as exterminate mice and rats). The chemical preparation of free arsenic is attributed to 1250 AD. In 1789, A. Lavoisier included arsenic in the list of chemical elements.

Arsenic. Belorechenskoye deposit, North. Caucasus, Russia. ~10x7 cm. Photo: A.A. Evseev.

Distribution of arsenic in nature.

The average arsenic content in the earth's crust (clarke) is 1.7 * 10 -4% (by mass), in such quantities it is present in most igneous rocks. Since arsenic compounds are volatile at high temperatures (dry volcanic sublimation on batholiths), the element sublimes into the atmosphere and air in the form of metal vapors (mirages - the air below ripples) does not accumulate during magmatic lava processes sublimating through cracks and tubes; it is concentrated, deposited from vapors and hot deep waters on crystal formation catalysts - metallic iron (together with S, Se, Sb, Fe, Co, Ni, Cu and other elements).

During volcanic eruptions (during dry sublimation of arsenic), arsenic in the form of its volatile compounds enters the atmosphere. Since arsenic is multivalent, its migration is influenced by the redox environment. Under oxidizing conditions of the earth's surface, arsenates (As 5+) and arsenites (As 3+) are formed.

These are rare minerals found in areas of arsenic deposits. Native arsenic and As 2+ minerals are even less common. Of the minerals and arsenic compounds (about 180), arsenopyrite FeAsS is of industrial importance (the iron atom is the center of pyrite formation, the formula of the starting "single crystal" is Fe + (As + S)).

Arsenopyrite vein. Trifonovskaya mine, Kochkarskoe deposit (Au), Plast, South Ural, Russia. Arsenics. Photo: A.A. Evseev.

Small amounts of arsenic are essential for life. However, in areas of arsenic deposits and the activity of young volcanoes, soils in places contain up to 1% arsenic, which is associated with livestock diseases and the death of vegetation. The accumulation of arsenic is especially characteristic of the landscapes of steppes and deserts, in the soils of which arsenic is inactive. In humid climates and when plants and soils are watered, arsenic is washed out of the soil.

In living matter there is an average of 3·10 -5% arsenic, in rivers 3·10 -7%. Arsenic carried by rivers into the ocean precipitates relatively quickly. In sea water, 1 * 10 -7% arsenic (there is a lot of gold that displaces it), but in clays and arsenic shales (along the banks of rivers and reservoirs, in clay black formations and along the edges of quarries) - 6.6 * 10 - 4 %. Sedimentary iron ores, ferromanganese and other iron nodules are often enriched in arsenic.

Physical properties of arsenic.

Arsenic has several allotropic modifications. Under normal conditions, the most stable is the so-called metallic, or gray, arsenic (α-As) - gray steel fragile crystalline mass (according to properties - like pyrite, gold blende, iron pyrite); on a fresh fracture it has a metallic luster, it quickly tarnishes in air, as it is covered with a thin film of As 2 O 3 .

Arsenic is rarely called silver blende - the case of the Tsar's Clerks A.M. Romanov in the middle of the 17th century, "silver", not malleable, sometimes in powder, can be ground - poison for the Tsar of All Rus'. The most famous Spanish scandal in the tavern of poisoners near the Don Quixote mill on the way to Almaden, Spain, where red cinnabar is mined on the European continent (scandals about the sale of virgins in the Krasnodar Territory of the Russian Federation, the village of Novy, crystal red cinnabar, do not want to work) .

Arsenopyrite. Druze of prismatic crystals with calcite spherulites. Freiberg, Saxony, Germany. Photo: A.A. Evseev.

The crystal lattice of gray arsenic is rhombohedral (a = 4.123Å, angle α = 54 o 10", x = 0.226), layered. Density 5.72 g/cm 3 (at 20 o C), electrical resistivity 35 * 10 -8 ohm *m, or 35*10 -6 ohm*cm, temperature coefficient of electrical resistance 3.9·10 -3 (0 o -100 o C), Brinell hardness 1470 MN/m 2, or 147 kgf/mm 2 (3- 4 according to Moocy); arsenic is diamagnetic.

Under atmospheric pressure, arsenic sublimes at 615 o C without melting, since the triple point of α-As lies at 816 o C and a pressure of 36 at.

Arsenic vapor consists of As 4 molecules up to 800 o C, above 1700 o C - only As 2. When arsenic vapor condenses on a surface cooled by liquid air, yellow arsenic is formed - transparent, wax-soft crystals with a density of 1.97 g/cm 3, similar in properties to white phosphorus.

When exposed to light or low heat, it turns into gray arsenic. Glassy-amorphous modifications are known: black arsenic and brown arsenic, which, when heated above 270 o C, turn into gray arsenic

Chemical properties of arsenic.

The configuration of the outer electrons of the arsenic atom is 3d 10 4s 2 4p 3. In compounds, arsenic has oxidation states +5, +3 and -3. Gray arsenic is less chemically active than phosphorus. When heated in air above 400 o C, arsenic burns, forming As 2 O 3.

Arsenic combines directly with halogens; under normal conditions, AsF 5 is a gas; AsF 3 , AsCl 3 , AsBr 3 - colorless volatile liquids; AsI 3 and As 2 I 4 are red crystals. When arsenic is heated with sulfur, sulfides are obtained: orange-red As 4 S 4 and lemon-yellow As 2 S 3.

Pale yellow silver sulfide As 2 S 5 ( arsenopyrite) is deposited by passing H 2 S into an ice-cooled solution of arsenic acid (or its salts) in fuming hydrochloric acid: 2H 3 AsO 4 + 5H 2 S = As 2 S 5 + 8H 2 O; At about 500 o C it decomposes into As 2 S 3 and sulfur.

All arsenic sulfides are insoluble in water and dilute acids. Strong oxidizing agents (mixtures of HNO 3 + HCl, HCl + KClO 3) convert them into a mixture of H 3 AsO 4 and H 2 SO 4.

As 2 S 3 sulfide easily dissolves in sulfides and polysulfides of ammonium and alkali metals, forming salts of acids - thioarsenic H 3 AsS 3 and thioarsenic H 3 AsS 4 .

With oxygen, arsenic produces oxides: arsenic oxide (III) As 2 O 3 - arsenous anhydride and arsenic oxide (V) As 2 O 5 - arsenic anhydride. The first of them is formed by the action of oxygen on arsenic or its sulfides, for example 2As 2 S 3 + 9O 2 = 2As 2 O 3 + 6SO 2.

As 2 O 3 vapors condense into a colorless glassy mass, which becomes opaque over time due to the formation of small cubic crystals, density 3.865 g/cm 3 . The vapor density corresponds to the formula As 4 O 6; above 1800 o C the steam consists of As 2 O 3.

2.1 g of As 2 O 3 dissolves in 100 g of water (at 25 o C). Arsenic (III) oxide is an amphoteric compound with a predominance of acidic properties. Salts (arsenites) corresponding to orthoarsenic acids H 3 AsO 3 and metaarsenic HAsO 2 are known; the acids themselves have not been obtained. Only alkali metal and ammonium arsenites are soluble in water.

As 2 O 3 and arsenites are usually reducing agents (for example, As 2 O 3 + 2I 2 + 5H 2 O = 4HI + 2H 3 AsO 4), but can also be oxidizing agents (for example, As 2 O 3 + 3C = 2As + 3CO ).

Arsenic (V) oxide is prepared by heating arsenic acid H 3 AsO 4 (about 200 o C). It is colorless, at about 500 o C it decomposes into As 2 O 3 and O 2. Arsenic acid is obtained by the action of concentrated HNO 3 on As or As 2 O 3.

Arsenic acid salts (arsenates) are insoluble in water, with the exception of alkali metal and ammonium salts. Salts are known that correspond to the acids orthoarsenic H 3 AsO 4 , metaarsenic HAsO 3 and pyroarsenic H 4 As 2 O 7 ; the last two acids were not obtained in a free state. When alloyed with metals, arsenic mostly forms compounds (arsenides).

Obtaining arsenic.

Arsenic is produced industrially by heating arsenic pyrites:

FeAsS = FeS + As

or (less often) reduction of As 2 O 3 with coal. Both processes are carried out in retorts made of refractory clay connected to a receiver for condensing arsenic vapor.

Arsenic anhydride is obtained by oxidative roasting of arsenic ores or as a by-product of roasting polymetallic ores, which almost always contain arsenic. During oxidative roasting, As 2 O 3 vapors are formed, which condense in the collection chambers.

Crude As 2 O 3 is purified by sublimation at 500-600 o C. Purified As 2 O 3 is used for the production of arsenic and its preparations.

Use of arsenic.

Small additions of arsenic (0.2-1.0% by weight) are introduced into lead used for the production of gun shot (arsenic increases the surface tension of molten lead, due to which the shot takes on a shape close to spherical; arsenic slightly increases the hardness of lead). As a partial substitute for antimony, arsenic is included in some babbitt and printing alloys.

Pure arsenic is not poisonous, but all its compounds that are soluble in water or can go into solution under the influence of gastric juice are extremely poisonous; Arsenic hydrogen is especially dangerous. Of the arsenic compounds used in production, arsenic anhydride is the most toxic.

Almost all sulfide ores of non-ferrous metals, as well as iron (sulfur) pyrite, contain an admixture of arsenic. Therefore, during their oxidative roasting, along with sulfur dioxide SO 2, As 2 O 3 is always formed; Most of it condenses in the smoke channels, but in the absence or low efficiency of treatment facilities, the exhaust gases of ore kilns carry away noticeable amounts of As 2 O 3.

Pure arsenic, although not poisonous, is always covered with a coating of toxic As 2 O 3 when stored in air. In the absence of properly performed ventilation, etching of metals (iron, zinc) with industrial sulfuric or hydrochloric acids containing arsenic is extremely dangerous, since this produces arsenic hydrogen.

Arsenic in the body.

As a trace element, arsenic is ubiquitous in living nature. The average arsenic content in soils is 4*10 -4%, in plant ash - 3*10 -5%. The arsenic content in marine organisms is higher than in terrestrial organisms (in fish 0.6-4.7 mg per 1 kg of raw material, accumulates in the liver).

The largest amount of it (per 1 g of tissue) is found in the kidneys and liver (when ingested, it does not accumulate in the brain). A lot of arsenic is found in the lungs and spleen, skin and hair; relatively little - in the cerebrospinal fluid, brain (mainly in the pituitary gland), gonads and others.

In tissues, arsenic is found mainly protein fraction(“the stone of bodybuilders and athletes”), much less - in the acid-soluble and only a small part of it is found in the lipid fraction. It is used to treat progressive muscular dystrophy - it does not accumulate in the brain and bones (sports doping, treated for hostages and prisoners of concentration camps such as "Auschwitz" in Poland, EU, 1941-1944).

Arsenic is involved in redox reactions: oxidative breakdown of complex biological carbohydrates and sugars, fermentation, glycolysis, etc. Improves mental abilities (contributes to the process of breaking down sugars in the brain). Arsenic compounds are used in biochemistry as specific enzyme inhibitors for studying metabolic reactions. Promotes the breakdown of biological tissues (accelerates). It is actively used in dentistry and oncology - to eliminate rapidly growing and early aging cancer cells and tumors.

Mixture (hard sulfide alloy) of thallium, arsenic and lead: Hutchinsonite (Hutchinsonite)

Mineral formula (Pb, Tl)S` Ag2S * 5 As2 S5 is a complex sulfide and adsenide carbide salt. Rhombus. The crystals are prismatic to needle-shaped. Cleavage perfect according to (010). The aggregates are radial-needle-shaped, granular. Hardness 1.5-2. Specific gravity 4.6. Red. Diamond shine. In hydrothermal deposits with dolomite, with sulfides and arsenides of Zn, Fe, As and sulfoarsenides. The result of dry sulfuric and arsenic sublimation of magma through calderas and open volcanic vents, as well as dry sublimation through cracks in deep igneous plutonites from the hot magma of the Earth. Contains silver. It is one of the ten very dangerous to human and animal health and carcinogenic stones and minerals that crystallize in modern conditions among other rocks in the form of harmful, hazardous to health (if handled without permission) and deceptive ore beauty. In the photo - Hutchinsonite with orpiment.

Poisonous minerals. Hutchinsonite - named after the mineralogist Hutchinson from the University of Cambridge and resembles lead in appearance (it can be used for protection against radiation). Opened in 1861. A deadly mixture (hard alloy) of thallium, arsenic and lead. Contact with this mineral can lead to hair loss (alopecia, baldness, baldness), complex skin diseases and death. All of its main components are poisonous. Very similar to lead, native silver, pyrite ("dry pyrite") and arsenopyrite. It is also similar to stibnite (an antimony compound, also very poisonous). Also similar to zeolites. Hutchinsonite is a dangerous and striking carbide mixture of thallium, lead and arsenic. Three rare, very expensive and valuable ore metals form a toxic, lethal cocktail of minerals that must be handled with the utmost care. Affects the brain, heart and liver simultaneously.

Thallium is lead's dark counterpart. This dense, fatty metal is similar in atomic mass to lead, but is even more deadly. Thallium is a rare metal that appears in highly toxic compounds consisting of strange combinations of elements (hard alloys). The effects of thallium exposure are more dangerous than lead, and include hair loss (alopecia, baldness), serious illness from skin contact, and in many cases death. Hutchinsonite was named after John Hutchinson, a famous mineralogist at the University of Cambridge. This mineral can be found in mountainous regions of Europe, most often in ore deposits. A mineral popular in medical dentistry, etc. Alcoholics are afraid of the mineral.

Hutchinsonite (Hutchinsonite) is sometimes jokingly called “dry” or “solid alcohol”, “solid alcohol” (and not only for the harmful effects of intoxicating poisoning on the body and human health). The chemical formula of food alcohol (alcohol) is C2 H5 (OH). Hutchinsonite (Hutchinsonite) has a chemical formula - 5 As2 S5 * (Pb, Tl) S` Ag2 S or 5 As2 S5 * (Pb, Tl) S` Ag Ag S. The formula of Hutchinsonite (Hutchinsonite) is sometimes rewritten differently - As2 S5 * ( Pb) + As2 S5 * (Tl) + As2 S5 * S + As2 S5 * Ag + As2 S5 * AgS. Chemical separation of components in production is also carried out according to the type of different alcohols (layers of mechanical enrichment, different in mass and weight, which are crushed by ultrasound and separated in a centrifuge or on a vibration platform - the horror movie "Aliens"). Other similar variations of the chemical formula are possible (composition varies).

ADR 6.1
Toxic substances (poison)
Risk of poisoning through inhalation, skin contact or ingestion. Hazardous to the aquatic environment or sewerage system
Use a mask when leaving a vehicle in an emergency

ADR 3
Flammable liquids
Fire risk. Risk of explosion. Containers may explode when heated (super hazardous - easy to burn)

ADR 2.1
flammable gases
Fire risk. Risk of explosion. May be under pressure. Risk of suffocation. May cause burns and/or frostbite. Containers can explode when heated (extremely dangerous - practically do not burn)
Use cover. Avoid low surface areas (holes, lowlands, trenches)
Red diamond, ADR number, black or white flame

ADR 2.2
gas cylinder Non-flammable, non-toxic gases.
Risk of suffocation. May be under pressure. They can cause frostbite (similar to a burn - pallor, blisters, black gas gangrene - creaking). Containers can explode when heated (extremely dangerous - explosion from a spark, flame, match, practically do not burn)
Use cover. Avoid low surface areas (holes, lowlands, trenches)
Green diamond, ADR number, black or white gas cylinder (cylinder, thermos type)

ADR 2.3
Toxic gases. Skull and crossbones
Danger of poisoning. May be under pressure. May cause burns and/or frostbite. Containers can explode when heated (extremely dangerous - instantaneous spread of gases throughout the surrounding area)
Use a mask when leaving a vehicle in an emergency. Use cover. Avoid low surface areas (holes, lowlands, trenches)
White diamond, ADR number, black skull and crossbones

Name of particularly dangerous cargo during transportation	Number UN	Class ADR
Arsenic (III) oxide ARSENE TRIOXIDE	1561	6.1
	1685	6.1
	1557	6.1
	1561	6.1
Calcium arsenic acid ARSENATE COMPOUND, SOLID, N.Z.K. inorganic including: Arsenati, n.c.c., Arsenite, n.c.c., Arsene sulfides, n.c.c.	1557	6.1
Calcium arsenate CALCIUM ARSENATE	1573	6.1
CALCIUM ARSENATE	1573	6.1
CALCIUM ARSENATE AND CALCIUM ARSENITE MIXTURE, SOLID	1574	6.1
Calcium arsenite	1557	6.1
AMMONIUM ARSENATE	1546	6.1
Arsenic anhydride ARSENE TRIOXIDE	1561	6.1
ARSEN	1558	6.1
ARSENIC DUST	1562	6.1
Hydrogen arsene Arsine	2188	2
Arsene-soda solution	1556	6.1
ARSENE BROMIDE	1555	6.1
ARSENE PENTOOXIDE	1559	6.1
ARSEN COMPOUND, LIQUID, N.Z.K. inorganic, including: Arsenati, n.c.c., Arsenite, n.c.c., but Arsene sulfides, n.c.c.	1556	6.1
ARSENE COMPOUND, SOLID, N.C.K. inorganic, including: Arsenati, n.c.c., Arsenite, n.c.c., but Arsene sulfides, n.c.c.	1557	6.1
ARSENE TRIOXIDE	1561	6.1
ARSENE TRICHLORIDE	1560	6.1
ARSINE	2188	2
IRON(II) ARSENATE	1608	6.1
IRON(III) ARSENATE	1606	6.1
IRON(III) ARSENITE	1607	6.1
POTASSIUM ARSENATE	1677	6.1
POTASSIUM ARSENITE	1678	6.1
ARSENIC ACID, SOLID	1554	6.1
ARSENIC ACID, LIQUID	1553	6.1
MAGNESIUM ARSENATE	1622	6.1
COPPER ARSENITE	1586	6.1
COPPER ACETOARSENITE	1585	6.1
Sodium arsenic acid SODIUM ARSENITE SOLID	2027	6.1
Sodium arsenic acid SODIUM ARSENATE	1685	6.1
SODIUM AZIDE	1687	6.1
SODIUM ARSENATE	1685	6.1
SODIUM ARSENITE SOLID	2027	6.1
SODIUM ARSENITE AQUEOUS SOLUTION	1686	6.1
Tin arsenide	1557	6.1
Arsenic tin Tin arsenite	1557	6.1
	2760	3
ARSENE-CONTAINING PESTICIDE LIQUID, FLAMMABLE, TOXIC with a flash point less than 23 o C	2760	3
ARSENE-CONTAINING PESTICIDE, SOLID, TOXIC	2759	6.1
ARSENE-CONTAINING PESTICIDE, LIQUID, TOXIC	2994	6.1
ARSENE-CONTAINING PESTICIDE, LIQUID, TOXIC, FLAMMABLE, with a flash point of at least 23 o C	2993	6.1
MERCURY (II) ARSENATE	1623	6.1
LEAD ARSENATHI	1617	6.1
LEAD ARSENITE	1618	6.1
ARSENE-ORGANIC COMPOUND, LIQUID, N.Z.K.	3280	6.1
ARSENE-ORGANIC COMPOUND, SOLID, N.Z.K.*	3465	6.1
SILVER ARSENITE	1683	6.1
STRONTIUM ARSENITE	1691	6.1
ZINC ARSENATE, ZINC ARSENITE or ZINC ARSENATE AND ZINC ARSENITE MIXTURE	1712	6.1

Some who died from cholera in the Middle Ages did not die from it. Symptoms of the disease are similar to those arsenic poisoning.

Having realized this, medieval businessmen began to offer the trioxide of the element as a poison. Substance. The lethal dose is only 60 grams.

They were divided into portions, given over several weeks. As a result, no one suspected that the man did not die from cholera.

Arsenic taste is not felt in small doses, being, for example, in food or drinks. In modern realities, of course, there is no cholera.

People don't have to worry about arsenic. Rather, it is the mice who need to be afraid. A toxic substance is a type of poison for rodents.

By the way, the element is named in their honor. The word “arsenic” exists only in Russian-speaking countries. The official name of the substance is arsenicum.

Designation in – As. The serial number is 33. Based on it, we can assume a complete list of the properties of arsenic. But let's not assume. We'll look into the issue for sure.

Properties of arsenic

The Latin name of the element translates as “strong”. Apparently, this refers to the effect of the substance on the body.

When intoxicated, vomiting begins, digestion is upset, the stomach turns, and the functioning of the nervous system is partially blocked. not one of the weak.

Poisoning occurs from any of the allotropic forms of the substance. Alltropy is the existence of manifestations of the same thing that are different in structure and properties. element. Arsenic most stable in metal form.

Steel-gray rhombohedral ones are fragile. The units have a characteristic metallic appearance, but upon contact with moist air they become dull.

Arsenic - metal, whose density is almost 6 grams per cubic centimeter. The remaining forms of the element have a lower indicator.

In second place is amorphous arsenic. Element characteristics: - almost black color.

The density of this form is 4.7 grams per cubic centimeter. Externally, the material resembles.

The usual state of arsenic for ordinary people is yellow. Cubic crystallization is unstable and becomes amorphous when heated to 280 degrees Celsius, or under the influence of simple light.

Therefore, yellow ones are soft, like in the dark. Despite the color, the aggregates are transparent.

From a number of modifications of the element it is clear that it is only half a metal. The obvious answer to the question is: “ Arsenic is a metal or non-metal", No.

Chemical reactions serve as confirmation. The 33rd element is acid-forming. However, being in acid itself does not give.

Metals do things differently. In the case of arsenic, they do not work out even upon contact with one of the strongest.

Salt-like compounds are “born” during the reactions of arsenic with active metals.

This refers to oxidizing agents. The 33rd substance interacts only with them. If the partner does not have pronounced oxidizing properties, the interaction will not take place.

This even applies to alkalis. That is, arsenic is a chemical element quite inert. How then can you get it if the list of reactions is very limited?

Arsenic mining

Arsenic is mined as a by-product of other metals. They are separated, leaving the 33rd substance.

In nature there are compounds of arsenic with other elements. It is from them that the 33rd metal is extracted.

The process is profitable, because together with arsenic there are often , , and .

It is found in granular masses or cubic crystals of tin color. Sometimes there is a yellow tint.

Arsenic compound And metal Ferrum has a “brother”, in which instead of the 33rd substance there is . This is an ordinary pyrite with a golden color.

The aggregates are similar to the arsenic version, but cannot serve as arsenic ore, although they also contain arsenic as an impurity.

Arsenic, by the way, also happens in ordinary water, but, again, as an impurity.

The amount of element per ton is so small, but even by-product mining makes no sense.

If the world's arsenic reserves were evenly distributed in the earth's crust, it would be only 5 grams per ton.

So, the element is not common; its quantity is comparable to , , .

If you look at the metals with which arsenic forms minerals, then this is not only with cobalt and nickel.

The total number of minerals of the 33rd element reaches 200. A native form of the substance is also found.

Its presence is explained by the chemical inertness of arsenic. Formed next to elements with which reactions are not provided, the hero remains in splendid isolation.

In this case, needle-shaped or cubic aggregates are often obtained. Usually, they grow together.

Use of arsenic

The element arsenic belongs to dual, not only exhibiting properties of both metal and non-metal.

The perception of the element by humanity is also dual. In Europe, the 33rd substance has always been considered a poison.

In 1733, they even issued a decree prohibiting the sale and purchase of arsenic.

In Asia, the "poison" has been used by physicians for 2000 years in the treatment of psoriasis and syphilis.

Modern doctors have proven that the 33rd element attacks proteins that provoke oncology.

In the 20th century, some European doctors also sided with the Asians. In 1906, for example, Western pharmacists invented the drug salvarsan.

It became the first in official medicine and was used against a number of infectious diseases.

True, immunity to the drug, like any constant intake of arsenic in small doses, is developed.

1-2 courses of the drug are effective. If immunity has developed, people can take a lethal dose of the element and remain alive.

In addition to doctors, metallurgists became interested in the 33rd element and began adding it to produce shot.

It is made on the basis which is included in heavy metals. Arsenic increases the lead and allows its splashes to take a spherical shape when casting. It is correct, which improves the quality of the fraction.

Arsenic can also be found in thermometers, or rather in them. It is called Viennese, mixed with the oxide of the 33rd substance.

The compound serves as a clarifier. Arsenic was also used by glassblowers of antiquity, but as a matting additive.

Glass becomes opaque when there is a significant admixture of a toxic element.

Observing the proportions, many glassblowers fell ill and died prematurely.

And tannery specialists use sulfides arsenic.

Element main subgroups Group 5 of the periodic table is included in some paints. In the leather industry, arsenicum helps to remove hair from.

Arsenic price

Pure arsenic is most often offered in metallic form. Prices are set per kilogram, or ton.

1000 grams costs about 70 rubles. For metallurgists, they offer ready-made, for example, arsenic with copper.

In this case, they take 1500-1900 rubles per kilo. Kilograms sell and arsenic anhydrite.

It is used as a skin medicine. The agent is necrotic, that is, it numbs the affected area, killing not only the causative agent of the disease, but also the cells themselves. The method is radical, but effective.

Arsenic is a non-metal and forms compounds similar in its chemical properties. However, along with non-metallic properties, arsenic also exhibits metallic ones. In air, under normal conditions, arsenic slightly oxidizes from the surface. Arsenic and its analogues are insoluble neither in water nor in organic solvents.

Arsenic is chemically active. In air at normal temperatures, even compact (fused) metallic arsenic is easily oxidized; when heated, powdered arsenic ignites and burns with a blue flame to form As 2 O 3 oxide. Also known thermally less stable non-volatile oxide As 2 O 5 .

When heated (in the absence of air), As sublimes (sublimation temperature 615 o C). The steam consists of As 4 molecules with an insignificant (about 0.03%) admixture of As 2 molecules.

Arsenic belongs to the group of oxidizing-reducing elements. When exposed to strong reducing agents, it exhibits oxidizing properties. Thus, under the action of metals and hydrogen at the moment of release, it is capable of producing the corresponding metal and hydrogen compounds:

6Ca +As 4 = 2Ca 3 As 2

Under the influence of strong oxidizing agents, arsenic transforms into a tri- or pentavalent state. For example, when heated in air, arsenic, oxidized by oxygen, burns and forms white smoke - arsenic (III) oxide As 2 O 3:

As 4 + 3O 2 =2As 2 O 3

Stable forms of arsenic oxide in the gas phase are sesquioxide (arsenic anhydride) As 2 O 3 and its dimer As 4 O 6. Up to 300 o C, the main form in the gas phase is a dimer; above this temperature it is noticeably dissociated, and at temperatures above 1800 o C the gaseous oxide consists practically of monomeric As 2 O 3 molecules.

A gaseous mixture of As 4 O 6 and As 2 O 3 is formed during the combustion of As in oxygen, during the oxidative roasting of As sulfide minerals, such as arsenopyrite, non-ferrous metal ores and polymer ores.

When As 2 O 3 (As 4 O 6) vapor condenses above 310 o C, the glassy form of As 2 O 3 is formed. When steam condenses below 310 o C, a colorless polycrystalline cubic modification of arsenolite is formed. All forms of As 2 O 3 are highly soluble in acids and alkalis.

As(V) oxide (arsenic anhydride) As 2 O 5 – colorless crystals of the orthorhombic system. When heated, As 2 O 5 dissociates into As 4 O 6 (gas) and O 2 . As 2 O 5 is obtained by dehydrating concentrated solutions of H 3 AsO 4 followed by calcination of the resulting hydrates.

The oxide As 2 O 4 is known, obtained by sintering As 2 O 3 and As 2 O 5 at 280 o C in the presence of water vapor. Gaseous AsO monoxide is also known, which is formed during an electrical discharge in As trioxide vapor at reduced pressure.

When dissolved in water, As 2 O 5 forms orthoarsenic H 3 AsO 3 , or As(OH) 3 , and metaarsenic HAsO 2 , or AsO(OH), which exist only in solution and have amphoteric, predominantly acidic, properties.

In relation to acids, arsenic behaves as follows:

— arsenic does not react with hydrochloric acid, but in the presence of oxygen arsenic trichloride AsCl 3 is formed:

4As +3O 2 +12HCl = 4AsCl 3 +6H 2 O

- dilute nitric acid, when heated, oxidizes arsenic to orthoarsenic acid H 3 AsO 3 , and concentrated nitric acid – to orthoarsenic acid H 3 AsO 4:

3As + 5HNO 3 + 2H 2 O = 3H 2 AsO 4 +5NO

Orthoarsenic acid(arsenic acid) H 3 AsO 4 *0.5H 2 O – colorless crystals; melting point – 36 o C (with decomposition); soluble in water (88% by weight at 20 o C); hygroscopic; in aqueous solutions – tribasic acid; when heated to about 100 o C, it loses water, turning into pyroarsenic acid H 4 As 5 O 7, at higher temperatures it turns into metaarsenic acid HAsO 3. Obtained by oxidation of As or As 2 O 3 with concentrated HNO 3 . It is easily soluble in water and is approximately equal in strength to phosphorus.

The oxidizing properties of arsenic acid are noticeable only in an acidic environment. Arsenic acid is capable of oxidizing HI to I 2 by reversible reactions:

H 3 AsO 4 + 2HI = H 3 AsO 3 + I 2 + H 2 O

Orthoarsenical acid (arsenous acid) H 3 AsO 3 exists only in aqueous solution; weak acid; obtained by dissolving As 2 O 3 in water; intermediate product in the preparation of arsenites (III) and other compounds.

- concentrated sulfuric acid reacts with arsenic according to the following equation to form orthoarsenic acids:

2As + 3H 2 SO 4 = 2H 3 AsO 3 +3SO 2

- alkali solutions do not react with arsenic in the absence of oxygen. When arsenic is boiled with alkalis, it is oxidized into the arsenic acid salt H 3 AsO 3 . When fused with alkalis, arsine (arsenous hydrogen) AsH 3 and arsenates (III) are formed. Apply AsH 3

for doping semiconductor materials with arsenic to obtain high purity As.

Unstable higher arsines are known: diarsine As 2 H 4, decomposes already at -100 o C; triarsine As 3 H 5 .

Metallic arsenic easily reacts with halogens, giving volatile halides AsHal 3:

As +3Cl 2 = 2AsCl 3

AsCl 3 is a colorless oily liquid that fumes in air and, when solidified, forms crystals with a pearlescent sheen.

C F 2 also forms AsF 5 - pentafluoride - a colorless gas, soluble in water and alkali solutions (with a small amount of heat), in diethyl ether, ethanol and benzene.

Powdered arsenic spontaneously ignites in an environment of F 2 and Cl 2 .

With S, Se and Te, arsenic forms the corresponding chalcogenides:

sulfides - As 2 S 5, As 2 S 3 (orpiment mineral in nature), As 4 S 4 (realgar mineral) and As 4 S 3 (dimorphite mineral); selenides – As 2 Se 3 and As 4 Se 4; telluride – As 2 Te 3 . Arsenic chalcogenides are stable in air, insoluble in water, highly soluble in alkali solutions, and when heated - in HNO 3. They have semiconductor properties and are transparent in the IR region of the spectrum.

With most metals it gives metallic compounds - arsenides. Gallium arsenide and indium arsenide– important semiconductor compounds.

There are numerous known arsenicorganic connections. Organoarsenic compounds contain an As-C bond. Sometimes organoarsenic compounds include all organic compounds containing As, for example, esters of arsenic acid (RO) 3 As and arsenic acid (RO) 3 AsO. The most numerous group of organoarsenic compounds are As derivatives with a coordination number of 3. This includes organoarsines R n AsH 3-n, tetraorganodiarsines R 2 As-AsR 2, cyclic and linear polyarganoarsines (RAs) n, as well as organoarsonic and diarganoarsinous acids and their derivatives R n AsX 3-n (X= OH, SH, Hal, OR', NR 2', etc.). Most organoarsenic compounds are liquids, polyorganoarsines and organic acids As are solids, CH 3 AsH 2 and CF 3 AsH 2 are gases. These compounds, as a rule, are soluble in organic solvents, limitedly soluble in water, and relatively stable in the absence of oxygen and moisture. Some tetraorganodiarsines are flammable in air.

Arsenic (the name comes from the word mouse, used to bait mice) is the thirty-third element of the periodic table. Refers to semimetals. When combined with an acid, it does not form salts, being an acid-forming substance. Can form allotropic modifications. Arsenic has three currently known crystal lattice structures. Yellow arsenic exhibits the properties of a typical non-metal, amorphous arsenic is black, and the most stable metallic arsenic is gray. In nature, it is most often found in the form of compounds, less often in a free state. The most common are compounds of arsenic with metals (arsenides), such as arsenic iron (arsenopyrite, poisonous pyrite), nickel (kupfernickel, so named because of its similarity to copper ore). Arsenic is a low-active element, insoluble in water, and its compounds are classified as slightly soluble substances. Arsenic oxidation occurs during heating; at room temperature this reaction proceeds very slowly.

All arsenic compounds are very strong toxins that have a negative effect not only on the gastrointestinal tract, but also on the nervous system. History knows many sensational cases of poisoning with arsenic and its derivatives. Arsenic compounds were used as poison not only in medieval France, they were known even in ancient Rome and Greece. The popularity of arsenic as a potent poison is explained by the fact that it is almost impossible to detect it in food; it has neither smell nor taste. When heated, it turns into arsenic oxide. Diagnosing arsenic poisoning is quite difficult, since it has similar symptoms to various diseases. Most often, arsenic poisoning is confused with cholera.

Where is arsenic used?

Despite their toxicity, arsenic derivatives are used not only for baiting mice and rats. Since pure arsenic has high electrical conductivity, it is used as a dopant that imparts the required type of conductivity to semiconductors such as germanium and silicon. In non-ferrous metallurgy, arsenic is used as an additive, which gives alloys strength, hardness and corrosion resistance in a gaseous environment. In glassmaking, it is added in small quantities to brighten glass; in addition, it is part of the famous “Vienna glass”. Nickelin is used to color glass green. In the tanning industry, arsenic sulfate compounds are used when processing hides to remove hairs. Arsenic is part of varnishes and paints. In the woodworking industry, arsenic is used as an antiseptic. In pyrotechnics, “Greek fire” is made from arsenic sulfide compounds and used in the production of matches. Some arsenic compounds are used as chemical warfare agents. The toxic properties of arsenic are used in dental practice to kill dental pulp. In medicine, arsenic preparations are used as a medicine that increases the overall tone of the body, to stimulate an increase in the number of red blood cells. Arsenic has an inhibitory effect on the formation of leukocytes, so it is used in the treatment of some forms of leukemia. A huge number of medical preparations are known that are based on arsenic, but recently they have been gradually replaced by less toxic drugs.

Despite its toxicity, arsenic is one of the most essential elements. When working with its connections, you must adhere to safety rules, which will help avoid undesirable consequences.

Physical properties
The atomic number of arsenic is 33, the atomic mass is 74.91. Arsenic can exist in three modifications:
1) metallic - crystalline modification from silver-gray to black. This modification of arsenic, crystallizing in a rhombohedral form, is formed by cooling arsenic vapor from a gas mixture superheated to a very high temperature;
2) amorphous - black-brown or gray, which is formed when arsenic vapor, superheated to a very high temperature, is deposited (cooled) on a plate heated to the temperature of arsenic evaporation;
3) yellow arsenic, crystallizing in the cubic system and depositing during sublimation in hydrogen. Yellow arsenic is the least stable modification; it turns into amorphous black arsenic when heated to 270-280 ° C or at ordinary temperature under the influence of light.
All three modifications of arsenic are different in their physical properties. The density of metallic arsenic is 5.73; amorphous brown 4.7; crystal yellow 2.0 g/cm3. Metallic arsenic is fragile and crumbles (breaks) on impact. The hardness of arsenic of this modification on a mineralogical scale is 3-4. Due to its high brittleness, its pressure treatment is impossible.
The melting point of arsenic lies in the range of 817-868 ° C. Significant evaporation of arsenic at atmospheric pressure begins at 554 ° C, but noticeable elasticity of arsenic vapor is observed at ordinary temperatures. Therefore, arsenic is usually stored in sealed ampoules.
In vacuum, the sublimation of arsenic begins already at 90°C.
The value of arsenic vapor pressure depending on temperature is expressed by the following figures:

Electrical Properties
The electrical resistivity of the metal modification of arsenic at 0°C is 35*10-ohm*cm. Metallic arsenic conducts electricity well, while the other two varieties are characterized by high electrical resistivity. Thus, the electrical resistivity at ordinary temperature of black (gray) amorphous arsenic is 10v11-10v12 ohm*cm, and at higher temperatures it decreases, as can be seen from the data below:

Above 250° C, the resistance of amorphous black arsenic changes significantly depending on its exposure to overheating temperature. So, for example, arsenic, heated to 260 ° C and held at this temperature for 20 minutes, has a resistance of 3400 ohm*cm, held for 70 minutes 1000 ohm*cm; 90 min 2500 ohm * cm, and aged 170 min 11 ohm * cm.
Chemical properties of arsenic and its compounds
Arsenic has a relatively low chemical activity. At ordinary temperatures in air, it oxidizes very slowly, but in crushed form, and also when heated in a compact state, it quickly burns in an air atmosphere, forming AS2O3.
Arsenic is insoluble in water; nitric acid and aqua regia oxidize it to arsenic acid. Hydrochloric acid acts on arsenic very slowly and only in the presence of air.
Arsenic and oxygen. There are two oxygen compounds of arsenic: trioxide As2O3 and pentoxide As2O5. The vapor pressure of As2O3 at 300° C is 89 mmHg. Art.
Hydrogen and carbon relatively easily reduce arsenic trioxide by the reactions:

As2O3 + 3H2 → 2As + 3H2O;
As2O3+ 3С → 2As + 3CO.

When arsenic trioxide interacts with metals when heated, arsenic is reduced and metals are oxidized, which for zinc, potassium, sodium and aluminum is accompanied by a large release of heat and light.
Arsenic pentoxide (As2O5) is reduced to As2O3 when heated with a variety of reducing agents (phosphorus, arsenic itself, carbon, antimony, bismuth, sodium, potassium, silicon, zinc, iron, copper, tin, lead, manganese, cobalt, etc.). Therefore, in the processes of producing arsenic, pentoxide plays a very insignificant role, since, once formed, it quickly turns into trioxide.
Arsenic and hydrogen. Arsenic with hydrogen forms a number of compounds: As2H2; As4H2; AsH3. When heated in a vacuum, the As2H2 compound decomposes into arsenic and hydrogen. In air, this compound is stable at ordinary temperatures, but when heated, it oxidizes vigorously.
When heated, the As4H2 compound decomposes into arsenic, hydrogen and AsH3. The compound AsH3 (arsine) is a colorless gas, very poisonous, slightly soluble in water.
This compound cannot be obtained by direct interaction of arsenic and hydrogen under ordinary conditions. Its formation requires high pressure and temperature. Arsenic hydrogen is usually produced by reacting arsenic with water vapor:

4As + 3H2O → As2O3 + 2AsH3.

The melting point of arsine is -113.5° C. The vapor pressure at 0° C is about 9 at, and at 15° C 13 at.
When AsH3 is passed over a heated metal, arsine decomposes, releasing hydrogen and forming arsenide of the corresponding metal, for example, potassium arsenide, sodium arsenide, etc.
Arsenic and phosphorus. When arsenic and phosphorus are heated together (to red heat), the compound As2P is formed. This compound is unstable - it decomposes and oxidizes in light, even under water.

Arsenic does not interact with carbon.
Arsenic halides. Arsenic reacts with halogens at ordinary temperatures. Some properties of arsenic halides are given in table. 61.
Arsenic and its compounds are highly toxic, so special safety precautions must be taken when working with them.

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