The chalcogens ( ) are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family . It consists of elements of oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive element of polonium (Po). Chemically unstructured chemicals (Lv) are thought to be chalcogenes as well. Often, oxygen is treated separately from other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to very different chemical behavior of sulfur, selenium, tellurium, and polonium. The word "chalcogen" comes from a combination of the Greek word khalk? S (??????) which basically means copper (this term is also used for bronze/brass, any metal in poetic taste, ore or coin), and the Greek word Latinised gene , which means born or generated .
Sulfur has been known since antiquity, and oxygen is recognized as an element in the 18th century. Selenium, tellurium and polonium were discovered in the 19th century, and livermorium in 2000. All chalcogens have six valence electrons, making them short of two electrons from the outer shell. The most common oxidation states are -2, 2, 4, and 6. They have relatively low atomic radius, especially lighter ones.
Lighter Chalcogens are usually non-toxic in elemental form, and are often critical of life, whereas heavier chalcogens are usually toxic. All chalcogens have a role in biological function, either as nutrients or toxins. Lighter Chalcogens, such as oxygen and sulfur, are rarely toxic and usually help in their pure form. Selenium is an essential nutrient but is also generally toxic. Eggs often have unpleasant effects (although some organisms can use them), and polonium is always very dangerous, both in its chemical toxicity and its radioactivity.
Sulfur has more than 20 allotropes, oxygen has nine, selenium has at least five, polonium has two, and only one tellurium crystal structure so far has been found. There are many organic chalcogen compounds. Not counting oxygen, the most common organic sulfur compounds, followed by organic selenium compounds and organic tellurium compounds. This tendency also occurs with chalcogen pnictida and compounds containing chalcogen and carbon group elements.
Oxygen is generally extracted from the air and sulfur is extracted from oil and natural gas. Selenium and tellurium are produced as a by-product of copper refining. Polonium and livermorium are most widely available in particle accelerators. The main use of elemental oxygen is in the manufacture of steel. Sulfur is mostly converted to sulfuric acid, which is widely used in the chemical industry. The most common application of Selenium is glass making. Tellurium compounds are widely used in optical disks, electronic devices, and solar cells. Some applications of polonium are due to their radioactivity.
Video Chalcogen
Properties
Atom and physical
Chalcogens exhibit similar patterns in electron configurations, especially in the outer shell, where they all have the same number of valence electrons, resulting in a similar trend in chemical behavior:
All chalcogens have six valence electrons. All chalcogens are solid and stable soft and do not have good heat. Electronegativity decreases to the chalkogen with higher atomic numbers. Density, melting and boiling points, and atomic and ionic radii tend to rise toward the chalkogens with higher atomic numbers.
Isotope
Of the six known chalcogens, one (oxygen) has the same atomic number as the nuclear magic number, which means that their atomic nuclei tend to have increased stability against radioactive decay. Oxygen has three stable isotopes, and 14 stable isotopes. Sulfur has four stable isotopes, 20 radioactive, and one isomer. Selenium has six stable or nearly stable observation isotopes, 26 radioactive isotopes, and 9 isomers. The eggs have eight stable or nearly stable, 31 unstable, and 17 isomeric isotopes. Polonium has 42 isotopes, none is stable. It has 28 additional isomers. In addition to stable isotopes, some radioactive chalcogen isotopes occur in nature, either because they are decay products, such as 210 Po, since they are primordial, such as 82 Se, due to cosmic ray spallation, or through nuclear fission of uranium. The isotope Livermorium 290 to 293 has been found. The most stable livermorium isotope is 293 Lv, which has a half-life of 0.061 seconds.
Among the lighter chalcogens (oxygen and sulfur), the most neutron-poor isotopes emission of protons, the neutron-poor isotope undergoing electron capture or the decay of , the isotope rich in neutrons undergoing? - decomposes, and the rich neutron isotope with the most neutron emissions. Middle Chalcogens (selenium and tellium) have the same decay tendencies as milder chalcogens, but their isotopes do not emerge protons and some of the most starved neutron isotopes of tellurium undergo alpha decay. The isotopes of polonium tend to decay with alpha or beta decay. Isotopes with nuclear spin are more common among selenium chalcogens and tellurium than sulfur.
Allotropes
The most common oxygen allotropes are diatomic oxygen, or O 2 , reactive paramagnetic molecules that are ubiquitous for aerobic organisms and have a blue color in their liquid state. The other allotropes are O 3 , or ozone, which is the three oxygen atoms bonded together in a bent formation. There are also allotropes called tetraoxygen, or O 4 , and six allotropes of solid oxygen include "red oxygen", which has the formula O 8 .
Sulfur has more than 20 known allotropes, which are more than any other element except carbon. The most common allotropes are in the form of eight-atom rings, but other molecular allotropes containing at least two atoms or as many as 20 are known. Other important sulfur allotropes include sulfur sulfur and monoclinic sulfur. Rhombic sulfur is more stable than two allotropes. Monoclinic sulfur takes the form of a long needle and is formed when the liquid sulfur is cooled to slightly below its melting point. The atoms in liquid sulfur are generally in the form of long chains, but above 190 ° Celsius, the chain begins to break down. If the liquid sulfur above 190 Â ° Celsius is frozen very quickly, the resulting sulfur is amorphous or "plastic" sulfur. Sulfur gas is a mixture of diatomic sulfur (S 2 ) and an 8-atom ring.
Selenium has at least five known allotropes. Gray allotropes, often referred to as "metallic" allotropes, though not metals, are stable and have hexagonal crystal structures. The allotrope of soft selenium gray, with Mohs 2 hardness, and brittle. The other four allotropes of selenium are metastable. These include two red monoclinic allotropes and two amorphous allotropes, one of which is red and one of them is black. The red allotrope turns red allotrop with heat. The ashotum allotropes are made of spirals on selenium atoms, while one of the red allotropes is made of a pile of selenium rings (Se 8 ).
Telurium is not known to have allotropes, although its distinctive shape is hexagonal. Polonium has two allotropes, known as? -polonium and? -polonium. ? -polonium has a cubic crystal structure and converts to rhombohedral? -polonium at 36 Ã, Â ° C.
Chalcogens have a varying crystal structure. Oxygen crystal structure Oxygen is monoclinic, orthorhombic sulfur, selenium and tellurium have a hexagonal crystal structure, while polonium has a cubic crystal structure.
Chemistry
Oxygen, sulfur, and selenium are non-metals, and tellurium is metalloid, which means that its chemical properties are between metal and nonmetals. It is uncertain whether polonium is a metal or a metaloid. Some sources refer to polonium as metalloid, although it has some metallic properties. Also, some allotropes of selenium display characteristics of metalloid, although selenium is usually regarded as nonmetallic. Although oxygen is a chalcogen, its chemical properties are different from other chalcogens. One reason is that the heavier chalcogens have an empty d orbitals. Oxygen electronegativity is also much higher than that of other chalcogens. This makes the polarizability of oxygen electricity several times lower than that of other chalcogens.
The oxidation number of the most common chalcogen compound with a positive metal is -2. However, the chalkogenic tendency to form compounds in the -2 state decreases to the heavier chalcogens. Other oxidation numbers, such as -1 in pyrite and peroxide, do occur. The highest formal oxidation rate is 6. This oxidation number is found in sulfates, selenates, tellurates, polonates, and corresponding acids, such as sulfuric acid.
Oxygen is the most electronegative element except fluorine, and forms compounds with almost all chemical elements, including some noble gases. Typically bonds with many metals and metaloids form oxides, including iron oxide, titanium oxide, and silicon oxide. The most common oxygen is oxidation -2, and the oxidation state -1 is also relatively common. With hydrogen, it forms water and hydrogen peroxide. Organic oxygen compounds are ubiquitous in organic chemistry.
The sulfur oxidation state is -2, 2, 4, and 6. Sulfur-containing oxygen compounds often have a prefix thio - . Sulfur chemistry is similar to oxygen, in many ways. One difference is that the sulfur-sulfur double bonds are much weaker than the oxygen-oxygen double bonds, but the single-sulfur-sulfur bond is stronger than the oxygen-oxygen single bond. Organic sulfur compounds such as thiols have a strong specific odor, and some are used by some organisms.
The selenium oxidation status is -2, 4, and 6. Selenium, like most chalcogens, is bound to oxygen. There are several organic selenium compounds, such as selenoprotein. The tellurium oxidation states are -2, 2, 4, and 6. The eggs form the tellurium monoxide, the tellurium monoxide, the tellurium monoxide, and the tellurium trioxide oxides. The polonium oxidation status is 2 and 4.
There are many acids that contain chalcogens, including sulfuric acid, sulfuric acid, selenic acid, and telluric acid. All hydrogen chalcogenides are toxic except water. Oxygen ions often come in the form of oxide ions ( O 2 -
), peroxide ions ( O 2 - < in line: vertical-align: baseline "> 2 ), and the hydroxide ions ( OH < span> - ). The sulfur ions generally come in the form of sulphide ( S 2 - span> ), sulfit ( SO 2 -
3 ), sulfate ( SO 2 -
4 ), and thiosulfate ( S
2 O 2 - < br> 3 ). The selenium ions usually come in the form of selenides ( 2 - span> ) and selenate ( SeO 2 -
4 ). The tellurium ions often come in the form of tellurate ( TeO 2 - style = "font-size: inherit; line-height: inherit; vertical-align: baseline"> 4 ). Molecules containing metals bound to chalcogens are commonly used as minerals. For example, pyrite (FeS 2 ) is iron ore, and rare calaverite minerals are ditelluride (Au, Ag) Te 2 .
Although all the 16 group elements of the periodic table, including oxygen, can be defined as chalcogens, oxygen and oxides are usually distinguished from chalcogens and chalcogenides. The term chalcogenide is more commonly used for sulphides, selenides, and tellurides, not for oxides.
Except for polonium, all chalcogens are almost identical to each other chemically. They all form an X 2 - ion when reacting with an electropositive metal.
Mineral sulfides and analogue compounds produce gases in reaction with oxygen.
Maps Chalcogen
​​Compound
With halogen
The balcony also forms a compound with a halogen known as chalcohalides . These compounds are known as chalcogen halides. The majority of simple chalcogen halides are well known and widely used as chemical reagents. However, more complicated chalcogen halides, such as sulfenyl, sulfonyl, and sulfuryl halides, are less known by science. Of compounds consisting purely of chalcogens and halogens, there are a total of 13 chalcogen fluorides, nine chalcogen chlorides, eight chalcogen bromides, and six known chalcogen iodides. The heavier chalcogen halides often have significant molecular interactions. Sulfur fluoride with low valence is quite unstable and little is known about their properties. However, high-valence sulfur fluorine, such as sulfur hexafluoride, is stable and well known. Sulfur tetrafluoride is also known as sulfur fluoride. Several selenium fluorides, such as selenium difluoride, have been produced in small quantities. The crystalline structure of both selenium tetrafluoride and tellurium tetrafluoride is known. Chlorine chloride and bromide have also been explored. In particular, selenium dichloride and sulfur dichloride may react to form organic selenium compounds. Dichalcogen dihalides, such as Se 2 Cl 2 are also known to exist. There is also a compound of chalcogen-halogen. This includes SeSX, with X being chlorine or bromine. Such compounds may be formed in a mixture of sulfur dichloride and selenium halide. These compounds are structurally recently characterized, in 2008. In general, selenium and disulfur chloride and bromide are useful chemical reagents. Chalcogen halides with attached metal atoms are soluble in an organic solution. One example of such compounds is MoS 2 Cl 3 . Unlike selenium chloride and bromide, selenium iodide has not been isolated, in 2008, although it is likely that they occur in solution. Diselenium diiodide, however, occurs in equilibrium with the selenium atoms and iodine molecules. Some low-valence halide eggs, such as Te 2 Cl 2 and Te 2 Br 2 , form a polymer when in solid state. This tellurium halide can be synthesized by the reduction of pure tellurium with superhydride and reacting the product produced with the tellurium tetrahalide. The dielururium dihalides tend to be less stable because the halides are lower in the number of atoms and the atomic mass. Eggs also form iodides with fewer iodine atoms than diiodies. These include TeI and Te 2 I. These compounds have extended the structure in a solid state. Halogen and chalcogens can also form halochalcogenate anions.
Organic
Alcohol, phenol and other similar compounds contain oxygen. However, in the thiols, selenol and egg eyes; sulfur, selenium, and tellurium replace oxygen. Tiol is better known than the selenol or egg of the eye. Tiol is the most stable chalcogenol and tellurol is the most stable, unstable in heat or light. Other organic chalcogen compounds include tioethers, selenoethers and telluroethers. Some of them, such as dimethyl sulphide, diethyl sulphide, and dipropyl sulfide are commercially available. Selenoethers in the form of R 2 Se or RSeR. Telluroethers such as dimethyl telluride are usually prepared in the same way as tioethers and selenoethers. Organic chalcogen compounds, especially sulfur organic compounds, tend to smell unpleasant. Dimethyl telluride also smells unpleasant, and selenophenol is known for its "metaphysical odor". There are also thioketones, selenoketones, and telluroketones. Of these, thioketones are the most well studied with 80% of chalcogenoketones paper being around them. Selenocetones make up 16% of the paper and tellurochetes make up 4% of them. Thioketones have well-studied non-linear electrical and photophysic properties. Selenochetones are less stable than thioconones and telluroketones less stable than selenocetones. Telluroketones have the highest polarity of chalcogenoketones.
With metal
Elemental Chalcogens react with certain lanthanide compounds to form chalcogens-rich lanthanide groups. Chalkogenol Uranium (IV) compounds also exist. There are also transition metal chalcogenols that potentially function as catalysts and stabilize nanoparticles.
There are a large number of metal chalcogenides. One of the most recent discoveries in this group of compounds is Rb 2 Te. There are also compounds in which alkali metals and transition metals such as the transition metal of the fourth period except for copper and zinc. In metal-rich metal chalcogenides, such as Lu 7 Te and Lu 8 Te have a metal crystal lattice domain containing chalcogen atoms. Although these compounds exist, analog chemicals containing lanthanum, praseodymium, gadolinium, holmium, terbium, or ytterbium have not been found, in 2008. Boron groups of aluminum, gallium, and indium metals also form bonds with chalcogen. Ion Ti 3 forms chalcogenide dimer like TiTl 5 Se 8 . The chalcogenide metal dimer also occurs as a lower telluride, such as Zr 5 Te 6 .
With pnictogen
Chalcogen-phosphorus-bonded compounds have been explored for more than 200 years. These compounds include simple phosphorus chalcogenides as well as large molecules with biological roles and phosphorus-kalkon compounds with metal clusters. These compounds have many applications, including strike-anywhere and quantum dots. A total of 130,000 compounds with at least one phosphorus-sulfur bond, 6000 compounds with at least one phosphorus-selenium bond, and 350 compounds with at least one phosphorurium bond have been found. The further decrease in chalcogen-phosphorus compounds below the periodic table is due to reduced bond strength. Such compounds tend to be at least one atom of phosphorus at its center, surrounded by four balconies and side chains. However, some phosphorus-chalcogen compounds also contain hydrogen (such as secondary chalcogenides phosphine) or nitrogen (such as dichalcogenoimidodiphosphate). Selenides phosphorus is usually more difficult to handle phosphorus phosphorus, and the compound in the form P x Te y has not been found. Kharkokin is also bound to other pnictogen, such as arsenic, antimony, and bismuth. Chiancogen pnictides that are heavier tend to form polymers such as ribbons, not individual molecules. The chemical formula of this compound includes Bi 2 S 3 and Sb 2 Se 3 . Pnictida chalcogen Ternary is also known. Examples include P 4 O 6 Se and P 3 SbS 3 . salt containing chalcogens and pnictogens also exist. Almost all chalcogen pnictida salts are usually in the form of P <3 sub 3 - , where Pn is pnictogen and E is a chalcogen. Tertiary phosphine may react with chalcogens to form compounds in the form of R 3 PE, where E is a chalcogen. When E is sulfur, these compounds are relatively stable, but they are less so when E is selenium or tellurium. Similarly, secondary phosphine may react with chalcogens to form secondary chalcogenides phosphine. However, this compound is in equilibrium with chalcogenophosphinous acid. Chalcogenides secondary phosphary is a weak acid. Binary compounds consist of antimony or arsenic and chalcogen. These compounds tend to be colorful and can be created by the reaction of the constituent elements at a temperature of 500 to 900 ° C (932 to 1,652 ° F).
More
Chalcogens form single bonds and double bonds with other carbon group elements of carbon, such as silicon, germanium, and tin. Such compounds are usually formed from group carbon halide reactions and chalcogenol salts or chalcogenol bases. Cyclic compounds with chalcogens, carbon group elements, and boron atoms exist, and occur from the reaction of boron dichalcogenates and metal halides of the carbon group. Compounds are in the form of M-E, where M is silicon, germanium, or lead, and E is sulfur, selenium or tellurium has been found. This is formed when a carbon hydride group reacts or when a heavier carbene version reacts. Sulfur and tellurium may bind with organic compounds containing silicon and phosphorus.
All chalcogens form hydrides. In some cases this occurs with a chalcogens bond with two hydrogen atoms. However, the polysium and polyunium eggs and hydrides are both volatile and highly volatile. Also, oxygen can bind hydrogen in a 1: 1 ratio as in hydrogen peroxide, but it is unstable.
Compound calkon form a number of interchalcogens. For example, sulfur forms toxic sulfur dioxide and sulfur trioxide. Eggs also form oxides. There are several chalcogen sulfides as well. These include selenium sulphide, the ingredients in some shampoos.
Since 1990, a number of borides with chalcogens attached to it have been detected. Chalcogens in these compounds are mostly sulfur, although some do contain selenium. One of these chalkogenic borides consists of two molecules of dimethyl sulfide bonded to a boron-hydrogen molecule. Other important boron-chalcogen compounds include the macropolyhedral system. Such compounds tend to display sulfur as a chalcogen. There are also chalcogen borides with two, three, or four chalcogens. Many of them contain sulfur but some, such as Na 2 B 2 Se 7 contain selenium instead.
History
Initial discovery
Sulfur has been known since ancient times and is mentioned in the Bible fifteen times. It was known to the ancient Greeks and was generally mined by the ancient Romans. It was also historically used as a component of Greek fire. In the Middle Ages, it was an important part of the alchemical experiment. In the 1700s and 1800s, scientists Joseph Louis Gay-Lussac and Louis-Jacques ThÃÆ' Â © nard prove sulfur as a chemical element.
Early attempts to separate oxygen from the air were hampered by the fact that the air was considered a single element until the 17th and 18th centuries. Robert Hooke, Mikhail Lomonosov, Ole Borch, and Pierre Bayden all managed to create oxygen, but did not realize it at the time. Oxygen was discovered by Joseph Priestley in 1774 when he focused sunlight on samples of mercury oxide and collected the resulting gas. Carl Wilhelm Scheele also created oxygen in 1771 by the same method, but Scheele did not publish the results until 1777.
Telurium was first discovered in 1783 by Franz Joseph MÃÆ'¼ller von Reichenstein. He found tellurium in a sample of what is now known as calaverite. MÃÆ'¼ller assumes that the sample is pure antimony, but the tests he did on the sample did not match this. Muller then suspects that the sample is bismuth sulphide, but tests confirm that the sample is not like that. For several years, Muller pondered the matter. Eventually he realized that the sample was binding gold with an unknown element. In 1796, MÃÆ'¼ller sent partial samples to German chemist Martin Klaproth, who purified undiscovered elements. Klaproth decided to call the element of tellurium after the Latin word for earth.
Selenium was discovered in 1817 by JÃÆ'¶ns Jacob Berzelius. Berzelius sees reddish-brown sediments at the sulfuric acid manufacturing plant. The sample is considered to contain arsenic. Berzelius initially thought that the sediment contained tellurium, but eventually realized that the sediment contained a new element, which he named selenium after the Greek moon goddess Selene.
Periodic table locates
Three of the chalcogens (sulfur, selenium, and tellurium) are part of the discovery of periodicity, since they are among a series of triad elements in the same group recorded by Johann Wolfgang DÃÆ'¶bereiner as having the same properties. Around 1865 John Newlands produced a series of papers in which he listed elements in order of increasing atomic weight and similar physical and chemical properties that reappeared at interval eight; he likened that periodicity to the musical octave. The versions include "group b" consisting of oxygen, sulfur, selenium, tellurium, and osmium.
After 1869, Dmitri Mendeleev proposed his periodic table to place oxygen at the top of the "group VI" above sulfur, selenium, and tellurium. Chromium, molybdenum, tungsten, and uranium are sometimes included in this group, but they will later be rearranged as part of the VIB group; uranium will then be transferred to the actinide series. Oxygen, together with sulfur, selenium, tellurium, and then polonium will be grouped in the VIA group , until the group name is changed to group 16 in 1988.
Modern discovery
At the end of the 19th century, Marie Curie and Pierre Curie discovered that pitchblende samples emit four times as much radioactivity as can be explained by the presence of uranium alone. The Curies collect several tons of pitchblende and refine them for several months until they have a pure sample of polonium. The discovery officially took place in 1898. Prior to the invention of particle accelerators, the only way to make polonium was to extract it for several months from uranium ore.
The first attempt to create livermorium was from 1976 to 1977 in LBNL, which bombed curium-248 with calcium-48, but was unsuccessful. After several failed attempts in 1977, 1998 and 1999 by research groups in Russia, Germany, and the United States, livermorium was successfully created in 2000 at the Joint Institute for Nuclear Research by bombarding the 248th curium-atom with a calcium-48 atom. This element is known as ununhexium until it is officially named livermorium in 2012.
Etymology
In the 19th century, Jons Jacob Berzelius suggested summoning elements in groups of 16 "amphigens", as elements in groups that form amphid salts (oxyacids salts). This term received some usage in the early 1800s but is now worn. The name chalcogen comes from the Greek word ?????? (chalkos, literally "copper"), and ????? (genes, birth, gender, kindle). It was first used in 1932 by the Wilhelm Biltz group at Hanover University, where it was proposed by Werner Fischer. The word "chalcogen" gained popularity in Germany during the 1930s because the term was analogous to "halogen". Although the literal meaning of the Greek words implies that
The name oxygen comes from the Greek word oxy gene , which means "acid-forming". The Sulfur name is derived from the Latin sulfurium or the Sanskrit word sulvere ; both terms are ancient words for sulfur. Selenium is named after the Greek goddess of the moon, Selene, to match the elemental tellurium found earlier, whose name comes from the Latin telus , which means earth. Polonium is named after the birth country of Marie Curie, Poland. Livermorium was named for Lawrence Livermore National Laboratory.
Genesis
The four lightest chalcogens (oxygen, sulfur, selenium, and tellurium) are all primordial elements on Earth. Sulfur and oxygen occur as the constituent copper ores and selenium and tellurium occur in small traces in the ore. Polonium forms naturally after the decay of other elements, although not primordial. Livermorium does not occur naturally at all.
Oxygen forms 21% of the atmosphere by weight, 89% of water by weight, 46% of the Earth's crust by weight, and 65% of the human body. Oxygen also occurs in many minerals, which are found in all mineral oxides and mineral hydroxides, and in many other mineral groups. Stars at least eight times the mass of the sun also produce oxygen at their nuclei through nuclear fusion. Oxygen is the third most abundant element in the universe, forming 1% of the universe by weight.
Sulfur makes up 0.035% of the Earth's crust by weight, making it the 17th most abundant element there and forming 0.25% of the human body. This is the main component of the soil. Sulfur forms 870 parts per million of seawater and about 1 part per billion of atmosphere. Sulfur can be found in elemental form or in the form of sulphide minerals, sulfate minerals, or sulfosalt minerals. Stars at least 12 times the mass of the sun produce sulfur in their nuclei through nuclear fusion. Sulfur is the tenth most abundant element in the universe, forming 500 parts per million of the universe by weight.
Selenium forms 0.05 parts per million of the Earth's crust by weight. This makes it the 67th most abundant element in the earth's crust. Selenium forms an average of 5 parts per million of land. Seawater contains about 200 parts per trillion of selenium. The atmosphere contains 1 nanogram of selenium per cubic meter. There is a group of minerals known as selenat and selenit, but there are not many minerals in these groups. Selenium is not produced directly by nuclear fusion. Selenium forms 30 parts per billion of the universe by weight.
There are only 5 parts per billion of eggs in the earth's crust and 15 parts per billion of eggs in sea water. Telurium is one of the eight or nine most abundant elements in the Earth's crust. There are several dozen minerals tellurate and mineral telluride, and tellurium occurs in some minerals with gold, such as sylvanite and calaverite. Eggs form 9 parts per billion of the universe by weight.
Polonium occurs only in a small number of traces on earth, through radioactive decay of uranium and thorium. These are present in uranium ore in concentrations of 100 micrograms per metric ton. A small amount of polonium is present in the soil and thus in most foods, and thus in the human body. The crust contains less than 1 part per billion of polonium, making it one of the ten rarest metals on earth.
Livermorium is always produced artificially in particle accelerators. Even when produced, only a small number of atoms at a time are synthesized.
Chalcophile Elements
The elements of chlorophyll are the elements that remain at or near the surface as they join chalcogens in addition to oxygen, forming a compound that does not sink into the nucleus. Chalcophile ("chalcogen-loving") elements in this context are heavier metals and nonmetals that have a lower affinity for oxygen and prefer to bond with heavier chalcogen sulfur as sulphides. Because sulphide minerals are much denser than silicate minerals formed by lithophile elements, chalcophile elements are separated under lithophyll at the time of first crystallization of the Earth's crust. This causes their depletion in the Earth's crust relative to their solar abundance, although this depletion has not reached the level found with the siderophile element.
Production
About 100 million metric tons of oxygen is produced each year. Oxygen is most often generated by fractional distillation, where air is cooled to a liquid, then warmed, allowing all air components except oxygen to switch to gas and escape. Air fractional distillation several times can produce 99.5% pure oxygen. Another method that produces oxygen is to send a dry and clean air stream through a molecular sieve layer made of zeolite, which absorbs nitrogen in the air, leaving 90 to 93% pure oxygen.
Sulfur can be mined in its elemental form, although this method is no longer as popular as it used to be. In 1865, large elemental sulfur deposits were found in the states of Louisiana and Texas of the United States, but were difficult to extract at the time. In the 1890s, Herman Frasch emerged with a solution of sulfur melting with super-hot steam and pumping sulfur onto the surface. Sulfur is now more often extracted from oil, natural gas, and tar.
The world's selenium production is about 1500 metric tons per year, of which about 10% is recycled. Japan is the largest producer, producing 800 metric tons of selenium per year. Other large producers include Belgium (300 metric tons per year), the United States (over 200 metric tons per year), Sweden (130 metric tons per year), and Russia (100 metric tons per year). Selenium can be extracted from waste from a copper electrolysis refining process. Another method for producing selenium is by planting collecting crop selenium such as vetch milk. This method can produce three kilograms of selenium per acre, but it is not common.
Tellurium is mostly produced as a by-product of copper processing. The eggs can also be enhanced by the reduction of sodium telluride electrolyte. The world's egg production is between 150 and 200 metric tons per year. The United States is one of the largest producers of tellurium, producing about 50 metric tons per year. Peru, Japan, and Canada are also large producers of tellurium.
Until the creation of nuclear reactors, all polonium must be extracted from uranium ore. In modern times, most of the isotopes of polonium are produced by bombarding bismuth with neutrons. Polonium can also be produced by high neutron flux in a nuclear reactor. About 100 grams of polonium is produced every year. All polonium produced for commercial purposes are manufactured at Ozersk nuclear reactors in Russia. From there, taken to Samara, Russia for purification, and from there to St. Petersburg for distribution. The United States is the largest consumer of polonium.
All livermorium are produced artificially in a particle accelerator. The first successful livermorium production was achieved by bombarding the curium-248 atom with a calcium-48 atom. In 2011, about 25 livermorium atoms have been synthesized.
Apps
Steelmaking is the most important use of oxygen; 55% of all oxygen generated into this application. The chemical industry also uses oxygen in large quantities; 25% of all oxygen generated into this application. The remaining 20% ​​of the oxygen produced is largely divided between medical use, water treatment (such as oxygen killing some types of bacteria), rocket fuel (in liquid form), and metal cutting.
Most of the resulting sulfur is converted into sulfur dioxide, which is then converted to sulfuric acid, a very common industrial chemical. Other common uses include being the main material of gunpowder and Greek fire, and are used to change soil pH. Sulfur is also mixed into rubber to vulcanize. Sulfur is used in several types of concrete and fireworks. 60% of all sulfuric acid produced is used to produce phosphoric acid.
About 40% of all selenium produced goes into glass making. 30% of all selenium produced goes into metallurgy, including manganese production. 15% of all selenium produced goes into agriculture. Electronic goods such as photovoltaics claim 10% of all selenium produced. Pigments account for 5% of all selenium produced. Historically, machines such as copiers and light gauges use a third of all selenium produced, but these applications continue to decline.
Egg suboxide, a mixture of tellurium and tellurium dioxide, are used in the rewritable data layer of some CD-RW disks and DVD-RW disks. Bismuth telluride is also used in many microelectronic devices, such as photoreceptors. Eggium is sometimes used as an alternative to sulfur in vulcanised rubber. Cadmium telluride is used as a high efficiency material in solar panels.
Some polonium applications are related to elemental radioactivity. For example, polonium is used as an alpha particle generator for research. The polonium alloy with beryllium provides an efficient neutron source. Polonium is also used in nuclear batteries. Most of the polonium is used in antistatic devices. Livermorium has no use whatsoever because of its extreme scarcity and short half-life.
Organochalcogen compounds are involved in semiconductor processes. This compound also has chemical features of ligand and biochemistry. One application of chalcogens itself is to manipulate the redox pair in supramolar chemistry (chemistry involving non-covalent bonding interactions). This application leads to applications such as crystal packing, large molecular assembly, and biological pattern recognition. The interaction of secondary bonds of larger chalcogens, selenium and tellurium, can make organic solvent-holding acetylene nanotubes. Chalcogen interactions are useful for conformational analysis and stereoelectronic effects, among others. Chalcogenides with ties also have applications. For example, divalent sulfur can stabilize carbanion, cationic center, and radical. Chalcogens may negotiate on ligands (such as DCTO) properties such as being able to convert Cu (II) to Cu (I). Studying chalcogenic interactions gives access to radical cations, which are used in mainstream synthetic chemistry. An important biological metallic redox center may be tuned by ligand interactions containing chalcogens, such as methionine and selenocysteine. Also, chalcogen through bonds can provide insight into the electron transfer process.
The role of biology
Oxygen is required by almost all organisms for the purpose of generating ATP. It is also a key component of most other biological compounds, such as water, amino acids and DNA. Human blood contains a large amount of oxygen. Human bone contains 28% oxygen. Human tissue contains 16% oxygen. Humans 70 kilograms generally contain 43 kilograms of oxygen, mostly in the form of water.
All animals need significant amounts of sulfur. Some amino acids, such as cysteine ​​and methionine, contain sulfur. Plant roots pick up sulfate ions from the soil and reduce them to sulfide ions. Metalloproteins also use sulfur to stick to useful metal atoms in the body and sulfur also attaches to toxic metal atoms like cadmium to transport them to the salvation of the liver. On average, humans consume 900 milligrams of sulfur every day. Sulfur compounds, such as those found in skunk sprays often have a strong odor.
All animals and some plants require a certain amount of selenium, but only for some special enzymes. Humans consume an average of between 6 and 200 micrograms of selenium per day. Mushrooms and brazil nuts are well known for their high selenium content. Selenium in food is most often found in the form of amino acids such as selenocysteine ​​and selenomethionine. Selenium can protect against heavy metal poisoning.
Unknown eggs are needed for animal life, although some mushrooms may incorporate them in compounds in the selenium site. Microorganisms also absorb tellurium and remove dimethyl telluride. Most of the eggs in the bloodstream are excreted slowly in the urine, but some are converted into dimethyl telluride and released through the lungs. On average, humans ingest about 600 micrograms of tellurium every day. Plants can take some of the eggs from the soil. Onions and garlic have been found to contain as much as 300 parts per million of eggs in dry weight.
Polonium has no biological role, and is highly toxic because of radioactivity.
Toxicity
Oxygen is generally non-toxic, but oxygen toxicity has been reported when used in high concentrations. In the form of elemental gases and as a water component, it is essential for almost all life on earth. Nonetheless, liquid oxygen is very dangerous. Even oxygen gases are dangerously overdone. For example, sports divers sometimes sink because of seizures caused by breathing pure oxygen at a depth of more than 10 meters (33 feet) underwater. Oxygen is also toxic to some bacteria. Ozone, allotropic oxygen, is toxic to most life. May cause lesions in the respiratory tract.
Sulfur is generally non-toxic and even an essential nutrient for humans. However, in its elemental form can cause redness in the eyes and skin, burning sensations and coughing if inhaled, burning sensation and diarrhea if swallowed, and may irritate the mucous membranes. Excess sulfur can be toxic to cows because microbes in cow rumensia produce toxic hydrogen sulfide when reacting with sulfur. Many sulfur compounds, such as hydrogen sulfide (H 2 S) and sulfur dioxide (SO 2 ) are highly toxic.
Selenium is a nutrient needed by humans in the order of tens or hundreds of micrograms per day. Doses of over 450 micrograms can be toxic, which causes bad breath and body odor. Extensive low level exposure, which can occur in some industries, leads to weight loss, anemia, and dermatitis. In many cases of selenium toxicity, selenous acid forms in the body. Hydrogen selenide (H 2 Se) is highly toxic.
Exposure to eggs can produce unpleasant side effects. As little as 10 micrograms of tellurium per cubic meter of air can cause unpleasant breathing, depicted to smell like rotten garlic. Acute acetic poisoning can cause vomiting, intestinal inflammation, internal bleeding, and respiratory failure. Extended exposure to low levels of the eggs causes fatigue and indigestion. Sodium tellurite (Na 2 TeO 3 ) turns off in an amount of about 2 grams.
Polonium is harmful both as an alpha particle emitter and because it is chemically toxic. If ingested, polonium-210 is one billion times toxic as hydrogen cyanide by weight; has been used as a murder weapon in the past, the most famous for killing Alexander Litvinenko. Polonium poisoning can cause nausea, vomiting, anorexia, and lymphopenia. It can also damage the hair follicles and white blood cells. Polonium-210 is only harmful if ingested or inhaled because the emission of alpha particles can not penetrate human skin. Polonium-209 is also toxic, and can cause leukemia.
See also
- Chalcogenide
- Chalcogenides gold
- Halogen
- Interchalcogen
- Pnictogen
References
External links
- Media associated with the Periodic group table 16 on Wikimedia Commons
Source of the article : Wikipedia
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