Find the discovery history, characteristics and all relevant knowledge of carbon.

Classification: science and engineering disciplines

Analysis:

The discovery history of carbon

Carbon can be said to be one of the earliest elements that human beings came into contact with and used. Since human beings appeared on the earth, they have been in contact with carbon. Because lightning burning wood will leave charcoal, after animals are burned to death, bone carbon will remain. After human beings learned to make a fire, carbon became a permanent "partner" of human beings, so carbon is an element that has been known since ancient times. The exact date of carbon discovery is not verified, but it can be seen from the list of elements compiled by lavoisier (1789) that carbon appears as an element. Carbon played an important role in the development of ancient phlogiston theory. According to this theory, carbon is not an element, but a pure phlogiston. Because he studied the combustion of coal and other chemicals, lavoisier first pointed out that carbon is an element.

There are three allotropes of carbon in nature-diamond, graphite and C 60. Diamond and graphite have long been known. Lavoisier made experiments on the combustion of diamond and graphite, and determined that the combustion of these two substances produced CO 2, from which he concluded that diamond and graphite contained the same "basis", that is, carbon. Lavoisier is the first country to put carbon in the list of elements. C 60 was discovered in 1985 by the chemist Harry Kraut of Rice University in Houston, USA. It is a spherical stable carbon molecule composed of 60 carbon atoms, and it is the third allotrope of carbon, second only to diamond and graphite.

The Latin name of Carbon comes from the word carbon, which means "coal". It first appeared in the book Chemical Nomenclature edited by lavoisier and others in 1787. The English name of carbon is Corbon.

chemfans/05huaxveshihua/C

carbon

Carbon is a nonmetallic element, which is located in the second periodic group of the periodic table of elements. Its chemical symbol is C, atomic number is 6, and its electronic configuration is [He]2s22p2. Carbon is a very common element, which exists widely in the atmosphere and crust in various forms. The understanding and utilization of simple carbon has a long history, and a series of compounds of carbon-organic matter are the basis of life.

Latin is Carbonium, which means "coal, charcoal". The Chinese character "carbon" is composed of the word "carbon" of charcoal and stones beside solid nonmetallic elements, which sounds like carbon.

Character; Role; letter

Elemental carbon is usually an odorless and tasteless solid. The physical and chemical properties of elemental carbon depend on its crystal structure, and its appearance, density and melting point are different. It is known that elemental carbon exists in various allotropes:

graphite

diamond

Fullerenes (also known as buckyballs)

Amorphous carbon (amorphous, not really alien, internal structure is graphite)

Carbon nanotubes (CNTs)

Hexagonal diamond (also known as hexagonal diamond) has the same bond type as diamond, but the atoms are arranged in a hexagon.

Zhao graphite (Chao Shi, which is produced by the collision between graphite and meteorites, and the atoms are arranged in a hexagonal shape)

Mercury tetrahedrite structure (an imaginary structure, the hexagonal layer is twisted into a "negative curvature" saddle shape due to the appearance of heptagons)

Carbon fiber (fiber made of small pieces piled up in long chains)

Carbon aerogels (carbon aerogels, porous structure with extremely low density, similar to the well-known silicon aerogel).

Carbon nano-foam (cobweb-like, with fractal structure, density is 1% of that of carbon aerogels, with ferromagnetism).

The two most common simple substances are high hardness diamond and soft and greasy graphite, and their crystal structures and bonding types are different. Each carbon of a diamond is tetrahedrally 4 coordinated, similar to aliphatic compounds; Each carbon of graphite is a triangle 3 coordination, which can be regarded as infinite benzene rings fused together.

The chemical properties of elemental carbon are relatively stable at room temperature and insoluble in water, dilute acid, dilute alkali and organic solvents.

isotope

There are twelve known isotopes, ranging from carbon 8 to carbon 19. Among them, carbon 12 and carbon 13 are stable, and the rest are radioactive. Among them, the half-life of carbon 14 is more than 5000 years, and others are less than half an hour.

In the nature of the earth, carbon 12 accounts for 98.93% of all carbon, while carbon 13 accounts for 1.07%. The atomic weight of C is taken as the weighted average of carbon 12 and carbon 13 isotopic abundances, and 12.05438+0 is generally taken in the calculation.

Carbon 12 is the scale of moles defined in the international system of units, and the number of atoms contained in 12g carbon 1 2 is1mole. Carbon 14 is widely used to date antiquities because of its long half-life.

cohere

Carbon atoms are generally tetravalent and need four single electrons, but its ground state has only two single electrons, so hybridization is always needed when bonding. The most common hybridization method is sp3 hybridization, which makes full use of four valence electrons, evenly distributed in four orbits, and belongs to isotropic hybridization. This structure is completely symmetrical, and it is a stable σ bond after bonding, and it is very stable without the repulsion of lone electron pairs. All the carbon atoms in diamond are combined in this way. The carbon atoms of alkanes also belong to this category.

According to requirements, carbon atoms can also be hybridized with sp2 or sp. Both of these methods appear in the case of re-bonding, and the non-hybridized P orbitals are perpendicular to the hybridized orbitals, forming π bonds with the P orbitals of adjacent atoms. The carbon atom connecting the double bond in olefins is sp 2 hybridization.

Because sp2 hybridization can make atoms coplanar, when multiple double bonds appear, all P orbitals perpendicular to the molecular plane may overlap with each other to form a conjugated system. Benzene is the most typical conjugated system, which loses some properties of double bonds. All carbon atoms in graphite are in a large conjugated system, and each layer corresponds to one carbon atom.

multiple

Among the compounds of carbon, only the following compounds belong to inorganic substances:

Oxides of carbon: carbon monoxide, carbon dioxide

Carbonate, bicarbonate

Cyanide A series of pseudohalogens, pseudohalides and pseudohalides: cyanogen, cyanogen oxide and thiocyanate.

Other carbon-containing compounds are organic compounds. Because the bonds formed by carbon atoms are relatively stable, the number and arrangement of carbon and the types and positions of substituents in organic compounds are very arbitrary, which leads to the phenomenon of a large number of organic substances. At present, among the compounds discovered by human beings, organic matter accounts for the vast majority. The properties of organic compounds are quite different from those of inorganic compounds. They are generally flammable and insoluble in water, and their reaction mechanism is complicated. Now they have formed an independent branch of organic chemistry.

Be distributed

Carbon exists in nature (for example, in the form of diamond and graphite), and is the most important component of coal, oil, asphalt, limestone, other carbonates and all organic compounds, and its content in the earth's crust is about 0.027%. Carbon is the largest element in the dry weight of organisms. Carbon also circulates in the earth's atmosphere and stratosphere in the form of carbon dioxide.

Carbon exists in most celestial bodies and their atmospheres.

find

Diamonds and graphite have been known since prehistoric times. Fullerenes were discovered in 1985, and then a series of carbon elements with different arrangements were discovered.

Isotope carbon 14 was discovered in 1940.

Elemental extraction

diamond

Diamonds, that is, diamonds, can find concentrated massive mineral deposits, and there are usually impurities when mining. Use other diamond powder to cut off impurities and grind them into finished products. Generally, half of the mass will be lost during cutting and grinding.

graphite

use

Carbon and its compounds are widely used in industry and medicine.

By measuring the content of carbon 14 in antiquities, we can know its age, which is called carbon 14 dating method.

Graphite can be directly used as charcoal pen, or mixed with clay in a certain proportion to make lead cores with different hardness. Besides decoration, diamonds can also make cutting tools sharper. Amorphous carbon is used to absorb toxic gases and waste gases because of its huge surface area. Fullerenes and carbon nanotubes are very useful for nanotechnology.

Carbon is one of the components of steel.

Carbon can chemically combine with itself to form a large number of compounds, which is an important molecule in biology and commerce. Most molecules in organisms contain carbon. Carbon compounds are generally obtained from fossil fuels, and then separated and further synthesized into various products needed for production and life, such as ethylene and plastics.

Physical and chemical characteristics

Overall characteristics

Name, symbol, serial number C, C, 6

Series nonmetal

Series, period, element partition 14 series (IVA), 2, p

The density and hardness are 2267kg/m3,

0.5 (graphite)

10.0 (diamond)

Color and appearance black (graphite)

Colorless (diamond)

Crustal content without data.

Atomic properties