Carbon Natural Occurrence
Carbon is the chemical element of group-14 in the periodic table occurrence in nature as carbon black, activated carbon, graphite, diamond, oxide, carbonates, and emission products of living organisms with a special position in our life. Therefore, carbon is the key chemical element in all living organisms of our environment forms a large number of compounds except hydrogen, and plays a crucial role in vegetable and animal kingdom.
Carbon dioxide and water of our environment worked up by plants through the agency of chlorophyll and photon rays from sunlight to form carbohydrates. Hence carbohydrates are taken by the animal kingdom and transfer into carbon dioxide and water and the biological cycle formed.
Carbon present in the earth crust to the extent of about 0.08%. Crude oil, coal, and natural gas or hydrocarbon are the most common combined forms. Flakes of graphite and crystalline diamond occurs in metamorphosed sedimentary rocks like quartz.
Chemical Properties of Carbon
The covalent chemistry of carbon compounds explains by thair electronic configuration. Carbon has atomic number 6 with electronic configuration 1s2 2s2 2p2. Therefore, four electrons present in the outer quantum orbital. When we have taken four ionization energy together, the value is very high. Therefore, no compounds know with +4 cation. Instead of forming ionic compounds, in most cases, this atom forms four covalent chemical bonds with sp3 hybridization. It not only forms the single covalent chemical bonding to attain the noble gas electronic configuration but it also formed multiple bonds with sp2 and sp-hybridization.
Carbon naturally posses the +4 oxidation state due to the very low electronegativity but in metal carbides like sodium carbides or calcium carbide, it posses -4 oxidation state.
Isotopes of C-14 and C-12
The principal isotopes of carbon are C-14 and C-12 occurs in nature about 1.11%. These isotopes use in Fourier transform nuclear magnetic resonance (NMR-spectrum) data analysis. The atmospheric CO2 contains about 1.2 × 10-10 percent of radioactive C-14 with half-life 5570 years. C-14 produces by the neutron-proton reaction on nitrogen by thermal cosmic particle radiation. Therefore, the ratio of C-14 and C-12 use in radiocarbon dating.
Isolation of Element
- Among all the natural forms, coke used in large quantities for energy generation in our daily life. Coke is obtained by cooking or high-temperature carbonization of coal in the absence of air.
- Natural graphite obtained in the mixture of mica, quartz, and silicates. Therefore, the mixture washed by flotation and heated with specific heat and hydrochloric acid and hydrofluoric acid in a vacuum. The residual silicon compounds precipitated as SiF4 molecules. Graphite also made by heating silica with coke in an electric furnace at 2500°C for about 24 hours.
- Natural allotrope like diamond uses in large quantities about 18 tones per year in industries and gems. Therefore, only small-size industrial diamonds made synthetically by subjecting graphite to 125000 atm pressure and 3000K temperature. But if we use the metal catalyst, the conversion achieved at 70,000 atm pressure and 2000K temperature.
- Carbon black prepared by incomplete thermodynamics combustion of hydrocarbon but activated carbon prepared by control pyrolysis of organic materials like sawdust or coconut shell.
Uses of Natural Carbon Element
- Coke used in the extraction of iron metals and many other metals in learning chemistry.
- Graphite mainly uses in steelmaking, metal foundries, refractories, in making crucibles, nozzles, fuel cell redox electrode, etc. It also uses highly in lubricant manufacturing plants but important use of graphite in the nuclear power reactors as neurons moderators.
- Diamond, a valuable gemstone uses industrially in making drills and as an abrasive for cutting and polishing.
- Carbon black largely uses in the rubber industry to increases the strength of rubber particularly those used in making car tires.
- Activated carbon is a very efficient absorbent in chemistry uses for absorbing organic pollutants from drinking water and greenhouse gases from the air. Therefore, it largely used as a decolorizing agent in the sugar industry, gas purification, including air pollution and gas masks. Activated carbon also uses in the treatment of sewage water in nature and as a chemical catalyst.