carbon Definition and Topics - 25 Discussions

Carbon (from Latin: carbo "coal") is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three isotopes occur naturally, 12C and 13C being stable, while 14C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity.Carbon is the 15th most abundant element in the Earth's crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon's abundance, its unique diversity of organic compounds, and its unusual ability to form polymers at the temperatures commonly encountered on Earth enables this element to serve as a common element of all known life. It is the second most abundant element in the human body by mass (about 18.5%) after oxygen.The atoms of carbon can bond together in diverse ways, resulting in various allotropes of carbon. Well-known allotropes include graphite, diamond, amorphous carbon and fullerenes. The physical properties of carbon vary widely with the allotropic form. For example, graphite is opaque and black while diamond is highly transparent. Graphite is soft enough to form a streak on paper (hence its name, from the Greek verb "γράφειν" which means "to write"), while diamond is the hardest naturally occurring material known. Graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials. All carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form at standard temperature and pressure. They are chemically resistant and require high temperature to react even with oxygen.
The most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and transition metal carbonyl complexes. The largest sources of inorganic carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil, and methane clathrates. Carbon forms a vast number of compounds, more than any other element, with almost ten million compounds described to date, and yet that number is but a fraction of the number of theoretically possible compounds under standard conditions. For this reason, carbon has often been referred to as the "king of the elements".

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  1. P

    A Phase diagram of Carbon at large electric fields.

    I am wondering if the phase diagram of Carbon has been explored at very large electric fields. Can one make any theoretical guesses ? In specific I am interested in Pressure Vs Electric field and Electric field vs Temperature at fixed temperature and pressure respectively.
  2. Q

    B Why is Carbon considered volatile?

    Carbon is considered volatile by planetary science, eg Moon lacks volatiles and thus lacks carbon. However volatiles are defined as "elements or substances with low boiling point", but Carbon boiling point is very high! Its sublimation point is 3900K, so it should be refractory and not volatile...
  3. C

    Carbon sequestration, how does it work? Is it practical?

    Hi All, I understand carbon sequestration in the simplest sense is capturing and storing carbon. As seen in the title, I'm going to split this into two sections. i) How does it work? I imagine that trees, in a sense are doing this. They take in the carbon from our atmosphere and is stored...
  4. T

    NASA NASA Challenge - CO2 Conversion

    NASA is looking for a process to use CO2 as a Carbon source on Mars; ultimate goal is to use the Carbon in the synthesis of other products. $50,000 prize. Open to U.S. citizens, permanent residents, and U.S. business entities, work must be done in the U.S...
  5. Muhammad Danish

    Organic Chemistry, Hydrocarbons

    Homework Statement Homework Equations The Attempt at a Solution C=C double bonds means that it is not an Alkane because an Alkane is saturated hydrocarbon. So the answer should be from A, B or C.
  6. Y

    How strong a long chain of c=c double bonds will be?

    How strong a long chain of carbon carbon double bonds will be compared to nano tubes? H>c=c=c=c=c=c=c=c=...............=c=c=c=c=c=c=c=c=c=c=c=c<H
  7. J

    How to specify carbon fibre material properties in ANSYS ACP

    Hey there, my honours year thesis is on the design and analysis of a carbon fibre wheel for a Formula Student racecar. However, I am unable to obtain carbon fibre material properties to input into the Engineering Data section. I am required to specify the Youngs Modulus in the x, y and z...
  8. H

    Method Of Loading Carbon Molecular Sieve To Psa Tank

    Dear all I want to loading about 14 ton of CMS (Carbon Molecular Sieve) into a PSA Nitrogen Producer tank. The tank is 5 meter tall with 2 m in diameter. What is the best, simplest and fastest method to load the pellet of CMS into that big tank? I consider this mortar screw pump and connect...
  9. R

    Trees are natural

    A tree seed takes water and minerals(?) from the ground, carbon and oxygen(?) from the air, and heat and light(?) from the sun. When a tree dies and dries up, it can be used as firewood, a source of energy. Is there a way to capture that energy without the seed-tree scenario? i.e., but can we...
  10. N

    Shouldn't Carbon-14 concentration be the same everywhere?

    Why is it that newer organic matter has more carbon-14 than older organic matter? Isn't carbon constantly recycled, because of the carbon cycle? So C14-depleted carbon from old matter would enter the atmosphere, then be breathed in by new organic matter. The new matter would start off with...
  11. V

    B Safety and legality of carbon-11

    This is a pretty self-explanatory question; I was wondering how safe carbon-11 is for human beings; is it extremely radioactive and harmful, or safe for the average Joe to handle with the right casing/equipment. Furthermore, is owning this isotope illegal/highly regulated, or can people easily...
  12. marcophys

    What breaks down burnt carbon deposits?

    I have an aerosol based 'oven, and chimney cleaning' product. Here are the contents: Aqua Propylene Glycol Butane Ethanolamine Cocamide DEA Propane Sodium Hydroxide Sodium Laureth Sulfate Xanthan Gum Parfum From the list, it appears that the only active ingredient is Sodium Hydroxide...
  13. Joshua L

    B Hamiltonian of Carbon-14?

    Hey, here's a quick question: What is the Hamiltonian operator corresponding to a decaying Carbon-14 atom. Any insight is quite appreciated!
  14. 3DTOPO

    Conductive Silicon Carbide [Carborundum]

    I am trying to create a conductive Silicon Carbide (SiC) heating element. The US patent 650234 "Process of making carborundum articles", filed in 1899 states essentially that crushed SiC crystals can be be glued together (using diluted glue) then sintered. It states that the addition of 15-20%...
  15. copper-head

    Making Carbon pellets with PVA

    Hey there. I am making Carbon pellets using polyvinyl alcohol as a binder to help shape the pellets. I would like to measure the pellet's conductivity without being hindered or influence by the conductivity of the PVA. One way to do it is to heat the pellets to 300 degrees and evaporate the PVA...
  16. P

    Why carbon is used in nano technology?

    Hello, I would like to know that why carbon is used in nano technology to build nano tubes and other? Is there any other metal which is used to construct the devices of nano technology?
  17. Jonski

    Energy Intensity of black coal

    Homework Statement Brown coal, energy content 16 MJ/kg, carbon content 65% by weight, burning in a 30% efficient steam power plant. Homework Equations What is the emissions intensity (kg CO2 emitted/kWh delivered) ? Compare this to Hazelwood which is 1.53 tCO2/Mwh 3. The Attempt at a Solution...
  18. N

    Carbon sp3

    Why/How does Carbon's 3rd p-orbital contribute to its bond -- sp3 -- if it's vacant?
  19. MarcozXD

    Should carbon boiling stones be used in O-chem reactions?

    I performed column cromatography on an oil, and used carbon boiling chips but got some weird IR. I used hexanes and acetone as solvents, im trying to figure out some of the spikes, soo im thinking that maybe the boiling stone being carbon could acted as activated carbon and absorbed some organic...
  20. Kior

    Why has CO2 decreased in the history of the Earth?

    I noticed that the Co2 is actually decreasing in the Eon time. My guess is lush vegetations or forests began to grow which absorbed the Co2 by photosynthesis? Would anyone give me any clue?
  21. Kior

    What is the difference between a carbon sink and reservoir?

    I am trying to figure out the difference between a carbon sink and a carbon reservoir. The definition for a carbon sink from wikipedia is that “carbon sinkis a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. ” And the...
  22. Kior

    What is the difference between carbon sink and reservoir?

    I am trying to figure out the difference between a carbon sink and a carbon reservoir. The definition for a carbon sink from wikipedia is that “carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. ” And...
  23. Kior

    Timescale of the biological pump?

    I'm tying to find any clue about the timescale of the biological pump. That the carbon is recycled to the surface ca. 1,000 years is clear but the timescale of the biological pump seems hard to find. There is an report I saw when I was surfing the internet saying that the timescale can range...
  24. M

    Molecular Modeling

    Hi there! Is there an online, hopefully free resource (preferably textbook) that details the process of molecular modeling? Specifically, computationally performing geometry optimizations, vibrational analyses, calculating Raman spectra, detailing the theory behind Hartree-Fock, DFT, post-HF...
  25. R

    Making a Nylon - Fibre Composite

    Hi, I was tasked to design a composite material that will undergo a 3 point bending test. Maximum deflection will be of 15mm and a maximum load of 5kN. The scope of this task is not to prevent failure but to analyse the composite and learn from the design process. Nonetheless the composite...