Caurbon

Caurbon (frae Laitin: carbo "coal") is the chemical element wi seembol C an atomic nummer 6. As a member o group 14 on the periodic table, it is nonmetallic an tetravalent—makin fower electrons available tae furm covalent chemical bonds. Thare are three naiturally occurrin isotopes, wi ¹²C an ¹³C bein stable, while ¹⁴C is radioactive, decayin wi a hauf-life o aboot 5,730 years.^[14] Caurbon is ane o the few elements kent syne antiquity.^[15]

Carbon, ₆C

Graphite (left) an diamont (richt), twa allotropes o caurbon
Carbon
Appearance	clear (diamond) & black (graphite)
Standard atomic weight Ar, std(C)	[7001120096000000000♠12.0096, 7001120116000000000♠12.0116] conventional: 7001120110000000000♠12.011
Carbon in the periodic cairt
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium - ↑ C ↓ Si boron ← carbon → nitrogen
Atomic nummer (Z)	6
Group	group 14 (caurbon group)
Period	period 2
Block	p-block
Element category	Reactive nonmetal
Electron confeeguration	[He] 2s2 2p2
Electrons per shell	2, 4
Pheesical properties
Phase at STP	solit
Sublimation pynt	3915 K ​(3642 °C, ​6588 °F)
Density (near r.t.)	amorphous:[1] 1.8–2.1 g/cm3 diamond: 3.515 g/cm3 graphite: 2.267 g/cm3
Treeple pynt	4600 K, ​10800[2][3] kPa
Heat o fusion	117 (graphite) kJ/mol
Molar heat capacity	6.155 (diamond) 8.517 (graphite) J/(mol·K)
Atomic properties
Oxidation states	−4, −3, −2, −1, 0, +1,[4] +2, +3,[5] +4[6] (a mildly acidic oxide)
Electronegativity	Pauling scale: 2.55
Ionisation energies	(more)
Covalent radius	77(sp³), 73(sp²), 69(sp) pm
Van der Waals radius	170 pm
Spectral lines o carbon
Ither properties
Naitural occurrence	primordial
Creestal structur	​diamond cubic (diamond, clear)
Speed o soond thin rod	18350 (diamond) m/s (at 20 °C)
Thermal expansion	0.8 (diamond)[7] µm/(m·K) (at 25 °C)
Thermal conductivity	900-2300 (diamond) 119-165 (graphite) W/(m·K)
Magnetic orderin	diamagnetic[8]
Young's modulus	1050 (diamond)[7] GPa
Shear modulus	478 (diamond)[7] GPa
Bulk modulus	442 (diamond)[7] GPa
Poisson ratio	0.1 (diamond)[7]
Mohs haurdness	10 (diamond) 1-2 (graphite)
CAS Nummer	7440-44-0
History
Diskivery	Egyptians an Sumerians[9] (3750 BC)
Recognized as an element bi	Antoine Lavoisier[10] (1789)
Main isotopes o carbon
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct 11C syn 20 min β+ 11B 12C 98.9% stable 13C 1.1% stable 14C trace 5730 y β− 14N
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Thare are several allotropes o caurbon o which the baist kent are graphite, diamond, an amorphous caurbon.^[16] The pheesical properties o caurbon vary widely wi the allotropic furm. For example, diamond is heichly transparent, while graphite is opaque an black. Diamond is the hairdest naiturally-occurrin material kent, while graphite is saft enough tae furm a streak on paper (hence its name, frae the Greek wird "γράφω" which means "tae write"). Diamond haes a very law electrical conductivity, while graphite is a very guid conductor. Unner normal condeetions, diamond, caurbon nanotube an graphene hae the heichest thermal conductivities o aw kent materials.

Aw caurbon allotropes are solits unner normal condeetions wi graphite bein the maist thermodynamically stable furm. Thay are chemically resistant an require heich temperatur tae react even wi oxygen. The maist common oxidation state o caurbon in inorganic compounds is +4, while +2 is foond in caurbon monoxide an ither transeetion metal carbonyl complexes. The lairgest soorces o inorganic caurbon are limestanes, dolomites an caurbon dioxide, but signeeficant quantities occur in organic deposits o coal, peat, ile an methane clathrates. Caurbon furms mair compoonds than ony ither element, wi almaist ten million pure organic compoonds describit tae date, which in turn are a tiny fraction o sic compoonds that are theoretically possible unner staundart condeetions.^[17]

Caurbon is the 15t maist abundant element in the Yird's crust, an the fowert maist abundant element in the universe bi mass efter hydrogen, helium, an oxygen. It is present in aw kent life furms, an in the human bouk caurbon is the seicont maist abundant element bi mass (aboot 18.5%) efter oxygen.^[18] This abundance, thegither wi the unique diversity o organic compoonds an thair unuisual polymer-furmin ability at the temperaturs commonly encoontered on Yird, mak this element the chemical basis o aw kent life.