Energy & Green Tech

How will we achieve carbon-neutral flight in future?

Carbon-neutral aviation is possible, but in future, aircraft are likely to continue to be powered by fossil fuels. The CO2 they emit must be systematically stored underground. This is the most economical of various approaches ...

Energy & Green Tech

Can sodium-ion batteries replace trusty lithium-ion ones?

Sodium-ion batteries are a potential replacement for lithium batteries, but the anodes—positively charged electrodes—that work well for lithium-ion batteries don't provide the same level of performance for sodium-ion ...

Energy & Green Tech

Why we need green hydrogen

Green hydrogen has been in the news often lately. President-elect Biden has promised to use renewable energy to produce green hydrogen that costs less than natural gas. The Department of Energy is putting up to $100 million ...

Electronics & Semiconductors

A better pen-and-ink system for drawing flexible circuits

Conductive ink is a great tool for printing flexible electronic circuits on surfaces. But these inks can be costly, they do not work on some materials, and devices to apply them can plug up. Now, scientists report in ACS ...

Energy & Green Tech

Sustainable biodiesel from neem tree trans-esterification

The neem tree, Azadirachta indica, also known as the Indian Lilac, is well known for its oil extracted from its seed and fruit. It has been used in traditional medicine but has also been investigated for the pest control ...

Energy & Green Tech

New York State can achieve 2050 carbon goals: Here's how

By delving into scientific, technological, environmental and economic data, Cornell University engineering researchers examined whether New York could achieve a statewide carbon-free economy by 2050. Their finding: Yes, New ...

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Carbon (pronounced /ˈkɑrbən/) is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5730 years. Carbon is one of the few elements known since antiquity. The name "carbon" comes from Latin language carbo, coal, and, in some Romance and Slavic languages, the word carbon can refer both to the element and to coal.

There are several allotropes of carbon of which the best known are graphite, diamond, and amorphous carbon. The physical properties of carbon vary widely with the allotropic form. For example, diamond is highly transparent, while graphite is opaque and black. Diamond is among the hardest materials known, while graphite is soft enough to form a streak on paper (hence its name, from the Greek word "to write"). Diamond has a very low electrical conductivity, while graphite is a very good conductor. Under normal conditions, diamond has the highest thermal conductivity of all known materials. All the allotropic forms are solids under normal conditions but graphite is the most thermodynamically stable.

All forms of carbon are highly stable, requiring 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 other 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 more compounds than any other element, with almost ten million pure organic compounds described to date, which in turn are a tiny fraction of such compounds that are theoretically possible under standard conditions.

Carbon is one of the least abundant elements in the Earth's crust, but the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known lifeforms, and in the human body carbon is the second most abundant element by mass (about 18.5%) after oxygen. This abundance, together with the unique diversity of organic compounds and their unusual polymer-forming ability at the temperatures commonly encountered on Earth, make this element the chemical basis of all known life.

This text uses material from Wikipedia, licensed under CC BY-SA