Quick Facts
| Property | Value |
|---|---|
| Symbol | C |
| Atomic Number | 6 |
| Atomic Mass | 12.011 u |
| Category | Nonmetal |
| Period | 2 |
| Group | 14 |
| Block | p |
| Electron Configuration | [He] 2s² 2p² |
Physical Properties
| Property | Value |
|---|---|
| State at 20°C | Solid |
| Density | 2.267 g/cm³ (graphite), 3.513 g/cm³ (diamond) |
| Melting Point | 3550°C (3823 K) sublimes |
| Boiling Point | 4027°C (4300 K) sublimes |
| Appearance | Black (graphite), transparent (diamond) |
Atomic Properties
| Property | Value |
|---|---|
| Electron Configuration | [He] 2s² 2p² |
| Electronegativity | 2.55 (Pauling scale) |
| First Ionization Energy | 1086.5 kJ/mol |
| Atomic Radius | 77 pm |
| Covalent Radius | 76 pm |
| Van der Waals Radius | 170 pm |
History and Discovery
Discovered by: Known since antiquity Year of Discovery: Prehistoric Location: Unknown
Etymology
The name "carbon" comes from the Latin word "carbo" meaning "coal" or "charcoal." Carbon has been known since ancient times in the forms of soot, charcoal, graphite, and diamonds.
Discovery Story
Carbon has been used since prehistoric times. Ancient civilizations used charcoal for smelting metals and creating cave paintings. Diamond and graphite were known in ancient India and China. In 1772, Antoine Lavoisier showed that diamonds are made of carbon by burning them and analyzing the gas produced. In 1779, Carl Wilhelm Scheele demonstrated that graphite was also a form of carbon.
Isotopes
| Isotope | Natural Abundance | Half-life | Decay Mode |
|---|---|---|---|
| ¹²C | 98.93% | Stable | - |
| ¹³C | 1.07% | Stable | - |
| ¹⁴C | Trace | 5,730 years | β⁻ |
Occurrence
Natural Abundance
Carbon is the fourth most abundant element in the universe and the 15th most abundant in Earth's crust (about 200 ppm). It forms the basis of all known life. Carbon exists in various allotropes including diamond, graphite, fullerenes, and graphene. It is found in carbonates, fossil fuels, and all organic matter.
Extraction and Production
- Graphite: Mined directly or synthesized from petroleum coke
- Diamond: Mined from kimberlite pipes or synthesized under high pressure and temperature
- Carbon Black: Produced by incomplete combustion of hydrocarbons
- Activated Carbon: Made by heating carbonaceous materials
Applications and Uses
Industrial Applications
- Steel production (carbon steel, cast iron)
- Carbon black for tires and rubber products
- Graphite electrodes for electric arc furnaces
- Carbon fibers for composites
Technological Applications
- Carbon fiber composites in aerospace and automotive
- Carbon nanotubes and graphene for electronics
- Lithium-ion battery electrodes
- Semiconductors
Chemical Applications
- Base of organic chemistry and petrochemicals
- Carbon dioxide for carbonation and refrigeration
- Activated carbon for filtration and purification
Other Uses
- Diamonds for jewelry and cutting tools
- Pencils (graphite)
- Carbon dating using carbon-14
- Fuel (coal, natural gas, oil)
Biological Role
Carbon is the basis of life on Earth. It forms the backbone of all organic molecules including DNA, proteins, carbohydrates, and lipids.
In the Human Body
- About 18.5% of body mass is carbon
- Forms the structure of all organic molecules
- Essential component of DNA, RNA, and proteins
- Central to metabolism through the carbon cycle
Carbon Cycle
Carbon cycles through the atmosphere, oceans, living organisms, and Earth's crust through processes including photosynthesis, respiration, decomposition, and combustion.
Safety and Hazards
Toxicity
Pure carbon (diamond, graphite) is non-toxic. However, fine carbon particles (like carbon black or coal dust) can cause respiratory issues when inhaled. Carbon monoxide (CO) is extremely toxic.
Handling Precautions
- Avoid inhalation of fine carbon particles
- Coal dust can be explosive
- Carbon monoxide requires detection equipment in enclosed spaces
- Handle carbon fibers with care (can be irritating)
Environmental Impact
Carbon dioxide is a major greenhouse gas contributing to climate change. Fossil fuel burning releases stored carbon into the atmosphere. Carbon sequestration and capture are active areas of research.
Interesting Facts
- Carbon can form more compounds than any other element except hydrogen
- A single carbon nanotube is stronger than steel but much lighter
- Diamond is the hardest natural material; graphite is one of the softest
- The same carbon atoms cycle through living organisms, the atmosphere, and rocks
- Buckminsterfullerene (C₆₀) is shaped like a soccer ball and was named after architect Buckminster Fuller