Table of Contents
What is Carbon?
Carbon is a chemical element that has the symbol C and atomic number 6. It is a nonmetal that is tetravalent, meaning it has four valence electrons, and occurs naturally in several allotropes, including graphite and diamond. Carbon is the 15th most abundant element in the universe and the fourth most abundant element in Earth’s crust. It is an important component of all living things and is the basis of organic chemistry.
Physical Properties of Carbon
Carbon is an element with a wide range of physical properties due to its ability to form various allotropes and bond with other elements. Here are some of the key physical properties of carbon:
- Appearance: Carbon can exist in different forms, ranging from colorless and transparent (diamond) to black and opaque (graphite).
- Density: The density of carbon varies depending on the allotrope. Diamond, with its tightly packed crystal structure, has a density of about 3.5 grams per cubic centimeter (g/cm³). Graphite, which has layers of carbon atoms arranged in a hexagonal lattice, has a lower density of around 2.2 g/cm³.
- Melting and Boiling Points: The melting point of carbon depends on the allotrope. Diamond, being the hardest naturally occurring substance, has an extremely high melting point of around 3,550 degrees Celsius (6,422 degrees Fahrenheit). Graphite has a lower melting point of about 3,370 degrees Celsius (6,098 degrees Fahrenheit). Carbon sublimes (changes from a solid to a gas without passing through a liquid phase) at around 3,825 degrees Celsius (6,917 degrees Fahrenheit).
- Electrical Conductivity: Carbon can exhibit both electrical conductivity and electrical resistance, depending on the allotrope. Graphite is a good conductor of electricity due to its layered structure, which allows for the movement of electrons. On the other hand, diamond is an excellent insulator and does not conduct electricity.
- Thermal Conductivity: Diamond is an exceptional thermal conductor due to its rigid and closely packed lattice structure. It has the highest thermal conductivity of any known material, making it useful for applications where efficient heat transfer is required. Graphite, with its layered structure, also has relatively high thermal conductivity but not as high as diamond.
- Hardness: Diamond is the hardest natural substance, scoring 10 on the Mohs scale of mineral hardness. It is highly resistant to scratching and has exceptional durability. Graphite, on the other hand, is relatively soft and has a slippery feel due to its layered structure.
- Solubility: Carbon is relatively insoluble in common solvents, such as water, ethanol, and non-polar organic solvents. However, it can dissolve in certain molten metals and in supercritical fluids like carbon dioxide.
- Crystal Structure: Diamond has a three-dimensional crystal lattice structure, with each carbon atom bonded to four neighboring carbon atoms in a tetrahedral arrangement. Graphite has a layered crystal structure, with each carbon atom bonded to three neighboring carbon atoms in a trigonal planar arrangement.
These properties make carbon a versatile element with a wide range of applications, from industrial uses to high-tech applications in electronics, materials science, and more.
Differences between Graphite and Diamond:
Graphite is a soft, black, and shiny mineral consisting of carbon atoms arranged in a hexagonal lattice. Diamond is a very hard, colorless, and transparent mineral composed of carbon atoms arranged in a tetrahedral lattice.
The main difference between graphite and diamond is their hardness. Diamond is the hardest mineral on Earth and can only be scratched by other diamonds. Graphite is very soft and can be scratched by a fingernail.
Other differences between graphite and diamond include their color, luster, and density. Diamond is colorless and transparent, while graphite is black and opaque. Diamond has a high luster, while graphite has a low luster. Diamond is denser than graphite.
Chemical Properties of Carbon
Carbon is a very versatile element and has many chemical properties. It is a nonmetal and is found in Group 14 of the periodic table. Carbon is a solid at room temperature, but it can exist as a gas, liquid, or solid. It is the most common element in the universe and is the basis for all life.
Carbon is a very reactive element and can form covalent bonds with many other elements. It can also form ionic bonds with metals. Carbon is amphoteric, meaning it can react with both acids and bases. It is also a good conductor of electricity.
One of the most important properties of carbon is that it can form many different types of molecules. These molecules can have a wide range of properties, depending on the type of atoms that make up the molecule. Some common carbon molecules include carbon dioxide, methane, and diamond.
Carbon Isotopes
The carbon isotope ratio (C-13/C-12) is a measure of the proportion of the carbon-13 isotope to the carbon-12 isotope. The C-13/C-12 ratio is used to determine the origin of carbon sources.
Organic matter that has been derived from plants (e.g. fossil fuels) has a lower C-13/C-12 ratio than inorganic matter. Inorganic matter has a higher C-13/C-12 ratio than organic matter.
The C-13/C-12 ratio can be used to determine the origin of carbon in a sample. Samples with a low C-13/C-12 ratio are likely to be from organic sources, while samples with a high C-13/C-12 ratio are likely to be from inorganic sources.
