Organic Chemistry 101
By John Mclain
Organic chemistry is a branch and specific discipline of chemistry. Organic chemistry deals specifically with the properties, structure, and composition of organic compounds. Organic compounds, by definition, are compounds that contain carbon and hydrogen atoms. It is generally agreed that the science of organic chemistry began in 1828. It is then that Friedrich Woehler accidentally evaporated an aqueous solution and came up with the organic compound called urea.
Although carbon is not the most common element in the world, it is one of the most versatile. Organic compounds are composed of carbon and hydrogen molecules, but may also contain other elements. Some of the most common elements found in organic compounds include oxygen, halogens, nitrogen, and sometimes sulfur or phosphorus.
Most organic compounds are covalently bonded, which allows them to form long, complex carbon chains and rings. Carbon atoms are very stable, and are able to form stable covalent bonds with one another (known as catenation). Unlike non-organic materials, organic compounds will usually melt or decompose if exposed to temperatures below 300 degrees Celsius. Another characteristic of organic compounds is that they tend to be more soluble in organic solvents. Solubility, however, always depends on the overall structure of the compound and the functional groups present. A functional group refers to the parts of a molecule that make up its specific chemical nature.
Perhaps the most important and most studied types of organic compounds are those that contain nitrogen. These compounds usually contain parts of the amino group. When the amino group combines with the carboxyl group, amino acids are born. Amino acids are regarded as the building blocks of proteins.
Scientists and researchers use several types of methods in order to determine the molecular structure of an organic compound. Here are the most common methods currently in use:
Crystallography: Crystallography is the science of determining the arrangements of atoms in solids. By studying the diffraction patterns given off by a sample, scientists are able to determine its structure. This is the most precise method for studying compounds. However, most crystals are not large enough to produce a clear picture of some compounds.
Mass Spectrometry: This method involves examining the molecular weight and fragmentation pattern of a compound to determine its chemical structure.
Elemental Analysis: Elemental analysis involves analyzing the sample of the compound to determine its elemental and isotopic composition. In studying organic compounds mostly destructive methods, such as flame atomic absorption or graphite furnace atomic absorption, are used to determine the elemental composition of a molecule.
Infrared Spectroscopy: Spectroscopy is used to determine the presence or absence of functional groups to learn the chemical nature of a molecule.
UV/VIS Spectroscopy: Ultraviolet-Visible spectrophotometry to determine the nature of a compound. Spectrophotometry uses a spectrophotometer to measure how much light is absorbed by the sample.
Nuclear Magnetic Resonance (NMR): NMR spectroscopy is one of the most common methods to obtain the physical, chemical, structural and electronic nature of a molecule. NMR works by studying the magnetism of a nucleus by placing it in alignment with a magnetic field, and then using an electromagnetic field to disrupt this alignment.