A chemical structure includes molecular geometry, electronic structure and crystal structure of a chemical compound. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together. Molecular geometry can range from the very simple, such as diatomic oxygen or nitrogen molecules, to the very complex, such as protein or DNA molecules. Molecular geometry can be roughly represented using a structural formula. Electronic structure describes the occupation of a compound's molecular orbitals.

[edit] Structure determination

Structural determination in chemistry is the process of determining the chemical structure of chemical compounds. Practically, the end result of such process is the obtainment of the coordinates of the atoms in a molecule.^[1] The methods by which one can determine the structure of a molecule is by various methods of spectroscopy, such as nuclear magnetic resonance (NMR), infrared spectroscopy and Raman spectroscopy, electron microscopy, and x-ray crystallography (x-ray diffraction). The last technique can produce 3D models at atomic resolution, as long as crystals are available, as x-ray diffraction needs numerous copies of the molecule being studied that must also be arranged in an organised way.^[1]

The following are common methods for determining chemical structure:

• X-ray diffraction
• Proton NMR
• Carbon NMR
• Mass spectrometry
• Infrared Spectroscopy

The following are common methods for determining electronic structure:

• Electron-spin resonance
• Cyclic voltammetry
• Electron Absorption Spectroscopy
• X-ray photoelectron spectroscopy

[edit] See also

• Chemical conformation
• Pauli exclusion principle
• Lipinski's Rule of Five, describing molecular properties of drugs
• QSAR, quantitative structure-affinity relationship
• Chemical property
• Molecular property
• Physical property
• Structure determination
• Crystallographic database

[edit] References