Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It determines several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism, and biological activity.[1][2] The angles between bonds that an atom forms depend only weakly on the rest of molecule, i.e. they can be understood as approximately local and hence transferable properties.
The specific three dimensional arrangement of atoms in molecules is referred to as molecular geometry. We also define molecular geometry as the positions of the atomic nuclei in a molecule.
There are various instrumental techniques such as X-Ray crystallography and other experimental techniques which can be used to tell us where the atoms are located in a molecule. Using advanced techniques, very complicated structures for proteins, enzymes, DNA, and RNA have been determined. Molecular geometry is associated with the chemistry of vision, smell and odors, taste, drug reactions and enzyme controlled reactions to name a few.
Molecular geometry is associated with the specific orientation of bonding atoms. A careful analysis of electron distributions in orbitals will usually result in correct molecular geometry determinations. In addition, the simple writing of Lewis diagrams can also provide important clues for the determination of molecular geometry.
Molecular geometry, the bond lengths and angles, are determined experimentally. Lewis structures can give us an approximate measure of molecular bonding. There is a simple procedure that allows us to predict overall geometry is the VSEPR, Valence Shell Electron Pair Repulsion. The concept is that valence shell electron pairs are involved in bonding, and that these electron pairs will keep as far away from each other, due to electron-electron repulsion.
DETERMINING MOLECULAR GEOMETRY
The molecular geometry can be determined by various spectroscopic methods and diffraction