The molecular formula

After the brief introductory example in the previous chapter, we are now going to explain in more detail the main procedures of MOLGEN with the aid of a large family of isomers. For this purpose, we consider the molecular formula C₈H₁₆O₂. The molecular formula is the first and main piece of input to MOLGEN. It comprises the following notions:

• The atom type, by which we mean the chemical element the atom belongs to. It is entered by the symbol that is also used in the periodic table of elements.
• The multiplicity of an atom, by which we mean the number of atoms of this element contained in the molecular formula in question.
• The valence of an atom, by which we mean the total number of covalent bonds that connect the atom in question with other atoms of the molecule (a double bond requires at least valence 2). So the valence is the number of valence electrons (in the case of hydrogen there is exactly one of them) or the number of missing electrons if we compare the atom in question with the configuration of inert gas (octet).