It has long been accepted in the chemistry of the composition of any material to write in short, with the help of symbols and codes (digits).Recording in this form is known as "empirical" formula.For example, the composition of the phosphoric acid is reflected in this form - H3PO4.From this recording, that phosphoric acid molecule consists of three hydrogen atoms, one - phosphorus and four - oxygen.However, it is unclear how the elements are connected to each other, ie,information is incomplete.To eliminate this gap, the structural formula of the substance used.
This compound has a great record of the information content, asusing it is shown schematically how and in what order the elements of matter are interconnected.In addition, each covalent bond (pair of electrons) is represented by the dash and corresponds to one unit of valence.
example, oxygen has a valence of two, it is surrounded by two lines, the hydrogen - valence of one, therefore, one dash, phosphorus - five, five dashes.On the basis of this writing, it can be assumed chemical properties of substances, they classify and organize.
structural formula can be recorded in full and abridged form.When deployed records indicate all the bonds between atoms, and in writing in an abridged form - is not.
most obvious and important is a graphic representation of the compounds in organic chemistry.After all, the properties of substances depend not only on the number of atoms and molecules, but also the order of their connection.This phenomenon is called "isomer" (branching of the carbon chain).
example, ethane structural formula indicates that all the valences at carbon busy, and he can not attach itself to other atoms.This shows that the C2H6 - Representative saturated hydrocarbons, covalent bond in the molecule, the free electrons have thus only possible for ethane substitution reactions and combustion.
structural formula substances also indicates the functional groups of carbohydrates: an alkyl group - from alcohol, aldehyde - aldehydes, benzene nucleus - from aromatic compounds.In addition, with the help of the schematic images easily "seen" by the presence of characteristic bonds saturated hydrocarbons - single covalent bond.Unsaturated: ethylene - one double bond, diene - two double bonds, triple - acetylene.
Fructose structural formula is an example of spatial isomerism.This carbohydrate has the same qualitative and quantitative composition as glucose.The solution comes in several forms.From graphic formula fructose seen that it comprises a ketone and a hydroxyl group, i.e.the substance has a "dual" properties of alcohols and ketones.Also, this formula allows us to establish that this ketonospirt formed remains cyclical and glucose and pentose sugars (fructose).
Thus, the structural formula of - a graphical representation of a substance with which to identify the location of the atoms in the molecule based on the type of communication and their characteristics.
