structural isomerism

Configurational isomerism

Conformational isomerism

Low melting point, boiling point, high volatility; mostly gas, liquid or low melting point solid at room temperature Body (mp. < 400℃)

Poor water solubility, most organic compounds are poorly soluble in water ;Low molecular weight alcohols, aldehydes and ketones, Carboxylic acids, amino acids, and sugar compounds are easily soluble in water

Most can burn to produce CO2 and H2O, such as gasoline, alcohol, etc., but there are exceptions, such as CCl4 is a fire extinguishing agent

Poor thermal stability and easy to decompose when heated (200~300℃)

The reaction speed is slow, the reaction is complex, there are many side reactions, and the yield is low.

Alicyclic compounds

aromatic compounds

Electrons with opposite spin directions pair up to form a covalent bond

Covalent bonds are saturated

Covalent bonds are directional

Molecular orbital theory explained

◼It is to study the motion state of each electron in the molecule from the perspective of the molecule as a whole; ◼The electrons in the chemical bond formed move throughout the molecule (delocalized); ◼Through the solution of Schrödinger equation, the state of electron motion describing the molecules can be obtained The wave functions ψ, ψ are called molecular orbitals; ◼Each molecular orbital ψ has a corresponding energy E, and E is approximately expressed in this The ionization energy of electrons in orbit.

core

Definition: Two atomic orbitals overlap in a "head-to-head" manner along the bond axis, forming a common The valence bond is a σ bond.

Features: The overlapping portion of the orbit is on the line connecting the two cores, cylindrically symmetrical along the bond axis,  bond High energy and stability

Two atomic orbitals are parallel to each other or "side by side" along the vertical internuclear line in the direction of the bond axis. Shoulders" overlap with the same sign, and the covalent bond formed is called a π bond

The average distance between two bonded nuclei

When three or more atoms are bonded, the angle between two covalent bonds

It is the energy released when a chemical bond is formed, or the energy absorbed when a chemical bond is broken. It can be used to mark chemical bonds. Strength of

Covalent bonds formed by different atoms have polarity, represented by dipole moments

recrystallization

distillation

sublimation

chromatography

Ion exchange method

The way and order in which atoms in a molecule are interconnected

On the basis of the structural formula, the spatial arrangement of atoms in a molecule

Different arrangements of molecules in space due to rotation around single bonds

chemical method

physical method

Proposed by Kekule (Germany) and Cooper (English) in 1858

In 1861 Butrelov (Russia) proposed the concept of chemical structure

In 1865, Kekulé proposed the structural formula of benzene

In 1874 Van't Hoff (Netherlands) and Lebel proposed: Carbon Tetrahedral structure; concept of enantiomerism

In 1885, Bayer proposed the tension theory of cyclic compounds.

In the early 20th century, the valence bond theory was established

In the 1930s, quantum chemistry was established and the microstructure of chemical bonds was proposed. Looking at the essence, theories such as induction effect, conjugation effect, and resonance theory appear

In the 1960s, Hoffman proposed the principle of conservation of molecular orbitals

In 1806, Berzelius J (Sweden) first used the term "organic chemistry" in his textbooks. noun

1848 L. Gmelin (Gmelin, Germany): Organic compounds are defined as carbon-containing compounds

More than ten years later, C. Schorlemmer (Schorlemmer, Germany): Organic compounds are hydrocarbons and their derivatives biology

In addition to C and H, organic compounds also contain a few elements such as O, N, S, P, and halogens.

Carbon and simple carbon compounds, such as CO, CO2, CS2, HCN, etc. are still traditionally classified as inorganic compounds.

Study the sources, preparation, structure, properties, applications of organic compounds, as well as related theories, change rules and methods The science of law.

Main research contents of organic chemistry