12.1 Introduction Systems that have a p orbital on an atom adjacent to a double bond---molecules with delocalized pibonds– are called conjugated unsaturated systems
There is a group of compounds in which carbon forms only two bonds. These neutral divalent carbon compounds are called carbenes. Most carbenes are highly unstable compounds that are capable of only fleeting existence. Soon after carbenes are formed they usually react with another molecule
Phenols are like alcohols in being able to form strong intermolecular hydrogen bonds. Phenols have higher boiling points than hydrocarbons of the same molecular weight. A modest solubility in water
More environment-friendly methods Natural insect attractants — instead pesticide Less reactive compounds organic refrigerants and aerosol propellant — instead Freon (that destroy the Earth’s ozone layer) Cars with more efficient combustion engines — reduce the massive amount of automobile
1858 ~ 1861, Kekulé, Couper, and Butlerov, laid the basis for one of the most fundamental theories in chemistry: the structural theory. Valence（化合价）: C — tetravalent; O — divalent; H — monovalent
Three Ways to Describe Crystal Structures Three Structural sketches of P4O10 molecules: (a)Stick-ball model：showing that the P-O chemical bond is the tetrahedral coordination and sp3 covalent bonds
“One should beware of mathematicians and all who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and confine man in the bonds of Hell” St Augustine, Bishop of Hippo, circa 400 A.D “To move things is all that Mankind can do…For such the
