Sentence Examples

  • (methylene) groups and the molecule consists of a single chain; such hydrocarbons are referred to as being normal; (2) has a branch and contains the group; CH (methine) in which the free valencies are attached to carbon atoms; such hydrocarbons are termed secondary or iso-; (3) is characterized by a carbon atom linked directly to four other carbon atoms; such hydrocarbons are known as tertiary.
  • It is remarkable that sulphur can replace two methine or CH groups with the production of compounds greatly resembling the original one.
  • Similarly, two or more methine groups may be replaced by the same number of nitrogen atoms with the formation of rings of considerable stability.
  • The three primary members are furfurane, thiophene and pyrrol, each of which contains four methine or CH groups, and an oxygen, sulphur and imido (NH) member respectively; a series of compounds containing selenium is also known.