Why are connections formed from elements

As chemical compound one describes a substance that consists of two or more different chemical elements which - in contrast to mixtures, solutions and alloys - have a fixed atomic and therefore also mass ratio to one another. The characteristic is the chemical formula with which, using the molar mass, for example, the amount of products of a chemical reaction can be calculated (in stoichiometry, with the help of a reaction scheme).

Types of chemical compounds

A rough distinction is made between the more than 17 million known chemical compounds ionic, d. H. salt-like compounds as well as complexes, metallic as molecular Links. Also the subdivision inorganic / organic is fundamental, whereby the carbon compounds are referred to as “organic” (with a few exceptions). So basically there are four types of chemical compounds between the atoms of the elements:

Molecular Connections


  • Molecular Connections arise from non-metal and non-metal - they are non-conductors (insulators) with mostly relatively low boiling points (with the exception of diamond-like or plastic-like compounds with giant molecules). In addition to water, examples of molecular compounds are methane gas, sugar, carbonic acid, polyethylene, etc.

Ionic compounds


  • Ionic compounds (Salts) consist of cations and anions. They are often salty: brittle, with a high melting point and only electrically conductive in melt or solution. Examples of ionic compounds are iron (III) oxide (similar to rust), pyrite (iron sulfide) and sodium chloride (table salt).

Intermetallic compound

Intermetallic compound are made of metal and metal - they are:

  • electrically conductive,
  • easily deformable,
  • shiny and
  • good heat conductor.



  • Higher Order Connections (Complexes) usually arise from a complex formation reaction from non-ferrous metal cations and molecules with free electron pairs (ligands). They are often brightly colored.

Examples: The red blood pigment hemoglobin from iron-II-ions and protein molecules and the deep blue copper-tetrammine complex from copper-II-ions and ammonia).

See also

Categories: Chemical Compound | chemistry