Chemicals
For chemistry, a compound (which is wrongly named chemical compound) is a body whose chemical species (molecule, assembly ... ion) is composed of atoms of several different elements. The atoms forming assemblies of chemical compounds are linked by bonds that may be of different kinds.
Summary |
Types of connections
Bonds of several types can meet the atoms in the compounds. They are classified into three broad categories:
- Ionic bonds : These bonds resulting from the loss of one or more valence electrons per atom, and the capture of these electrons with another atom. The first atom becomes positively charged ( cation ) and the second atom becomes negatively charged ( anion ). Such bonds usually established between elements having a difference of electronegativity very high ( 1.7 on the scale Pauling ), that is to say, a metal and a nonmetal. A well known example: the sodium chloride , NaCl.
- Covalent bonds : In this case, the atoms are sharing each one valence electron to create a pair of bonding electrons is shared between these two entities. Related elements in this type of bond have a smaller difference in electronegativity (<1.7 on the Pauling scale) or zero.
- Coordinate covalent bond : In these bonds, the valence electrons for the bond formation, from a single atom. The electron pair liaison coordination comes from an entity called ligand. We call this type of compound complex.
Organic compounds and inorganic
Organic compounds:
Chemical compounds that contain carbon, with the exception of CO, CO 2, CO 32 - and CN -.
Inorganic:
All other compounds not included in the category of organic compounds.
Legislation
Numerous compounds can have positive or negative effects on health or the environment. For this reason, they are subject (production, transport, sale, processing, labeling, waste management, etc..) Specific regulations, including framed by the REACH directive in Europe. In France, Act II Round Table Notes Bibliography
References
External Links
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