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Chemical nomenclature (view source)
Revision as of 16:13, December 18, 2007
, 16:13, December 18, 2007→Molecular Compounds
===Molecular Compounds===
===Molecular Compounds===
The procedures for naming binary (two element) molecular compounds are similar to those for naming ionic compounds. In these molecular compounds it is possible to associate a more positive nature with one element in the molecule and a more negative nature with the other element. The element with the more positive nature is named first and also appears first in the chemical formula. The second element is named with an -ide ending. For example, the name for HCl is hydrogen chloride. (this is the name used when referring to the pure compound; water solutions of HCl are referred to as hydrochloric acid.)
Often a pair of elements can form several different molecular compounds. For example, carbon and oxygen form CO and CO<sub>2</sub>. To distinguish these compounds from one another, the prefixes given below are used to denote the numbers of atoms of each element present.
{| class="wikitable"
|-
! Prefix
! Meaning
|-
| Mono-
| 1
|-
| Di-
| 2
|-
| Tri-
| 3
|-
| Terta-
| 4
|-
| Penta-
| 5
|-
| Hexa-
| 6
|-
| Hepa-
| 7
|-
| Octa-
| 8
|}
Thus CO is called carbon monoxide, and CO<sub>2</sub> is called carbon dioxide. When the prefix ends in ''a'' and the name of the anion begins with a vowel (such as oxide), the ''a'' is often dropped.
==Organic Compounds==
==Organic Compounds==
Organic compounds contain carbon, usually in combination with hydrogen, oxygen, nitrogen, or sulfur. Organic compounds were first associated only with plants and animals. However, a great number of organic compounds have now been prepared that do not occur in nature.
Organic compounds contain carbon, usually in combination with hydrogen, oxygen, nitrogen, or sulfur. Organic compounds were first associated only with plants and animals. However, a great number of organic compounds have now been prepared that do not occur in nature.