Organic Chemistry/Foundational concepts of organic chemistry/Nomenclature

From Wikibooks, open books for an open world
< Organic Chemistry‎ | Foundational concepts of organic chemistry
Jump to: navigation, search

< Acids and bases



Organic Chemistry Nomenclature[edit]

Nomenclature means a system of naming. In organic chemistry, naming can be difficult to get a good handle on. Many chemicals were named before a systematic approach was designed and those names are often called the "common names". A great deal of the basics of modern organic chemistry began to be systemized in the latter half of the 19th century and continued into the early 20th century. Chemists often offered different systems of naming and sometimes one outlasted the other and sometimes a mix of the two came into to use. This has lead to a variety of unusual names and often multiple names for the same thing. While many naming conventions in organic chemistry are derived from Greek, some are derived from Latin. And sometimes a mix is used. For example, many organic molecules are named based on the number of carbons in the chain. From one to ten, those prefixes are meth-, eth-, prop-, but-, pent-, hex-, hept-, oct-, non-, dec-. The first 4 are from common usage prior to any systemic naming. pent- through oct- and dec-, all derive from Greek numbers, and non- derives from the Latin number for nine.

The current standard in naming in organic chemistry is called the IUPAC nomenclature. IUPAC is the International Union of Pure and Applied Chemistry and IUPAC has come up with a standard naming convention for all compounds. As there are millions of known organic molecules and many varieties of piecing them all together, one can imagine that the rules are many and complex.

This tome of naming is the IUPAC Gold Book. When describing naming procedures, this book will often provide simpler rules of naming that don't include all of the exceptions to the rules. We may not discuss all of the possible variations of names, but will more often than not, provide the most common naming methods. These procedures will generally hold you in good stead for almost all situations. When in doubt, however, you will need to consult the Gold Book. This really becomes more important when you're publishing papers in chemistry and you're sharing the information with a wide audience.

Besides legacy names from the early days of chemistry, there are also some variations within the IUPAC naming that can allow a compound to have more than one possible name. You'll witness that in this book where two identical compounds may have two different, but equal names. This variation is provided to give the reader the opportunity to see and become accustomed to the variation. It is weighed against the confusion it causes but as a student of chemistry, you must learn the language, even when that language is sometimes confusing.



<< Foundational concepts | < Acids and bases | Nomenclature | Alkanes >>