Introductory Organic Nomenclature

Alkanes, Alkenes and Alkynes

Alkanes

CnH2n+2

All single bondsSaturated hydrocarbonsAliphatic or cyclic (note: general formula

changes when in ring form)

Alkenes

CnH2n

One double bondunsaturatedAliphatic or cyclic

Alkynes

CnH2n-2

One triple bondunsaturatedAliphatic or cyclic

Naming the chains

Meth One carbon

Eth Two carbons

Prop Three carbons

But Four carbons

Pent Five carbons

Hex Six carbons

Hept Seven carbons

Oct Eight carbons

Non Nine carbons

Dec Ten carbons

PREFIXES

What is this?

How about this one?

Number three?

The same thing?

What if this happens?

SIDE CHAINS

One carbon ---- methylTwo carbons ---- ethylThree carbons ---- propylFour carbons ---- butylHalogens ---- chloro, etc….

SPECIAL RULES ABOUT ALKENES AND ALKYNES

The multiple bond gets priority over side chains

Put the multiple bond in the lowest possible position