Difference Between IUPAC and Common Names

Key Difference – IUPAC vs Common Names 


Naming chemical compounds is very important to ensure that spoken or written chemical names leave no confusion, and a single name should refer to one substance only. IUPAC names follow an internationally accepted set of rules, and all the chemical compounds get a name according to those rules. In contrast, common names can be any name that does not have common rules. Some of IUPAC names are very difficult to remember, and it is very important to memorize few basic rules in naming chemical compounds. People are more familiar with common chemical names than their IUPAC names since most of the common names are easy to remember, and they do not contain digits, prefixes, and suffixes. This is the key difference between IUPAC and Common Names.

What is IUPAC Name?

The IUPAC names are the internationally accepted method of naming chemical compounds. In general, it can be further divided into two main categories; inorganic compounds and organic compounds. No matter how many branches and how long the molecular structure is; IUPAC names can be used to name any range of molecules. But, it is really difficult to name chemical compounds accurately, without having the proper knowledge about these rules.

Ke Difference - IUPAC vs Common Names

CaCO3 – Calcium Carbonate

What is Common Name of Chemical Compounds?

The common names of chemical compounds do not follow special types of rules as in IUPAC names. In general, common names are easy to remember and convenient to use since the naming method does not consider the magnitude of the molecule, functional groups, or the molecular composition. In some occasions, some chemicals have a single name for their common name and for the IUPAC name.

Difference Between IUPAC and Common Names

CaCO3 – Limestone

What is the difference between IUPAC and Common Names?


IUPAC Names: Every chemical compound gets a name according to the IUPAC nomenclature.  The IUPAC name is directly related to its chemical structure. In other words, IUPAC names consider the functional groups, side chains, and other special bonding patterns in the molecule,


Difference Between IUPAC and Common Names_1

In some molecules, IUPAC names consider the positions where functional groups are located in the molecule.

Difference Between IUPAC and Common Names_2Common Names: Some chemical compounds do not have common names.Some common names are independent from their structure.


  • HCOOH – formic acid
  • HCHO – formaldehyde
  • C6H6 – Benzene
  • CH3COOH – acetic acid

Common names do not consider positions where functional groups are attached.

Difference Between IUPAC and Common Names_3


Inorganic Compounds:

Formula IUPAC Name Common Name
NaHCO3sodium bicarbonate                        sodium hydrogen carbonate baking soda
NaBO3 sodium perborate bleach (solid)
Na2B4O7.10 H2O sodium tetraborate,decahydrate Borax
MgSO4.7 H2O magnesium sulfate heptahydrate Epsom salt
CF2Cl2 dichlorodifluoromethane Freon
PbS lead (II) sulfide galena
CaSO4.2 H2O calcium sulfate dihydrate gypsum
Na2S2O3 sodium thiosulfate hypo
N2O dinitrogen oxide laughing gas
CaO calcium oxide lime
CaCO3 calcium carbonate limestone
NaOH sodium hydroxide lye
Mg(OH)2 magnesium hydroxide milk of magnesia
SiO2 silicon dioxide quartz
NaCl sodium chloride salt

Organic Compounds:

Formula IUPAC Name Common Name
CH3-CH=CH-CH3 2-butene Symbutane
CH3-CH(OH)-CH3 2-propanol or propan-2-ol iso-propyl alcohol
CH3-CH2-O-CH2-CH3 Ethoxy ethane Diethyl ether
HCOOH Methanoic acid Formic acid
CH3COOH Ethanoic acid Acetic Acid
CH3-CO-OCH2-CH3 Ethyl ethanoate Ethyl acetate
H-CO-NH2 Methanamide Formamide


Image Courtesy:

1. Calcium Carbonate By Edgar181 (Own work) [Public domain], via Wikimedia Commons

2. A seashell is largely made of Calcium Carbonate By Hi-Res Images of Chemical Elements [CC BY 3.0], via Wikimedia Commons