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.

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.

CaCO3 – Limestone
What is the difference between IUPAC and Common Names?
Range:
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,
Examples:
In some molecules, IUPAC names consider the positions where functional groups are located in the molecule.
Common Names: Some chemical compounds do not have common names.Some common names are independent from their structure.
Examples:
- HCOOH – formic acid
- HCHO – formaldehyde
- C6H6 – Benzene
- CH3COOH – acetic acid
Common names do not consider positions where functional groups are attached.
Examples:
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
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