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Chemical Formula Of Common Compounds

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Chemical formula is a way to describe chemical ratios of atoms that make up a specific chemical compound or molecule in chemistry. Chemical element symbols, numbers, and sometimes other symbols, such as parentheses, dashes, brackets, commas, plus (+), and minus (-) signs, are used to represent the chemical elements, atoms, or ions. A chemical substance that contains atoms from at least two different elements is referred to be a chemical compound. Chemical compounds and molecules both contain many atoms, but unlike chemical compounds, a molecule can just be made up of atoms from the same element.

In this article, we have covered, Definition of Chemical Formula, Importance of Chemical Formula, Types of Chemical Formulae, and others in detail.

What is Chemical Formula?

A chemical formula is a representation of a substance’s molecular composition in terms of the symbols representing the components that make up the molecule. A molecular formula is another name for a chemical formula.

An element’s or a compound’s chemical formula can be used. A chemical formula is a technique of presenting information on the chemical proportions of atoms that make up a chemical compound or molecule using chemical element symbols, numbers, and other symbols like parentheses, dashes, brackets, and commas.

Importance of Chemical Formula

The importance of Chemical Formulas can be understood as,

  • Compound’s name is represented by a formula.
  • Names of all the elements in the molecule are given in formulae.
  • Number of atoms of each element contained in a molecule is given by formulae.
  • One molecule of a compound is represented by a formula.
  • Formulae denote a definite mass of a substance.

Types of Chemical Formulae

There are different types of chemical formulae based on the composition of chemical compounds:

  • Molecular Formula
  • Empirical formula
  • Structural formula

Molecular Formula

Amount of elements in a substance can be determined from its molecular formula. The periodic table’s symbols are used to represent the elements in molecular formulae, and a subscript is used to indicate how many atoms of each element are present in the molecule.


  • Molecular formula of Urea is CH4N2O which gives exact number of constituent atoms (i.e Carbon, Hydrogen and Nitrogen in one Urea molecule
  • Molecular formula of Acetic Acid is CH3COOH
  • Molecular formula of Glucose is C6H12O6

Empirical Formula

Ratio of the elements present in a chemical compound is represented by its empirical formula. Usually, empirical formulas are developed by the evaluation of experimental data.


  • Empirical formula of Urea is CH4N2O
  • Empirical formula of Acetic Acid is CH2O
  • Empirical formula of Glucose is CH2O

Structural Formula

Structural formula of a chemical compound gives understanding of the arrangement of the atoms in the molecule.


Structural formula of Urea is shown below,

Structural Formula of Urea

Structural formula of Acetic Acid is shown below,

Structural formula of Acetic Acid

How to Write Chemical Formula?

A binary compound is composed of two different elements only. Formulae of binary compounds can be written with the help of valencies of elements since both types of atoms forming the compound must lose, gain or share the same number of electrons.

Points to be considered to write the molecular formula

  • Determine the valency of the elements present in the compound.
  • Write the chemical formula such that the sums of the valencies of the two elements are equal. Do this by determining the lowest common multiple of the two valencies.
  • Always place metals first in the formula.

Chemical Formula of Rust

Elements present in Rust are Iron and Oxygen. Then, 


Iron, Fe (26)

Oxygen, O (8)




Lowest common multiple of valencies is 6. Therefore,

Fe = 2 × 3 = 6

O = 3 × 2 = 6

This implies that the chemical formula is Fe2O3

Chemical Formula of Aluminium Oxide

The elements present in Aluminium Oxide are Aluminium and Oxygen. Then, 


Aluminium, Al (13)

Oxygen, O (8)




The lowest common multiple of valencies is 6. Therefore,

Al = 2 × 3 = 6

O = 3 × 2 = 6

This implies that the chemical formula is Al2O3

Chemical Formula of Methane

Elements present in Methane are Carbon and Hydrogen. Then, 

Symbol Carbon, C (6)Hydrogen, H (1)



Lowest common multiple of valencies is 4. Therefore,

C = 1 × 4

H = 4 × 1

This implies that the chemical formula is CH4

Chemical Formula of Sodium Chloride

Elements present in Sodium Chloride are Carbon and Hydrogen. Then, 

Symbol Sodium, Na (11)Chlorine, Cl (17)



Lowest common multiple of valencies is 4. Therefore,

Na = 1

Cl = 1

This implies that the chemical formula is CH4

Chemical Formula of Calcium Oxide

Elements present in Calcium Oxide are Calcium and Oxygen. Then,

Symbol Calcium, Ca (20)Oxygen, O (8)



Lowest common multiple of valencies is 2. Therefore.

Ca = 1 × 2

O = 1 × 2

This implies that the chemical formula is CaO.

Chemical Formula of Some Common Compounds

Chemical Formula of some common compounds are:

Chemical Formula Table

The table given below gives the chemical symbol and molecular weight of some common compounds

Compound Name

Chemical Symbol

Molecular Weight (g/mol)

Acetic acidCH3COOH60.052
Hydrochloric acidHCl36.458
Sulfuric acidH2SO4‎98.072
Nitric acidHNO363.012
Phosphoric acidH3PO497.994
Sodium phosphateNa3PO4119.976
Calcium carbonateCaCO3100.086
Ammonium sulfate(NH4)2SO4132.134
Carbonic acidH2CO362.024
Sodium bicarbonateNaHCO384.0066
Sodium hydroxideNaOH39.997
Calcium hydroxideCa(OH)274.092
Hydrobromic acidHBr80.912
Nitrous acidHNO2‎47.013
Potassium hydroxideKOH56.11
Silver nitrateAgNO3169.872
Sodium carbonateNa2CO3105.988
Sodium chlorideNaCl58.44
Magnesium hydroxideMg(OH)258.319
Nitrogen dioxideNO230.006
Sodium nitrateNaNO384.994
Aluminium sulfateAl2(SO4)3342.15
Aluminium oxideAl2O3101.96
Ammonium nitrateNH4NO380.043
Ammonium phosphate(NH4)3PO4132.056
Barium hydroxideBa(OH)2171.341
Carbon tetrachlorideCCl4153.811
Citric acidC6H8O7192.123
Hydrocyanic acidHCN‎27.026
Salicylic AcidC7H6O3138.121
Hydroiodic acidHI127.91
Hypochlorous acidHClO52.457
Magnesium phosphateMg3(PO4)2262.855
Sodium acetateC2H3NaO282.0343
Sodium sulfateNa2SO4‎142.036
Potassium nitrateKNO3101.102
Ammonium bicarbonateNH4HCO396.086
Ammonium chlorideNH4Cl53.489
Ammonium hydroxideNH4OH35.046
Calcium nitrateCa(NO3)2164.088
Calcium oxideCaO56.0774
Carbon monoxideCO28.01
Hydrogen peroxideH2O234.0147
Magnesium chlorideMgCl295.211
Potassium chlorideKCl74.5513
Potassium iodideKI166.0028
Sulfur dioxideSO264.066
Calcium acetateC4H6O4Ca158.17
Iron oxideFe2O3159.69
Potassium carbonateK2CO3138.205
Silver chlorideAgCl‎143.318
Sodium iodideNaI149.894
Sodium oxideNa2O61.9789
Zinc nitrateZn(NO3)2189.388
Magnesium nitrateMg(NO3)2148.313
Silicon dioxideSiO260.083
Ammonium acetateC2H3O2NH477.083
Methyl Ethyl KetoneC4H8O72.107
Trichloroacetic acidC2HCl3O2163.38
Magnesium sulfateMgSO4120.361
Sodium sulfiteNa2SO3126.043
Sulfur trioxideSO380.057
Aluminium phosphateAlPO4121.951
Dinitrogen monoxideN2O44.013
Potassium dichromateK2Cr2O7294.185
Sodium bromideNaBr102.894
Sodium hypochloriteNaClO74.439
Zinc acetateZn(CH3COO)2(H2O)2183.48
Zinc chlorideZnCl2136.286
Zinc hydroxideZn(OH)299.424
Magnesium carbonateMgCO384.313
Potassium chlorateKClO3122.545
Maleic acidC4H4O4116.072
Potassium chromateCrK2O4194.189
Zinc sulfateZnSO4161.436
Perchloric acidHClO4100.46
Potassium BromideKBr119.002
Chromic acidH2CrO4118.01
Methyl acetateC3H6O274.079
Manganese dioxideMnO286.9368
Lactic acidC3H6O390.078
Lithium hydroxideLiOH23.95
Phosphorus pentachloridePCl5208.24
Potassium oxideK2O94.2 
Monopotassium phosphateKH2PO4136.084
Sodium fluorideNaF41.98817
Sodium nitriteNaNO268.9953
Barium carbonateBaCO3197.34
Calcium IodideCaI2293.887
Lithium oxideLi2O29.88
Potassium PermanganateKMnO4158.034
Silver phosphateAg3PO4418.58
Ammonium bromideNH4Br97.943
Calcium phosphateCa3(PO4)2310.18
Ammonium carbonate(NH4)2CO396.086
Barium chlorideBaCl2208.23
Magnesium iodideMgI2278.1139
Potassium cyanideKCN65.12
Silver oxideAg2O231.735
Sodium chromateNa2CrO4161.97
Sodium peroxideNa2O277.98
Zinc carbonateZnCO3125.388
Zinc phosphateZn3(PO4)2386.11
Zinc sulfideZnS97.474
Boric acidH3BO361.83
Potassium bicarbonateKHCO3100.114
Potassium hypochloriteKClO90.55
Potassium nitriteKNO285.103
Ammonium iodideNH4I144.94
Ammonium nitriteNH4NO264.06
Ammonium oxide(NH4)2O52.0763
Barium bromideBaBr2297.14
Barium iodideBaI2391.136
Dinitrogen trioxideN2O376.01
Ethylene glycolC2H6O262.07
Nickel sulfateNiSO4154.75
Lithium chlorideLiCl42.394
Potassium fluorideKF58.0967
Potassium sulfiteK2SO3158.26
Silver carbonateAg2CO3275.7453
Sodium cyanideNaCN49.0072
Sodium nitrideNa3N82.976
Strontium chlorideSrCl2158.52
Lithium bromideLiBr86.844
Aluminium fluorideAlF383.9767
Barium fluorideBaF2175.34
Copper (II) carbonateCuCO3123.55
Lithium phosphateLi3PO4115.79
Lead IodidePbI2461.01
Lithium iodideLiI133.844
Magnesium oxideMgO40.3044
Sodium dichromateNa2Cr2O7261.97l
Tartaric acidC4H6O6150.087
Zinc iodideZnI2319.22
Aluminum bromideAlBr3266.69
Sodium PercarbonateC2H6Na4O12157.01
Nickel acetateC4H6O4Ni178.797
Copper sulfateCuSO4159.609
Calcium ChlorideCaCl2110.98
Sodium ChlorateNaClO3106.44
Potassium IodateKIO3214.001
Lead AcetatePb(C2H3O2)2325.29
Formic AcidHCOOH46.03
Sulfur HexafluorideSF6146.06
Dinitrogen PentoxideN2O530.07
Phosphorous AcidH3PO382
Aluminium hydroxideAl(OH)378.00
Potassium acetateCH3CO2K98.142
Barium oxideBaO153.326
Copper(I) OxideCu2O143.09
Copper HydroxideCu(OH)297.561
Chromic OxideCr2O3151.9904
Sodium bisulfateNaHSO4120.06
Copper (II) chlorideCuCl2134.45
Mercuric chlorideHgCl2271.52
Tin (II) chlorideSnCl2189.60
Lead (IV) oxidePbO2239.1988

Also, Check

FAQs on Chemical Formula

Define Chemical Formula?

The term chemical formula is used to define the chemical composition of any compound. It tells us about the elements a compound has, it also tells us about the ratio in which these elements combine.

What is Chemical Formula of Ozone?

Chemical formula of ozone is O3. In ozone three oxygen atoms are combined with each other.

What is Chemical Formula of Rust?

Chemical formula of rust is Fe2O3. Its scientific name is Ferric Oxide.

What is Chemical Formula of Baking Soda?

Chemical formula of baking soda is NaHCO3. Its scientific name is sodium bicarbonate.

What is Chemical Formula of Bleaching Powder?

Chemical formula of bleaching powder is CaOCl2. Its scientific name is calcium oxychloride.

What is Chemical Formula of Washing Soda?

Chemical formula of washing soda is NaCO3. Its scientific name is sodium carbonate.

What is Chemical Formula of Calcium Carbonate?

Chemical formula of calcium carbonate is CaCO3. The common name of calcium carbonate is Chalk.

Last Updated : 15 Feb, 2024
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