Molecular Formula

Molecular formula is made of the chemical symbols of constituent elements, which is followed by numeric subscripts that describe the total number of atoms of each element of a molecule. The molecular formulas are easy to understand and compact, the only factor they lack is the information regarding the atomic arrangement and bonding that is present in the structural formula. The exact number and type of atoms present in a singular molecule of a compound is given by molecular formula. The elements that constitute a molecule with number of atoms present in each element of each molecule is given as a subscript that is followed by symbol of the element. Information’s like proportionality of atoms making a specific chemical compound is expressed by a single line of chemical element numbers and symbols. Often, other symbols are used in representation of compounds molecular formula like dashes, brackets, parentheses, minus ( - ) and plus ( + ) signs.

Organic compounds have hydrogen and carbon listed as the first element of the molecular formula, that is followed by other remaining elements written in alphabetic order. Example is given like, in case of butane, the molecular formula is C₄H_10. Ionic compounds have cation preceding the anion for a molecular formula like, the molecular formula for an ionic compound sodium fluoride is NaF. Molecular formula is not the chemical name of a compound, and does not contain any words. This is entirely different from the structural formula, which has a full chemical structure formula whereas molecular formula may imply certain simplified chemical structures.

The indication of a simple number of each atom present in a molecule. Molecular formula and empirical formula are same for a molecule consisting of one particular type of atom. Molecular formula of a compound helps in determining the molecule whether it is a ternary compound, binary compound or quaternary compound. The expression of number of atoms of each elements in one molecule of a compound is termed as molecular formula. The molecular formula is calculated using the empirical formula if the molar mass value of a compound is known.

n = molar mass/mass of the empirical formula = number of empirical formula unit.

The molecular formula is derived by multiplying the percent composition by the molecular weight, after that each value is divided by the molecular weight, these values are rounded off to the closest whole number.

The list of various compound names and molecular formulas are presented below.

Acetic Acid = CH3COOH

Hydrochloric Acid = HCl

Sulfuric Acid = H2SO4

Acetate = CH3COO-

Ammonia = NH3

Nitric Acid = HNO3

Phosphoric Acid = H3PO4

Sodium Phosphate = Na3PO4

Calcium Carbonate = CaCO3

Ammonium sulfate = (NH4)2SO4

Carbonic Acid = H2CO3

Sodium bicarbonate = NaHCO3

Sodium hydroxide = NaOH

Calcium hydroxide = Ca(OH)2

Ethanol = C2H5OH

Hydrobromic acid = HBr

Sulfuric acid = H2SO4

Nitrous acid = HNO2

Potassium hydroxide = KOH

Silver nitrate = AgNO3

Sodium carbonate = NA2CO3

Sodium chloride = NaCl

Cellulose = (C6H10O5)n

Magnesium hydroxide = Mg(OH)2

Methane = CH4

Nitrogen dioxide = NO2

Potassium hydroxide = KOH

Sodium nitrate = NaNO3

Sulfurous acid = H2SO3

Aluminium sulfate = Al2(SO4)3

Aluminium oxide = Al2O3

Ammonia = NH3

Ammonium nitrate = NH4NO3

Ammonium phosphate = (NH4)3PO4

Barium hydroxide = Ba(OH)2

Carbon tetrachloride = CCl4

Citric acid = C6H8O7

Hydrocyanic acid = HCN

Salicylic Acid = C7H6O3

Hydroiodic acid = Hl

Hypochlorous acid = HClO

Iron iii oxide = Fe2O3

Magnesium phosphate = Mg3(PO4)2

Sodium acetate = NA2SO4

Sucrose = C12H22O11

Potassium nitrate = KNO3

Ammonium bicarbonate = NH4HCO3

Ammonium chloride = NH4Cl

Ammonium hydroxide = NH4OH

Calcium nitrate = Ca(NO3)2

Calcium oxide = CaO

Carbon monoxide = CO

Chlorine gas = Cl2

Phenol = C6H6O

Hydrogen peroxide = H2O2

Hydroxide = OH-

Magnesium chloride = MgCl2

Magnesium hydroxide = Mg(OH)2

Potassium chloride = KCl

Potassium iodide = Kl

Sulfur dioxide = SO2

Glycerin = C3H8O3

Ammonium sulfate = (NH4)2SO4

Barium nitrate = Ba(NO3)2

Calcium acetate = C4H6O4Ca

Sulfurous Acid = H2SO3

Iron oxide = Fe2O3

Potassium carbonate = K2CO3

Silver chloride = AgCl

Sodium iodide = Nal

Sodium oxide = NA2O

Sodium sulfide = Na2S

Sucrose = C12H22O11

Zinc nitrate = Zn(NO3)2

Aluminium Sulfate = AL2(SO4)2

Phenolphthalein = C20H1404

Magnesium nitrate = Mg(NO3)2

Silicon dioxide = SiO2

Acetone = C3H6O

Hydroquinone = C6H6O2

Pyridine = C5H5N

Ammonium acetate = C2H3O2NH4

Xylene = C8H10

Barium sulfate = BaSO4

Benzene = C6H6

Bicarbonate = CHO3-

Chromate = CrO42-

Methyl Ethyl Ketone = C4H8O

Cyanide = CN-

Trichloroacetic acid = C2HCl3O2

Magnesium sulfate = MgSO4

Methanol = CH3OH

Nitrogen dioxide = NO2

Oxygen = O

Methylene blue = C6H18ClN3S

Sodium sulfite = Na2SO3

Sulfur trioxide = SO3

Aluminium phosphate = AlPO4

Stearic Acid = C18H36O2

The structural formula in a compound provides same type of information, just like the molecular formula but it also includes the connection  of atoms in the molecule. For example, structural formula of methane has symbols of one C atom, and four H atoms, which indicates the number of molecules in the atom. There are connecting lines between the atoms to show the structure of bonding holding the atoms together to form the molecules. The identification of molecular formula from the structural formula of a compound is easy and does not involve much work. The significant factor, which must be kept in mind is that the structural formula is similar to the molecular formula, but includes the connecting lines showing the connection of each atom in the molecule of a compound. The structural formula also depicts the bonding of atoms, whether the bonding is single, or double or triple covalent bonding. These covalent bonds in a structural formula are represented in the form of lines, the dashes indicate whether the bond is single, double or triple. Thus, the derivation of molecular formula from the structural formula involves removing the connecting lines, which is a pictorial representation of the bonding occurring between the atoms of a molecule, hence the derivation of molecular formula from structural formula is an easy process.