This article discusses N2O lewis structure and its hybridization, shape, bond angle, and relevant detailed explanations.
N2O is covalent molecule. The central N atom is sp hybridized and terminal N and O are sp, and sp3 hybridized respectively. Being sp hybridization the geometry of Nitrous Oxide is linear. So, the N-N-O bond angle is 1800.
The central N makes one covalent bond with N and O. The molecule is neutral but in resonance, its show different canonical form, and some of them are charged. To complete its octet central N atom may form a π bond with terminal N and O along with a sigma bond. The lone pairs reside over N as well as O. N-N bond makes zero dipole moment but N-O makes resultant dipole moment. So N2O is a polar molecule.Nitrous Oxide (N2O) is also known as dinitrogen monoxide.
Some facts about Nitrous Oxide
The molecular weight of Nitrous Oxide is 44.013 g/mol. The density of N2O is 1.977 g/L. The melting point and boiling point of Nitrous oxide are 182.29 K and 184.67 K respectively. The most common synthesis process of Nitrous Oxide is the thermal decomposition of dry Ammonium Nitrate (NH4NO3).
Nitrous Oxide is often referred to as laughing gas. It is a colorless, non-flammable gas. The odor of the gas is slightly sweet. It acts as a ligand, coordinates with several metal centers and participates in many organometallics reactions.
Method of drawing the Lewis structure for N2O
Before proceeding with the lewis structure of N2O at first, we should know what lewis structure is. Lewis structure or lewis dot structure is one kind of representation of a molecule showing the valence electrons, especially in the covalent bond.
With the help of the lewis structure, we can easily determine the valence electrons, number of electrons participating in bond formation as well as the formal charge of the molecule.
There are some points, we should kept in mind to draw the lewis structure of a molecule.
- First, we need to calculate the valence electrons of every individual atom in the molecule and added together.
- If the molecule is bearing a negative charge then an extra electron equal to the negative charge is added.
- If the molecule is cationic then an equal number of electrons should be removed from the molecule.
- Next, we should identify the central atom by its electronegativity, Normally, a competitively more electropositive atom should be the central atom.
- Now all the atoms in the molecules are connected via a single bond.
- Then lone pairs are assigned to the atom, generally lone pairs are assigned to the electropositive atom.
After assigning the lone pairs if the octet of an atom is not completed then a double or triple bond should be drawn in order to complete the octet. If required the lone pairs should be converted to the bond pairs to satisfy the octet.
In Nitrous oxide, the central N atom is surrounded by one N and one O atom. The electronic configuration of N is 1s22s22p3 and the electronic configuration of O is 1s22s22p4. So taking into consideration the valence shell electron of N is five, among them three electrons form bond with terminal N and O and two of them remain as lone pair.
The valence electron of O is six and two of them form bonds with central N and four of them remain as two pairs of lone pair. For the terminal, one electron forms bond with central n and four of them remain as two pairs of lone pairs. So the total number of valence electrons of N2O is (2*5) + 6 = 16.
N2O lewis structure shape
One lone pair over the central N atom and two pairs of lone pairs over terminal N and O respectively. The structure is linear and the electron density is distributed over the molecule.
N2O lewis structure formal charge
The formal charge is defined as the charge over a particular molecule assuming that all the atoms have the same electronegativity.
F.C. = Nv – Nl.p. -1/2 Nb.p
From resonance the most contributing structure of nitrous oxide is
So we should calculate the formal charge for individual.
F.C. of terminal N = 5-2-(6/2) = 0
F.C. of central N = 5-0-(8/2) = 1
F.C. of terminal O = 6-6-(2/2) = -1
Number of lone pairs in N2O lewis structure
The total number of lone pairs is calculated by the sum of an individual atom’s lone pair. Now we should consider the most stable canonical form according to resonance. The most stable canonical form of Nitrous Oxide is
So, the total number of lone pairs in Nitrous Oxide is (1+3) = 4.
Hybridization of N2O
For calculating hybridization we should consider the most contributing canonical form of Nitrous Oxide. In that form, there will be a triple bond between two N atoms and one single bond between N and O.
It involves the mixing of atomic orbitals having similar energy to form an equal number of mixed orbitals or hybrid orbitals and these hybrid orbitals are so oriented in space that they can overlap with suitable orbitals of the subsequent. If the orbitals are of the same energy is called equivalent hybridization and if the mixed orbitals are of different energy then it is called non- equivalent hybridization.
In the ground state, the electronic configuration of N is [He]2s22p3. We know that the maximum number of electrons occupying in p orbital is 6. To complete the octet N needs 3 more electrons. Again the electronic configuration of O is [He]2s22p4.
To complete octet O need 2 more electrons. So now they will undergo hybridization. For terminal N which makes a triple bond with the central N atom, among them two are π bonds and we should not consider π bond in hybridization. So, In the central N atom, there are two electrons in the s orbital that remain as a lone pair and one electron from the p orbital undergoes hybridization with the central N atom.
So, the hybridization of terminal N atom is sp. For the terminal N atom there is no lone pair, one electron from the p orbital makes a sigma bond with O and one electron from the s orbital makes a sigma bond with terminal N. other electrons make the double and triple bond with terminal n which are not participating in hybridization. So the mode of hybridization of the central N atom is sp.
In terminal O there are three lone pairs and one bond pair (make sigma bond with central N). So, the hybridization of O is sp3.
N2O bond angle
From the hybridization, we know that the central N atom in Nitrous oxide is sp hybridized, so the bond angle of N-N-O is 1800.
Since the terminal O is sp3 hybridized so the shape of the molecule about the terminal O is slightly tilted.
N2O octet rule
According to the octet rule, every atom should complete its valance shell by donating electrons or accepting electrons to gain the nearest noble gas configuration.
Nitrogen is a group of VA elements so it has 5 electrons in its outermost shell and Oxygen is a VIA element so It has 6 electrons in the outermost shell. So, undergoing hybridization there will be new hybrid orbitals form, this way Nitrogen as well as Oxygen complete their octet and gain the nearest noble gas configuration. But there is an excess of the electron over Oxygen so a negative charge resides on Oxygen.
N2O resonance structure
Resonance is a theoretical concept – that introduce to explain the bonding properties of molecules via shifting of the electronic clouds between the atoms in such a way that the main structure of the framework remains unchanged. In fact, it is another bonding model where the actual structure may be represented as the resonance having a hybrid of a number of different canonical forms.
Rules for the most contributing structure
- The most contributing structure should be one that contains the largest number of covalent bonds.
- For more than one structure having an equal number of covalent bonds the one in which more electronegative substituents containing the electronegative charge will have a higher contribution, more electropositive substituents containing the positive charge.
The structure I, II, and III have the highest number of the covalent bond, and hence they will have a higher contribution as compared to that of IV and V. Among I, II, III structure III will have the least contribution since like charges are close to each other. Among structures I and II the former will have a greater contribution since electronegative elements Oxygen contains a negative charge and a positive charge over the lee electronegative atom N.
Uses of N2O
- It is used rocket motor fuel as an oxidizing agent
- It is used in the manufacturing of different semiconductors
- It is used in the medical field as an analgesic and anesthetic and specially used in dentistry
- It is used as a flavoring ingredient
- Also used in an anti-anxiety agent.
Frequently asked questions (FAQ)
Which is more polar between N2O and NO2 ?
N2O is linear and NO2 is bent. So the resultant dipole moment in NO2 is higher than N2O, so NO2 is more polar.