[Chemistry Class Notes] on Nitrogen Dioxide Formula Pdf for Exam

Nitrogen dioxide is a chemical compound formed from nitrogen and oxygen. It is one of the many oxides of nitrogen such as nitrogen monoxide, nitrous oxide, etc. The chemical formula of any compound can be either an empirical formula or a molecular formula. An empirical formula is the simplest whole number ratio of atoms in a compound whereas a molecular formula is the one that specifies the number of atoms of each element in one molecule. The empirical and the molecular formula of nitrogen dioxide is NO2 because it specifies the number of each element and also the simplest whole number ratio which is 1:2 for nitrogen vs oxygen in nitrogen dioxide. 

Properties of Nitrogen Dioxide

The chemical formula of nitrogen dioxide is NO2. This nitrogen dioxide formula serves as both the empirical and the molecular formula. Much significant information can be obtained from the nitrogen dioxide chemical formula such as the binding ratios of the two elements, and the molecular weight of the compound which is a combination of the number of atoms of different elements involved in the formation of the compound. Hence, from the nitrogen dioxide chemical formula it is clear that the molecular weight of nitrogen dioxide is around 46 g/mol. The determination of the molecular weight from the molecular formula of nitrogen dioxide is explained as follows:

Molecular Weight of Nitrogen Dioxide

= (Molecular weight of Nitrogen ∗ Number of Nitrogen atoms) + (Molecular weight of Oxygen ∗ Number of Oxygen atoms)

= (14 g/mol ∗ 1) + (16 g/mol ∗ 2)

= 14 + 32

= 46 g/mol

Other significant properties of Nitrogen Dioxide that are not determined by the nitrogen dioxide chemical formula are:

• A reddish-brown gas above 21.2 ⁰C having a pungent smell and an unpleasant odour. Below the given temperature, it is a yellowish brown liquid and exists as a colourless form of nitrogen tetroxide below – 11.2 ⁰C. 

• It exists in a C[_{2v}] point symmetry group which is shown below in the given image:

• From the image, which shows the structural formula of nitrogen dioxide it is clear that it has a resonating double bond structure with the double bond resonating from N-O pair to another. 

• Nitrogen dioxide is paramagnetic in nature because of the unpaired electrons in the oxygen atom that are present in absence of the double bond. 

• The bond length as depicted in the image is 119.7 pm and is consistent with the bond order of one and two. 

• In the gaseous state, nitrogen dioxide preferentially absorbs light in the blue region of the spectrum i.e. wavelengths in between 400 nm to 500 nm. But it is not restricted to this range. It can absorb any wavelengths ranging from the shorter wavelengths of visible light to longer wavelengths in the infrared region. But such absorptions can lead to other reactions such as absorption of light with wavelengths less than 400 nm leads to photolysis of nitrogen dioxide. 

• The lone electron of nitrogen dioxide in between the resonating double bond structures can mean that nitrogen dioxide behaves as a free radical. 

Because of these properties, nitrogen dioxide can behave as an oxidizer because of the weak N-O bond, its usefulness in the conversion of metal oxides to metal nitrates, and the conversion of alkyl and metal iodides to corresponding nitrites. Apart from these, nitrogen dioxide is a poisonous gas and can lead to health effects such as bronchoconstriction, inflammation, reduced immune response and can affect the heart as well.