Ozone - O3

What is Ozone?

Ozone, O3, an unstable, blue, diamagnetic gas with a characteristic pungent odor, protects the earth and its inhabitants from intense ultraviolet radiation from the sun.

Ozone is an allotropic molecular form of oxygen containing three atoms of oxygen (O3). Ozone O3 is generated through the passage of oxygen O2 through a high voltage potential resulting in the attachment and formation of a third oxygen atom. The molecular formula for ozone (O3) was established by Soret (1863) by taking the ratio of the change in volumes when O3/O2 mixtures were either heated or exposed to turpentine and cinnamon oil. The word ‘ozone’ comes from the Greek word ‘ozein’ which means ‘to smell’. This meaning comes from ozone at the ground level, which gives off a pungent, acrid odour.

Other names – Triatomic oxygen

O3 Ozone
Density 2.14 kg/m³
Molecular Weight/ Molar Mass 48 g/mol
Boiling Point -112 °C
Melting Point -192.2 °C
Chemical Formula O3

Ozone Structure – O3


Physical Properties of Ozone – O3

Odour Similar to chlorine
Appearance Pale blue gas
Covalently-Bonded Unit 1
Hydrogen Bond Acceptor 2
Complexity 4.8
Solubility Soluble in water, CCl4, Sulfuric acid

Chemical Properties of Ozone – O3

    • Ozone dissolves in water resulting in the formation of hydrogen peroxide. The chemical equation is given below.

O3 + 3H2O → 3H2O2

    • Ozone reacts with lead sulfide resulting in the formation of lead sulfate. The chemical equation is given below.

3PbS + 4O3 → 3PbSO4

Uses of Ozone – O3

  • Ozone used at water treatment plants without filtration systems.
  • Ozone may also be formed by commonly used equipment such as photocopiers, laser printers, and other electrical devices.
  • In medicine, by limiting the effects of bacteria, viruses, fungi, yeast, and protozoa, ozone therapy is used to disinfect and treat diseases.
  • Several ozone-depleting compounds possess properties that make them good refrigerants that is, they can efficiently transfer heat from one location to another.

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1. What exactly is ozone?
Ozone (O3) is an highly reactive gas that consists of three oxygen atoms. It is both a natural product and a man-made product, found in the upper atmosphere of the Earth. (Stratosphere), and lower (troposphere) atmosphere. Ozone impacts life on Earth in either good or bad ways, depending upon where it is in the atmosphere.

2. Is ozone toxic to breathe?
Ozone can be detrimental to safety, be it in its pure form or combined with other chemicals. Ozone can cause damage to the lungs when inhaled. Relatively low ozone levels can cause pain in the throat, coughing, shortness of breath and inflammation in the lungs.

3. Is ozone a resonance structure?
Ozone, or O3, has two major resonance structures which contribute equally to the molecule’s overall hybrid structure. The two arrangements are similar to the standpoint of equilibrium, each having a positive and negative formal charge on two of the oxygen atoms.

4. How many lone pairs are in Ozone?
In the ozone the Oxygen containing double bond has two lone pairs; oxygen containing positive charge has one lone pair and the oxygen containing negative charge has three lone pairs. So the total six number of lone pairs present in one ozone molecule.

5. Why is ozone bent instead of linear?
Based on the VSEPR (valance shell electron pair repulsion) theory, electrons will repel the electron cloud of the two oxygen atoms on each end. This will result in the end O groups being pushed down giving the O3 molecule a bent molecular geometry or V shape.




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