Explain the following with suitable examples: (i) Ferromagnetism (ii)Paramagnetism (iii)Ferrimagnetism (iv)Antiferromagnetism (v)12–16 and 13–15 group compounds.

Q 26:

Explain the following with suitable examples:

(i) Ferromagnetism

(ii)Paramagnetism

(iii)Ferrimagnetism

(iv)Antiferromagnetism

(v)12–16 and 13–15 group compounds.

Solution:

(i) Ferromagnetism:–

Ferromagnetism: few substances like iron, cobalt, nickel, gadolinium and CrO₂ are strongly attracted by a magnetic field. Such substances are known as ferromagnetic substances. These substances can be permanently magnetised with the help of strong electrostatic field.  The metal ions of ferromagnetic substances are grouped together into small regions called domains in solid state. So that each domain acts as a tiny magnet. The domains of  un magnetized piece of a ferromagnetic are randomly oriented so that their magnetic moments get cancelled out. When such substance is placed in a magnetic field, all the domains get oriented in the direction of the magnetic field  and a strong magnetic effect is produced. This ordering of domains remains same  even when the magnetic field is removed and the ferromagnetic substance becomes a permanent magnet.

(ii) Paramagnetism :–

few substances like O₂, Cu²⁺, Fe³⁺, Cr³⁺  are weekly attracted by a magnetic field.

These substabces are magnetised in a magnetic field in the same direction. When we remove magnetic field ,they lose their magnetism. paramagnetism is takes place due to presence of one or more unpaired electrons. These unpaired electron are attracted by the magnetic field.

(iii)Ferrimagnetism:

 This effect is observed when the magnetic moments of the domains in the substance are aligned in parallel and anti–parallel directions in unequal numbers. Ferrimagnetic substances are weakly attracted by magnetic field as compared to ferromagnetic substances. Magnetite like Fe₃O₄  and ferrites like MgFe₂O₄ and ZnFe₂O₄ are examples 

of such substances. On heating these substances lose their ferrimagnetism and become paramagnetic.

(IV)Antiferromagnetism:

Antiferromagnetic substances  have domain structure similar to ferromagnetic substance. The domains of antiferromagnetic substance are oppositely oriented and cancel out each other's magnetic moment . Example MnO is a Antiferromagnetic substance.

(V)12–16 and 13–15 group compounds.

The  compounds of 12–16 group are prepared by combining elements of group 12 and group 16. While the compound of 13–15 group compounds are prepared by combining elements of  group 13 and group15. These compounds are covalent and there ionicity depends up the difference in electro negativities of elements which involve in forming of these compounds. These compounds have special electrical and optical properties so that these compounds are used in industries for a variety of applications  

Examples

ZnS, CdS ,CdSe and HgTe are example of 12–16 group compounds

InSb, AIP and GaAs are the example of 13–15 group compounds