(a) Ferromagnetic: These substances (ferromagnetic substances) are strongly attracted by magnetic fields. They could be permanently magnetized even when a magnetic field is absent. Few examples of ferromagnetic substances include cobalt, iron, nickel, CrO₂ and gadolinium. In a solid state, their metal ions come together to form small regions termed domains and each domain behaves like a tiny magnet. In a magnetized piece of a ferromagnetic substance, these domains are randomly arranged thus, their net magnetic moment becomes zero. However, when it is kept in a magnetic field, the domains orient themselves in the direction of the field. This results in a powerful magnetic effect being produced. This orientation of domains persists even after the field is removed. Hence, the ferromagnetic substance is transformed into a permanent magnet.

(b) Paramagnetism : These substances  (paramagnetic substances) are attracted by a magnetic field but after the removal of the field, they lose their magnetism.

Examples of paramagnetic substances include Cr₃t, O₂, Cu₂t, and Fe₃t. To undergo paramagnetism, a substance must possess one or more unpaired electrons. These unpaired electrons are pulled by the magnetic field, thus causing paramagnetism.

(c) Antiferromagnetism : An antiferromagnetic substance has domain structures similar to that of ferromagnetic substances but in the opposite orientation. These oppositely-oriented domains null out each other’s magnetic moments. Schematic alignment of magnetic moments in antiferromagnetic substances.

(d) Ferrimagnetism: In these substances, the magnetic moments of the domains are oriented in parallel and anti-parallel directions and in unequal numbers. A few examples of ferromagnetic substances include ferrites like MgFe₂O₄ and ZnFe₂O₄, Fe₃O₄ (magnetite), etc. As compared to ferromagnetic substances these substances are weakly attracted by magnetic fields. Upon heating, they become paramagnetic.

(e) 12-16 and 13-15 group compounds: The group 12-16 compounds are obtained by combining together group 16 and group 12 elements. Group 13-15 compounds are obtained by combining group 15 and group 13 elements. These compounds are prepared to stimulate average valence of four as in Si or Ge. Indium (III) antimonide (IrSb), gallium arsenide (GaAS) and aluminium phosphide (AlP) are some typical compounds of groups 13-15.

GaAs semiconductors provide a very minute response time and they have totally changed the designing of semiconductor devices. Few examples of group 12-16 compounds are zinc sulphide (ZnS), mercury (II) telluride (HgTe), cadmium sulphide (CdS) and cadmium selenide (CdSe). The bonds these compounds have are not perfect covalent. Their bond’s ionic character depends upon the electronegativity of the two species/elements.