inert pair effect. This effect is also observed in groups , and . . .
Allotropism in p-block elements: Some elements exist in more than one crystalline or molecular forms in the same physical state. For example, carbon exists as diamond and graphite. This phenomenon is called allotropism (in greek 'allos' means another and ' trope' means change) and the different forms of an element are called allotropes. Many p-block elements show allotropism and some of the common allotropes are listed in the table.
- - - - Table . : Some of common allotropes of p-block elements Element Most common allotropes Boron Amorphous boron, α-rhombohedral boron, β-rhombohedral boron, γ-orthorhombic boron, α-tetragonal boron, β-tetragonal boron Carbon Diamond, Graphite, Graphene, Fullerenes, Carbon nanotubes Silicon Amorphous silicon, crystalline silicon Germanium α-germanium, β-germanium Tin Grey tin, white tin, rhombic tin, sigma tin Phosphorus White phosphorus, Red phosphorus, Scarlet phosphorus, Violet phosphorus, Black phosphorus. Arsenic Yellow arsenic, grey arsenic & Black arsenic Anitimony Blue-white antimony, Yellow, Black Oxygen Dioxygen, ozone Sulphur Rhombus sulphur, monoclinic sulphur Selenium Red selenium, Grey selenium, Black selenium, Monoclinic selenium, Tellurium Amorphous & Crystalline