Chemistry - Carbon and its Compounds (Allotropes, Carbon Dioxide, Methane)

Allotropy is the phenomenon where an element exists in two or more forms that have different physical properties but identical chemical properties. Carbon exhibits this through crystalline and amorphous forms.

Crystalline allotropes of Carbon include Diamond (hardest natural substance, 3D tetrahedral structure), Graphite (soft, slippery, hexagonal layers, good conductor), and Fullerenes (e.g., $C_{60}$ or Buckminsterfullerene).

Amorphous allotropes of Carbon include Coal, Coke, Charcoal, and Lampblack. They do not have a defined internal geometric structure.

Carbon Dioxide ($CO_2$) is a colorless, odorless gas. It is non-combustible and does not support combustion. It is heavier than air and slightly soluble in water, forming carbonic acid ($H_2CO_3$).

Methane ($CH_4$), commonly known as 'Marsh Gas,' is the simplest hydrocarbon. It is a major component of Natural Gas and Biogas, possessing a tetrahedral molecular geometry.

Tetravalency and Catenation: Carbon has a valency of 4 ($Tetravalency$) and the unique ability to link with other carbon atoms to form long chains or rings ($Catenation$).

Greenhouse Effect: Gases like $CO_2$ and $CH_4$ trap solar heat in the Earth's atmosphere, contributing to global warming.