Full form of C is Carbon

Carbon (Symbol: C, Atomic number: 6) is a non-metallic element known for ages to humankind. It belongs to period 2 and group 14 of the periodic table of elements. It is the 15th most abundant element in the earth’s crust, forming 0.025 percent of it. Carbon, in its various forms, is a common element for all living organisms.

The largest inorganic carbon sources are limestones, dolomites, and carbon dioxide, with significant quantities found in organic deposits of coal, peat, oil, and methane clathrates. Carbon is also known for forming the highest number of compounds and is called the "King of elements". Some common allotropes of carbon are graphite, diamond, and buckminsterfullerene, etc.