Inorganic compound
Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation.[3] All allotropes (structurally different pure forms of an element) and some simple carbon compounds are often considered inorganic.Examples include the allotropes of carbon (graphite, diamond, buckminsterfullerene, graphene, etc.Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern organic chemistry.[4][5][6] In Wöhler's era, there was widespread belief that organic compounds were characterized by a vital spirit.