Allotropes are the different forms of a compound. For example iron has 3 well known allotropes: alpha iron (α) a.k.a. ferrite, gamma iron (γ) a.k.a. austenite, and delta iron (δ). They form depending on temperature and pressure the iron goes to. Another example is diamond and graphite which are both allotropes of carbon.

Iron allotropes: alpha, gamma, delta and at high pressures epsilon .

Carbon has many allotropes. The system of carbon allotropes spans an astounding range. Source: Wikipedia

Yes ofcourse Hydrogen have two allotropes, Ortho hydrogen and para hydrogen. They differ only in having parallel and anti parallel nuclear spins. It was first observed by Heisenberg in 1927. BY RAJESH KUMAR GDC MPM SINDH PAKISTAN

It is one form of Iron Ferrite where the lattice structure is body-centered and more stable than other allotropes (forms).