Distributions of transition metal ions in the Mantle

6 Crystal field spectra of low-spin Fe2 in Mantle minerals 

Inversion of phase relationships induced by spin-pairing in Fe2+ ions provides one mechanism for possibly enriching this transition element in the Lower Mantle. Other, more general mechanisms influencing element fractionations, are the effects of pressure on relative sizes, crystal field stabilization energies, bond-types and oxidation states of the cations. 

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