Question

A new allotropic form of cerium due to its transitionunder pressure to the tetravalent state*

Answer 1

Explanation:

" A new allotropic form of cerium due to its transition under pressure to the tetravalent state "

An x-ray structural analysis on cerium under pressure was made in order to investigate its valence behavior in the metallic state.

A new form, α'-Ce, always fcc but strongly collapsed, was found to exist at pressures higher than 50 kbar.

It was deduced that Ce is tetravalent in the α' form.

The atomic radius of CeIV was calculated, and the probable values of the valency in γ-Ce and α-Ce are also estimated.

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