Table 4: Position of Raman peak ν2 and half-width (widening - Γ) (cm-1) for well crystallized 1) Intermediate; 2) and disordered todorokite; 3) From Pacific Ocean bottom between 100 and 600 cm-1.

MODE 1 2 3

ν3 High wavenumber stretching Mn-O mode

Half-width (Γ) of 640 cm-1 band

640

10-15

620

20-25

610

> 30-35