Per Torbo's scientific contributions

... Although not quite as widely relevant from a geological perspective, the sulphide mineral pyrrhotite (Fe1-xS) also has the potential to preserve a valuable palaeomagnetic signal [6][7][8], including for meteorites and the crust of Mars [9,10]. However, it has an even more remarkable diversity of magnetic properties over a narrow composition range (0 < x ≤ 0.125) due to the fact that small changes in iron content lead to a variety of superstructures associated with ordering of vacancies on the cation site [11][12][13][14][15][16]. There is a uniform Néel temperature of ~590 K across the pyrrhotite solid solution, Fe1-xS with 0 < x ≤ 0.125, [12,14] above which the structure is hexagonal with the space group P63/mmc (NiAs structure). ...

Reference:

Magnetoelastic properties and behaviour of 4C pyrrhotite, Fe7S8, through the Besnus transition

... Furthermore, the vanadium compound with the atomic structure very close to that of γ*-V 2 O 5 was experimentally found before. This is the mixed oxide of vanadium and molybdenum crystallized as monoclinic C2 (5) (V 0.7 , Mo 0.3 ) 2 O 5 [28]. The difference between the structure of this mixed oxide and that corresponding to C2/m is minor. ...

Reference:

Theoretical study of α- and γ-V2O5 double-walled nanotubes