The subcell is modulated by positional and occupational modulations of the atoms in higher dimensional space along the ⟨100⟩ and ⟨010⟩ directions, which correspond to ideal cubic perovskite directions ⟨11̅0⟩p and ⟨001⟩p, respectively.
The unified superspace model for the structural description of periodically and aperiodically modulated wagnerite is created with occupational and displacive modulations of Mg/Fe atoms, occupational and displacive modulation of F (O) atoms and displacive modulation of the PO4 tetrahedron.
A unified (3+1 -dimensional model includes three major parts: (1) cations: occupational and displacive modulation of Mg/Fe positions; (2) anions: occupational and displacive modulation of F or O (OH); (3+1 -dimensionaldulation of the PO4 tetrahedron.
Modelling the structure of wagnerite, with a (3+1 -dimensional approach in which F/OH is subject to occupational and displacive modulation appears justified, particularly when we compare bonds and coordination polyhedra around M sites.
Moreover, refinement of the few commensurately modulated wagnerite structures, especially with a 7 b (b = 45 Å) or 9 b (b = 57 Å) supercell, with occupational and positional modulation of Mg/Fe/Mn and F/OH, is much more efficient using a superspace approach.
The ability of liquid formaldehyde to cause dermatitis, skin irritation, and immune modulation in occupational and non-occupational settings is well documented.
The allocation of 25 supplementary grants per year does not appear as effective in reducing expected occupational gaps as the re-modulation of all regional training vacancies.
