Symmetry based properties of the transition metal dichalcogenide nanotubes

The full geometrical symmetry groups (the line groups) of the monolayered, 2Hb and 3R polytypes of the inorganic MoS2 and WS2 micro- and nanotubes of arbitrary chirality are found. This is used to find the coordinates of the representative atoms sufficient to determine completely the geometrical str ucture of the tubes. Then some physical properties which can be deduced fro m the symmetry are discussed: electron band degeneracies, selection rules, general forms of the second rank tensors and potentials, phonon spectra.