Our aim is to study with high resolution neutron powder diffraction the two orthorhombic phases of Mn2TeO6 at RT, so as to understand the origin of the observed structural differences, which could originate in particular in different orderings between Mn and Te. In parallel, in situ neutron diffraction will be performed versus temperature in O2 flow, to study (i) a transition to a tetragonal phase around 350°C and (ii) the formation of new phases of different stoichiometry above 700°C. Low temperature neutron diffraction experiments will be carried out as well, in order to investigate the magnetic structures of the two orthorhombic phases, which show very different susceptibility characteristics.