  MnTiO3 has been studied for many decades, but it was only in the last few
years that its strong magnetoelectric behavior had been observed. Here, we use
neutron scattering on two separately grown single crystals and two powder
samples to show the presence of a supercell that breaks R-3 symmetry. We also
present the temperature and field dependence of the dielectric constant and
pyroelectric current, and show evidence of non-zero off-diagonal
magnetoelectric tensor elements (forbidden by R-3 symmetry) followed by a
polarization flop accompanying the spin flop transition at {\mu}0HSF = 6.5 T.
M\"ossbauer spectroscopy on MnTiO3 gently doped with 57Fe was used to help shed
light on the impact of the supercell on the observed behavior. Although the
full supercell structure could not be solved at this time due to a lack of
visible reflections, the full-scope of the results presented here suggest that
the role of local spin-lattice coupling in the magnetoelectric properties of
MnTiO3 is likely more important than previously thought.
