Materials Data on HgI by Materials Project
HgI crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Hg1+ is bonded to one Hg1+ and five equivalent I1- atoms to form a mixture of distorted edge and corner-sharing HgHgI5 octahedra. The corner-sharing octahedral tilt angles are 15°. The Hg–Hg bond length is 2.67 Å. There are one shorter (2.77 Å) and four longer (3.70 Å) Hg–I bond lengths. I1- is bonded in a 1-coordinate geometry to five equivalent Hg1+ atoms.