DOE OSTI2020
Na3OI crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are six inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a linear geometry to two O2- and four I1- atoms. There are one shorter (2.29 Å) and one longer (2.35 Å) Na–O bond lengths. There are a spread of Na–I bond distances ranging from 3.41–3.56 Å. In the second Na1+ site, Na1+ is bonded in a linear geometry to two O2- and four I1- atoms. There are one shorter (2.29 Å) and one longer (2.35 Å) Na–O bond lengths. There are a spread of Na–I bond distances ranging from 3.41–3.56 Å. In the third Na1+ site, Na1+ is bonded in a distorted L-shaped geometry to two O2- and four I1- atoms. Both Na–O bond lengths are 2.33 Å. There are a spread of Na–I bond distances ranging from 3.39–3.42 Å. In the fourth Na1+ site, Na1+ is bonded in a linear geometry to two O2- and four I1- atoms. There are one shorter (2.29 Å) and one longer (2.35 Å) Na–O bond lengths. There are a spread of Na–I bond distances ranging from 3.42–3.55 Å. In the fifth Na1+ site, Na1+ is bonded in a linear geometry to two O2- and four I1- atoms. There are one shorter (2.29 Å) and one longer (2.35 Å) Na–O bond lengths. There are a spread of Na–I bond distances ranging from 3.42–3.56 Å. In the sixth Na1+ site, Na1+ is bonded in a distorted L-shaped geometry to two O2- and four I1- atoms. Both Na–O bond lengths are 2.33 Å. There are a spread of Na–I bond distances ranging from 3.39–3.42 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to six Na1+ atoms to form ONa6 octahedra that share corners with three equivalent INa12 cuboctahedra, corners with three equivalent ONa6 octahedra, faces with seven INa12 cuboctahedra, and a faceface with one ONa6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the second O2- site, O2- is bonded to six Na1+ atoms to form ONa6 octahedra that share corners with six equivalent ONa6 octahedra and faces with eight INa12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. In the third O2- site, O2- is bonded to six Na1+ atoms to form ONa6 octahedra that share corners with six equivalent ONa6 octahedra and faces with eight INa12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. In the fourth O2- site, O2- is bonded to six Na1+ atoms to form ONa6 octahedra that share corners with three equivalent INa12 cuboctahedra, corners with three equivalent ONa6 octahedra, faces with seven INa12 cuboctahedra, and a faceface with one ONa6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded to twelve Na1+ atoms to form INa12 cuboctahedra that share corners with nine INa12 cuboctahedra, corners with three equivalent ONa6 octahedra, faces with seven INa12 cuboctahedra, and faces with seven ONa6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second I1- site, I1- is bonded to twelve Na1+ atoms to form INa12 cuboctahedra that share corners with twelve INa12 cuboctahedra, faces with six INa12 cuboctahedra, and faces with eight ONa6 octahedra. In the third I1- site, I1- is bonded to twelve Na1+ atoms to form INa12 cuboctahedra that share corners with nine INa12 cuboctahedra, corners with three equivalent ONa6 octahedra, faces with seven INa12 cuboctahedra, and faces with seven ONa6 octahedra. The corner-sharing octahedral tilt angles are 2°.