DOE OSTI2020
NaTl3O2Na3TlO2 crystallizes in the monoclinic Pm space group. The structure is two-dimensional and consists of one Na3TlO2 sheet oriented in the (0, 0, 1) direction and one NaTl3O2 sheet oriented in the (0, 0, 1) direction. In the Na3TlO2 sheet, there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are two shorter (2.26 Å) and one longer (2.29 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are two shorter (2.36 Å) and one longer (2.38 Å) Na–O bond lengths. In the third Na1+ site, Na1+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are one shorter (2.26 Å) and two longer (2.31 Å) Na–O bond lengths. Tl1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are one shorter (2.39 Å) and two longer (2.56 Å) Tl–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to five Na1+ and one Tl1+ atom to form edge-sharing ONa5Tl octahedra. In the second O2- site, O2- is bonded to four Na1+ and two equivalent Tl1+ atoms to form distorted edge-sharing ONa4Tl2 octahedra. In the NaTl3O2 sheet, Na1+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. All Na–O bond lengths are 2.28 Å. There are three inequivalent Tl1+ sites. In the first Tl1+ site, Tl1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are one shorter (2.59 Å) and two longer (2.65 Å) Tl–O bond lengths. In the second Tl1+ site, Tl1+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are two shorter (2.58 Å) and one longer (2.59 Å) Tl–O bond lengths. In the third Tl1+ site, Tl1+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are one shorter (2.42 Å) and two longer (2.55 Å) Tl–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to one Na1+ and five Tl1+ atoms to form edge-sharing ONaTl5 octahedra. In the second O2- site, O2- is bonded to two equivalent Na1+ and four Tl1+ atoms to form edge-sharing ONa2Tl4 octahedra.