Two different polymorphs of the new selenosilicate NaSiSe were synthesized by solid-state reactions. The high-temperature polymorph NaSiSe-24 crystallizes in the tetragonal space group 4/ (No. 132) with lattice parameters = 7.2793(2) Å, = 12.4960(4) Å, and = 662.14(3) Å. The main structural motifs are isolated SiSe units of two edge-sharing SiSe tetrahedra. The high-pressure/low-temperature polymorph NaSiSe-48 crystallizes in the orthorhombic space group (No. 61) with lattice parameters = 12.9276(1) Å, = 15.9324(1) Å, = 6.0349(1) Å, and = 1243.00(2) Å showing single chains [SiSe]. The lattice parameters of NaSiSe-24 were determined by single-crystal X-ray diffraction, whereas those of NaSiSe-48 were investigated by powder X-ray diffraction. Both modifications crystallize in new structure types. An energetic comparison of the two polymorphs and further hypothetical structure types was carried out by density functional theory modeling. Calculations reveal that the polymorphs are very close in energy (Δ = 3.4 kJ mol). Impedance spectroscopic measurements show ionic conductivity (σ = 1.4 × 10 S cm at 50 °C and 6.8 × 10 S cm at 200 °C) with an activation energy of = 0.54(2) eV for NaSiSe-48.

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.inorgchem.3c01111DOI Listing

Publication Analysis

Top Keywords

lattice parameters
12
space group
8
x-ray diffraction
8
structure types
8
synthesis characterization
4
characterization nasise-24
4
nasise-24 and nasise-48 two
4
polymorphs
4
and nasise-48 two polymorphs
4
polymorphs anionic
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!