The crystal structure of sodium tetrasulphide, Na₂S₄

Abstract

Sodium tetrasulphide, Na2S4, is tetragonal and crystallizes in space group I742d with cell dimensions a = 9.5965(3) and c = 11.7885(5) A, and with Z= 8. Three-dimensional intensity data were collected with a linear diffractometer (PAILRED) using Mo Ira radiation. Positional and anisotropic temperaturefactor parameters for all atoms were refined by a full-matrix least-squares method to R (F)= 0.030 based on 1749 independent reflexions with lo>A1. The crystal structure is built up of unbranched $42-ions surrounded by Na + ions. The distance between different S]-ions is about 3.60 A. The $24 -ions lie on a twofold axis and the sulphur-sulphur bond distances are 2.074(1) A (end) and 2.061(1) A (middle). The sulphur-sulphur bond angle is 109.76(2) ~ and the dihedral angle is 97.81 °. The sodium-sulphur coordination polyhedra consists of two types: a distorted tetrahedron with two pairs of distances of 2.826(I) and 2-842(1) ~ and a distorted octahedron with three pairs of distances of 2.887(1), 3.043(1) and 3"081(1) A.

Stable Crystalline Forms of Na Polysulfides: Experiment versus Ab Initio Computational Prediction

“…Examination of powder XRD patterns of Na polysulfide samples prepared in our laboratory (Figure S1 in the Supporting Information) shows that the crystal structures of the Na 2 S, Na 2 S 2 , and Na 2 S 4 samples are indeed those described in the literature and that the material with a stoichiometry of 2 Na:3 S rather crystallizes as a mixture of Na 2 S 2 and Na 2 S 4 than as a congruous Na 2 S 3 . The recorded XRD pattern of one Na 2 S 5 sample does not agree with the diffraction pattern of any of the forms experimentally detected so far.…”

Some structures containing stellae quadrangulae

“…A similar framework of SQ's, although more collapsed, is found in the structure of Na2S 4 (Tegman, 1973), Fig. 10.…”

First-Principles Study on Structural and Electronic Properties of α-S and Na–S Crystals

“…Experimental lattice parameters and atomic positions have been reported for the Na-S crystals. [40][41][42][43][44][45] Table II shows lattice constants and Wycoff atomic positions fully-optimized by PBE calculations and experimental values for orthorhombic Na 2 S 5 (space group Pnma), tetragonal Na 2 S 4 (I " 42d), hexagonal ¡-Na 2 S 2 (P " 62m), hexagonal ¢-Na 2 S 2 (P6 3 =mmc), and cubic Na 2 S (Fm " 3m), respectively. All the lattice constants calculated by PBE agree well with the experiments, overestimating within the range from +0.2 to +1.9%.…”