![shrook ran shrook ran](https://img.itch.zone/aW1hZ2UvODI5NTMyLzQ2NTY4NzYucG5n/347x500/6%2Bu6u0.png)
![shrook ran shrook ran](https://i.pinimg.com/236x/15/44/9a/15449a1cfa7d34745846137b8b528ced--charlotte-le-bon.jpg)
Recent experimental reports could be explained by (i) a structural misassignment (ii) highly strained crystallites and (iii) high concentrations of lattice defects forming a superlattice structure. A spontaneous distortion from tetrahedral to trigonal-pyramidal arrangement is observed to occur. The predictions match the expectation from textbook inorganic chemistry that high-symmetry coordination environments are adopted by the Sn(IV) ion, but the Sn(II) ion favors asymmetric environments of low coordination. Good agreement with experiment is obtained, with the exception of zincblende SnS, which is predicted to be thermodynamically and dynamically unstable. In conclusion, we have assessed the structural and thermodynamic properties of SnS, SnS 2, and Sn 2S 3 from first-principles calculations. for nanoparticulate and thin-film tin sulfides, respectively. (10) Both of these patterns correspond exactly with the peak positions of the XRD of ZB SnS reported by both Greyson et al. In previous work, the intensity ratios predicted for ZB SnS were not adhered to in ascribing the ZB structure from the diffraction pattern, and this could be important in distinguishing between the two phases. We cannot account for the preferential orientation of crystals due to the dependence of the growth process on nucleation, (56) but a powder diffraction of each would show that ZB SnS exhibits a stronger (111) reflection at 2θ = 26.8°, whereas rocksalt SnS would have a stronger (002) reflection at 2θ = 31.0.
![shrook ran shrook ran](https://i.pinimg.com/originals/65/d8/f3/65d8f369055fae377592301fa5792b2e.jpg)
One can see that the peak positions and the reflections associated with each are equivalent, due to the common fcc crystal structure, and it would be possible to confuse the two. The predicted X-ray diffraction patterns for rocksalt and zincblende SnS, at the same lattice spacing, are shown in Figure 4. We conclude that the known rocksalt phase of SnS has been mis-assigned as zincblende in the recent literature. Ab initio molecular dynamics simulations reveal spontaneous degradation to an amorphous phase much lower in energy, as Sn(II) is inherently unstable in a regular tetrahedral environment. While theoretical X-ray diffraction patterns do agree with the assignment of the zincblende phase demonstrated in the literature, the structure is not stable close to the lattice parameters observed experimentally, exhibiting an unfeasibly large pressure and a formation enthalpy much higher than any other phase. We report the enthalpies of formation for the known phases of SnS, SnS 2, and Sn 2S 3, with good agreement between theory and experiment for the ground-state structures of each. Herein, first-principles calculations are employed to better understand this novel geometry and its place within the tin sulfide multiphasic system. Of particular note is the recent isolation of zincblende SnS in particles and thin-films. The various phases of tin sulfide have been studied as semiconductors since the 1960s and are now being investigated as potential earth-abundant photovoltaic and photocatalytic materials.