The crystal structure of antimony telluroiodide, SbTel

Abstract

The crystal structure of SbTel has been determined with 538 independent reflections using three-dimensional intensities measured on a computer-controlled Philips PW 1100 single-crystal diffractometer. The cell constants, obtained by least-squares calculation from direct 9-value measurements on the diffractometer, are: α = 13.7008 (10), b = 4.2418(3), c = 9.2005(8) Â, β = 128.631(4) °,Z = 4; space group C2/m. The positional and thermal parameters with anisotropic temperature factors, were refined by full-matrix, least-squares calculations to a final R = 0.031.Each Sb atom is seven-coordinated by three Te atoms at distances 2.831 to 2.961 Â and four I atoms at distances 3.230 to 3.827 Â. The four I atoms form a parallelogram with two opposite sides parallel to b, while the three Te atoms form an isosceles triangle perpendicular to (010), with its base parallel to b. The four I atoms and two of the Te atoms are at the vertices of a triangular prism parallel to b and of height equal to b. The third Te atom is at the apex of a pyramid whose base is one of the Te 2

Optical, electronic, and elastic properties of some A5B6C7ferroelectrics (A=Sb, Bi; B=S, Se; C=I, Br, Cl): First principle calculation

“…The obtained band gap value for BiTeI compound is too high for the experimental and theoretical values [6,[29][30][31], but this value is a little higher than the theoretical value [33]. The values of BiTeBr, BiTeCl, and BiSI compounds are in agreement with the experimental and theoretical values [33,36,[38][39][40]. Unfortunately, there are no theoretical and experimental results for comparing with the band gap value of SbTeI compound.…”

“…Therefore, the geometric optimization process is performed to detect that the structure is the correct structure. The lattice parameters obtained as a result of optimization are given in Table 1 [29,30,[33][34][35][36][37][38].…”

“…Such a low value is a good indicator for an adequate convergence of the calculations. [30][31][32][33][34][35][36][37][38][39]. The atomic positions belonging to these compounds are given in Table 1.…”

The crystal structure of arsenic telluroiodide, As5Te7I

“…Between the bands a tunnel of three octahedra width is formed. This description of the structure with the help of the composite polyhedron, the existence of which has been ascertained in the crystal structures of antimony and bismuth chalcohalogenides (Voutsas and Rentzeperis, 1980, 1934Papazoglou and Rentzeperis, 1983) permits a satisfactory explanation of the connection between the bands and also of Brought to you by | New York University Bobst Library Technical Service Authenticated Download Date | 6/17/15 1:12 AM the needle-like growth of the crystals along the b axis and their brittleness. It should be noted, however, that the structures of the latter are different from those of As 2 Te 3 (Stergiou and Rentzeperis, 1985) and the present structure of As 5 Te 7 I, since they are composed only of composite polyhedra.…”

Crystal structure of bismuth selenochloride, BiSeCl

“…In the structures of BiSCl, BiSBr, SbSel (Voutsas and Rentzeperis, 1980;1984) and SbTel (Papazoglou and Rentzeperis, 1983) the Sb and Bi atoms are seven-coordinated, with the coordinating atoms forming a composite polyhedron. In the structures of Sb 2 Se 2 (Voutsas, Papazoglou, Rentzeperis and Siapkas, 1985), As 2 Te 3 , As 5 Te 7 I Brought to you by | New York University Bobst Library Technical Service Authenticated Download Date | 6/11/15 10:51 PM (Stergiou and Rentzeperis,198S) on the other hand, the coordination polyhedra are both octahedra and composite polyhedra, similar to the previous one.…”