Synthesis, Crystal Structures, and Thermal Analyses of Two New Antimony Tellurite Sulfates: [Sb₂(TeO₄)](SO₄) and [Sb₂(TeO₃)₂](SO₄)

Abstract

Two new antimony (III) tellurite sulfates [Sb 2 (TeO 4 )](SO 4 ) ( 1) and [Sb 2 (TeO 3 ) 2 ](SO 4 ) (2) were successfully synthesized through a conventional hydrothermal method and their crystal structures were determined by X-ray single crystal analysis.[Sb 2 (TeO 4 )](SO 4 ) crystallizes in the triclinic space group Pī (No. 2) with lattice parameters a = 5.572(2), b = 7.247(2), c = 9.540(3) Å, V = 358.5( 2) Å 3 , and Z = 2, while [Sb 2 (TeO 3 ) 2 ](SO 4 ) crystallizes in the orthorhombic space group Pbca (No. 61) with lattice parameters a = 7.368(2), b = 14.571(3), c = 16.521(3) Å, V = 1773.7(6) Å 3 , and Z = 8. The structure of [Sb 2 (TeO 4 )](SO 4 ) features a three-dimensional framework, composed of [SbO 4 ] trigonal bipyramids and [TeO 4 ] polyhedra to form a cationic 2 1[Sb 2 (TeO 4 )] 2 + corrugated cationic layers along [100], linked by SO 4 2À anions. [Sb 2 (TeO 3 ) 2 ](SO 4 ) forms a three-dimensional framework consisting of two dimensional wrinkled layers of 2 1[Sb 2 (TeO 3 ) 2 ] 2 + that are linked by SO 4 2À anions. The band gaps of 4.16 eV and 3.72 eV for [Sb 2 (TeO 4 )](SO 4 ) and [Sb 2 (TeO 3 ) 2 ](SO 4 ) respectively are estimated from the solid state UV-vis-NIR diffuse reflectance spectra. Thermal analysis indicated that both compounds are thermally stable up to about 500°C. The electrochemical specific capacity of [Sb 2 (TeO 4 )](SO 4 ) was determined to 245 mA h g À 1 on the first cycle in a Li-ion half-cell, the capacity remains at about 106 mA h g À 1 after 500 cycles.

Sb4O3(TeO3)2(HSO4)(OH): An Antimony Tellurite Sulfate Exhibiting Large Optical Anisotropy Activated by Lone Pair Stereoactivity

“…The absorption peaks at about 682, 600, and 457 cm –1 are ascribed to the bending vibrations of S–O bonds and the stretching vibrations of Te–O and Sb–O bonds. These assignments are consistent with the structural analysis. − …”