Two Indium Sulfate Tellurites: Centrosymmetric In₂(SO₄)(TeO₃)(OH)₂(H₂O) and Non-centrosymmetric In₃(SO₄)(TeO₃)₂F₃(H₂O)

Abstract

Two new indium sulfate tellurites, namely, In₂(SO₄)(TeO₃)(OH)₂(H₂O) and In₃(SO₄)(TeO₃)₂F₃(H₂O), were synthesized by hydrothermal method in a one-pot reaction. Their pure phase yields have been successfully optimized to 76% and 21%, respectively. In₂(SO₄)(TeO₃)(OH)₂(H₂O) crystallized in centrosymmetric (CS) space group P2₁/n, while In₃(SO₄)(TeO₃)₂F₃(H₂O) formed a non-centrosymmetric (NCS) and chiral space group P2₁2₁2₁. The CS compound features a 2D layered structure composed of 2D indium oxide layers decorated by sulfate tetrahedra and tellurite groups. The NCS compound displays a 3D network consisting of indium tellurite layers bridged by sulfate tetrahedra. Powder second harmonic generation measurements disclosed that In₃(SO₄)(TeO₃)₂F₃(H₂O) exhibits a weak frequency-doubling efficiency about 11% of the commercial KDP. Its powder laser damage threshold quantity was estimated to be 79.6 MW/cm², which is about 36 times that of AGS. The two samples present wide optical band gaps of 4.86 and 4.10 eV, respectively, which were determined by Te, In, and O atoms based on density functional theory calculations.