Crystal structure and properties of indium telluride [Ga(en) ₃]In ₃Te ₇

[Ga(en) ₃]In ₃Te ₇(I) has been synthesized by solvothermal technique using Rb ₂Te, GaCl ₃, InCl ₃ and Te as starting materials and ethylenediamine as solvent at 180°C for 7 days. The structure consists of a Zintl anion, _∞ ²[In ₃Te ₇] ^3- and a complex cation, [Ga(en) ₃] ³⁺. I belongs to the monoclinic, space group P2 ₁/c, (no.14), with unit cell dimensions: a = 1.0460(2)nm, b = 1.6981(3)nm, c = 1.4994(6)nm, β = 95.46(2)°, V = 2.651(1)nm ³, Z = 4. Optical studies were performed on the powder samples, which suggested that I is a semiconductor with a band gap of 1.65eV. The result of TGA thermal analysis on I indicated that the weight loss of enthylendiamine proceeded in three steps. The decomposition of I produced Ga ₂Te ₃, In ₂Te ₃, Te and ethylenediamine as the final residues.