[Mn(en)3]CdSnTe4 and [Mn(en)3]Ag6Sn2Te8: New Intermetallic Tellurides Synthesized in Superheated Organic Medium

Two intermetallic tellurides, Mn(en) 3 ]CdSnTe 4 ( I ) and [Mn(en) 3 ]Ag 6 Sn 2 Te 8 ( II ), have been synthesized in superheated ethylenediamine solutions at 180 °C. Single-crystal X-ray diffraction analyses show that I crystallizes in triclinic crystal system, space group P 1 (No. 1) with lattice parameters a = 9.134(2) Å, b = 10.085(3) Å, c = 12.691(3) Å, α = 73.52(2)°, β = 86.05(2)°, γ = 76.43(2)°, V = 1089.7(5) Å 3, and Z = 2 and II belongs to trigonal (rhombohedral) crystal system, space group R 3̄ m (No. 166) with a = 8.9590(9) Å, c = 34.795(2) Å, V = 2418.6(4) Å 3, and Z = 3. Both compounds possess new structure types. The structure of I is composed of one-dimensional Zintl chains of alternating edge-sharing MTe 4 (M = Cd, Sn) tetrahedra and [Mn(en) 3 ] 2+ complex cations that are between the chains. The structure of II contains two-dimensional double layers of Ag 6 Sn 2 Te 8 2 - formed by connecting two single honeycomb-like layers through M−Te bonds (M = Ag, Sn). The double layers are separated by the [Mn(en) 3 ] 2+ templates. Optical diffuse reflectance measurements have been performed on the powder samples of I and II and have suggested that both compounds are semiconductors with band gaps of 1.75 and 0.77 eV, respectively.