A new mixed anionic compound Cd 2 TeO 3 Cl 2 with unprecedented [Cd 2 O 6 Cl 4 ] octahedral dimers has been synthesized, and millimeter-scale single crystals of Cd 2 TeO 3 Cl 2 have been grown by the vertical Bridgman method with CdCl 2 as the flux. Cd 2 TeO 3 Cl 2 crystallizes in the centrosymmetric P 1̄ (no. 2) space group, and shows a mixed cationic layer structure constituted by distorted [TeO 3 ] motifs, mixed anionic [Cd 2 O 6 Cl 4 ] chains, and [Cd 2 O 6 Cl 4 ] octahedral dimers. Experimental and theoretical results show that Cd 2 TeO 3 Cl 2 is a direct band gap compound with an experimental band gap of ∼4.25 eV. Meanwhile, the compound has good optical transmittance in the 3-5 μm atmospheric window. The results indicate that Cd 2 TeO 3 Cl 2 could be used as a promising mid-IR window material, and could enrich the chemical and structural diversity of oxides.
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