Synthesis and characterization of orthorhombic TlSr<SUB>2</SUB>CuO<SUB>5</SUB>

TlSr<SUB>2</SUB>CuO<SUB>5</SUB> has been synthesized in polycrystalline form. Powder X-ray diffraction studies indicate an orthorhombic structure; space group Pmmm; a = 3.661(2), b = 3.793(1), c = 8.99(3)Å. The presence of short Cu-O bonds indicates the high formal valence for Cu. TlSr<SUB>2</SUB>CuO<SUB>5</SUB> is found to be metallic and no superconductivity could be observed down to 4.2 K