A new layered cuprate Ba36Ca2Cu32O86-x has been synthesized using high pressure technique. It crystallizes in an orthorhombic cell with a ≈ 5.7 Å, b ≈ 9.8 Å and c ≈ 45.50 Å, space group Immm (or Imm2). The high resolution electron microscopy study shows that this original structure consists of oxygen deficient 4H-hexagonal BaCuO2+x layers, interleaved with barium-calcium layers. The proposed structural model suggests for copper, a pyramidal coordination. This new phase is described as the n = 4 member of a new structural family [Ba8Cu8O20]n[Ba4Ca 2O4]. Different higher n members (n = 7, 10, 13) are observed as defects by HREM.
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