The crystal structure of paramelaconite, Cu₁₂²⁺Cu₄⁺O₁₄

Use of silane agents and poly(propylene‐g‐maleic anhydride) copolymer as adhesion promoters in glass fiber/polypropylene composites

“…To date, it has only been synthesized as thin films, never as a bulk material. The crystallographic data 80–83 are collected in Table 4.…”

Structural and electronic properties of Cu4O3 (paramelaconite): the role of native impurities

“…Paramelaconite (Cu 4 O 3 ) is the least explored oxide of copper. First reports on the structure of Cu 4 O 3 date back to the works of Clifford Frondel [1] and Datta et al [2], who defined paramelaconite as an oxygen-deficient tetragonal copper oxide, where the omission of oxygen atoms is compensated by the appearance of cuprous ions in place of cupric ones. However, both proposed structures had a unit cell content of Cu 16 O 14 , which was later attributed to the presence of admixed CuO in the sample.…”

“…A refined structure with the unit cell content of Cu 16 O 12 (i.e., Cu 4 O 3 ) was identified by O'Keeffe and Bovin [3]. The correct chemical formula of paramelaconite is Cu 1+ 2 Cu 2+ 2 O 3 , with two distinct copper atoms, Cu (1) and Cu (2). The first one, Cu (1), is cuprous copper and has two nearest neighbour oxygen atoms, O(1), forming collinear bonds of length 1.87 Å as found in Cu 2 O.…”

A Convenient Surfactant‐Mediated Hydrothermal Approach to Control Supported Copper Oxide Species for Catalytic Upgrading of Glucose to Lactic Acid

“…Three kinds of copper oxides are known to exist naturally: tenorite (CuO), cuprite (Cu 2 O), and paramelaconite (Cu 4 O 3 ) with monoclinic, cubic, and tetragonal crystal structures, respectively . Cu 4 O 3 is an intermediate oxide of copper between Cu 2 O and CuO, and is commonly written as Cu + 2 Cu 2+ 2 O 3 . According to the thermodynamics, the oxidation states of copper are known to vary as a function of temperature and oxygen partial pressure …”

“…[14] Three kinds of copper oxidesa re known to exist naturally:t enorite (CuO), cuprite( Cu 2 O), and paramelaconite (Cu 4 O 3 )w ith monoclinic, cubic, and tetragonal crystal structures, respectively. [15][16][17][18] [18][19][20] According to the thermodynamics, the oxidation states of coppera re known to vary as af unction of temperature and oxygen partial pressure. [21,22] It has been suggested that catalysis over copper oxides is significantly influenced by the surface states and defects.…”