Results for “Cu(BrO4)2” | Engineering Papers

DOE OSTI2020

Materials Data on Cu(BrO4)2 by Materials Project

Cu(O4Br)2 crystallizes in the orthorhombic Pbca space group. The structure is two-dimensional and consists of two Cu(O4Br)2 sheets oriented in the (0, 0, 1) direction. Cu is bonded in a distorted octahedral geometry to six O atoms. There are a spread of Cu–O bond distances ranging from 1.75–2.41 Å. There are four inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Br atom. The O–Br bond length is 1.64 Å. In the second O site, O is bonded in a single-bond geometry to one Cu atom. In the third O site, O is bonded in a bent 120 degrees geometry to one Cu and one Br atom. The O–Br bond length is 1.66 Å. In the fourth O site, O is bonded in a bent 120 degrees geometry to one Cu and one Br atom. The O–Br bond length is 1.83 Å. Br is bonded in a trigonal non-coplanar geometry to three O atoms.

36 MATERIALS SCIENCE↗

NASA NTRS1991

Ternary and quaternary oxides of Bi, Sr and Cu

Before the discovery of superconductivity in an oxide of Bi, Sr, and Cu, the system Bi-Sr-Cu-O had not been studied, although several solid phases had been identified in the two-component regions of the ternary system Bi2O3-Si-O-CuO. The oxides Sr2CuO3, SrCu2O2, SrCuO2, and Bi2CuO4 were then well known and characterized, and the phase diagram of the binary system Bi2O3-SrO had been established in the temperature range 620 to 1000 C. Besides nine solutions of compositions Bi(2-2x) Sr(x) O(3-2x) and different symmetries, this diagram includes three definite compounds of stoichiometries Bi(2)BrO4. Bi2Sr2O5, and Bi2Sr3O6 (x - 0.50, 0.67 and 0.75 respectively), only the second of which with known unit-cell of orthorhombic symmetry, dimensions (A) a = 14.293(2), b = 7.651(2), c = 6.172(1), and z = 4. The first superconducting oxide in the system Bi-Sr-Cu-O was initially formulated as Bi2Sr2Cu2O(7+x), with an orthorhombic unit-cell of parameters (A) a = 5.32, b = 26.6, c = 48.8. In a preliminary study the same oxide was formulated with half the copper content, Bi(2)Sr(2)CuO(6+x), and index its reflections assuming an orthorhombic unit-cell of dimensions (A) a = 5.390(2), b = 26.973(8), c = 24.69(4). Subsequent studies by diffraction techniques have confirmed the composition 2:2:1. A new family of oxygen-deficient perovskites, was characterized, after identifying by x ray diffraction the phases present in the products of thermal treatments of about 150 mixtures of analytical grade Bi2O3, Sr(OH)2-8H2O and CuO at different molar ratios. X ray diffraction data are presented for some other oxides of Bi and Sr, as well as for various quaternary oxides, among them an oxide of Bi, Sr, and Cu.

Casais, M. T.↗