Synthesis, crystal structure and magnetic characterization of Na 2Cu 5(Si 2O 7) 2: An inorganic ferrimagnetic chain

Abstract

The hydrothermal synthesis, crystal structure and magnetic properties of the new copper silicate Na 2Cu 5(Si 2O 7) 2, are reported. The crystal structure was determined through synchrotron powder diffraction data. The unit cell was indexed to a triclinic cell, space group P-1 (n° 2) with unit cell parameters a=5.71075(2) Å, b=7.68266(3) Å, c=7.96742(3) Å, α=64.2972(2)°, β=88.4860(2)° and γ=70.5958(2)° with Z = 1 . A structural model was obtained through a combination of a direct-space Monte-Carlo approach and Rietveld refinement. The crystal structure contains parallel chains consisting of zig-zag copper dimers and trimers. All silicon atoms are present as part of a [Si 2O 7] 6− anion that connects the chains; therefore the compound belongs to the sorosilicate mineral family. The magnetic susceptibility was measured and shows a behavior typical of one-dimensional ferrimagnetism, in agreement with the observed structure.