Synthesis, crystal structure and magnetic characterization of Na2Cu5(Si2O7)2: An inorganic ferrimagnetic chain

The hydrothermal synthesis, crystal structure and magnetic properties of the new copper silicate Na2Cu5(Si2O7)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=1Z=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 [Si2O7]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.

A novel copper silicate was synthesized through hydrothermal methods. Its crystal structure was determined from powder diffraction data. It comprises zig-zag chains of copper dimers and trimers. Its magnetic behavior is characteristic of one dimensional ferrimagentism. A magnetic exchange sequence is proposed based on structural arguments.Figure optionsDownload as PowerPoint slide