Crystal structure of BaMg2Si2O7 and Eu2+ luminescence

Crystal structure of BaMg2Si2O7 was determined and refined by a combined powder X-ray and neutron Rietveld method (monoclinic, C2/c, no. 15, Z=8, a=7.24553(8) Å, b=12.71376(14) Å, c=13.74813(15) Å, β=90.2107(8)°, V=1266.44(2) Å3; Rp/Rwp=3.38%/4.77%). The structure contains a single crystallographic type of Ba atom coordinated to eight O atoms with C1 (1) site symmetry. Under 325-nm excitation Ba0.98Eu0.02Mg2Si2O7 exhibits an asymmetric emission band around 402 nm. The asymmetric shape of the emission band is likely associated with a small electron–phonon coupling in BaMg2Si2O7. The integrated intensity of the emission band was observed to remain constant over the temperature range 4.2–300 K.

Crystal structure of BaMg2Si2O7 projected onto the bc plane. The MgO4 distorted tetrahedra form one-dimensional chains along the unit cell c-axis in the structure.Figure optionsDownload as PowerPoint slide