Crystal Structure of Lu4Si2O7N2Analyzed by the Rietveld Method Using the Time-of-Flight Neutron Powder Diffraction Pattern

The crystal structure of a lutetium silicon oxynitride (Lu 4 Si 2 O 7 N 2 ) was analyzed by the Rietveld method using time‐of‐flight (TOF) neutron powder diffraction data. The compound crystallizes in a monoclinic cell, space group P 2 1 / c (No. 14‐1) with a = 7.4243(1), b = 10.2728(1), c = 10.6628(1) Å, and β= 109.773(1)° at 297 K. One nitrogen atom in Lu 4 Si 2 O 7 N 2 occupies the bridging site between the two Si atoms, and the other one is statistically situated at the terminal sites of Si 2 O 5 N 2 ditetrahedra. In the local structure, Si 2 O 5 N 2 ditetrahedra consist of SiO 3 N and SiO 2 N 2 tetrahedral units sharing the N atom. Lu atoms are in sixfold, sevenfold (×2) and eightfold coordinations of O/N atoms. X‐ray powder diffraction data were also analyzed with the model obtained by the neutron diffraction.