Acta Crystallographica Section B

Structural Science

Volume 52, Part 3 (June 1996)

research papers

Acta Cryst. (1996). B52, 406-413 [ doi:10.1107/S0108768195016715 ]

A synchrotron X-ray study of the electron density in SmFeO₃

E. N. Maslen, V. A. Streltsov and N. Ishizawa

Abstract: Structure factors for small, hydrothermally grown samarium orthoferrite, SmFeO₃, were measured with focused [lambda] = 0.7 Å synchrotron radiation. Approximate high symmetry in the images indicates that cations deform the electron density far more strongly than the O atoms. The most obvious effect is on distribution of the Fe atoms. The influence of the nearest low-symmetry (C_s) O coordination on the electron density of the Sm cation is weak by comparison with that of the Sm-Fe interactions, as is illustrated by the high symmetry of the map near the Sm atom. The Sm-Fe interactions appear to affect the magnetic ordering and spin configuration of the Fe atoms. Space group Pnma, orthorhombic, M_r = 254.20, a = 5.6001 (3), b = 7.7060 (7), c = 5.3995 (6) Å, V = 233.01 (4) Å³, Z = 4, D_x = 7.246 Mg m^-3, _0.7 = 28.5 mm^-1, F(000) = 448, T = 293 K, R = 0.017, wR = 0.021, S = 3.83 (8) for 1329 unique reflections.