Structure of triantimony tetraoxide chloride, Sb3O4Cl : twinning and one-dimensional disorder

The new antimony oxyhalide Sb 3 O 4 Cl has been synthesized hydrothermally. Its crystal structure has been determined using a twinned specimen. Sb 3 O 4 Cl crystallizes monoclinic in P2/c, a = 9.6531(8) A, b = 5.3059(3) A, c = 5.5981(4) A and β = 94.745(10)°. Sb 3 O 4 Cl consists of infinite Sb 3 O 4 layers parallel to (100) and interlayer Cl atoms. Twinning occurs if (100) mirror planes are inserted instead of the twofold rotation axes at the Cl positions. One-dimensional disorder including orthorhombic Pmca micro-domains gives rise to the weak diffuse reflections along ξkl.