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

The new antimony oxyhalide Sb3O4Cl has been synthesized hydrothermally. Its crystal structure has been determined using a twinned specimen. Sb3O4Cl crystallizes monoclinic in P2/C, a = 9.6531(8) Angstrom, b = 5.3059(3) Angstrom, c = 5.5981(4) Angstrom and beta = 94.745(10)degrees. Sb3O4Cl consists of infinite Sb3O4. 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 xi kl.