Layered Oxychlorides [PbBiO₂]A_<i>n</i>+1B_<i>n</i>O_{3<i>n</i>–1}Cl₂ (A = Pb/Bi, B = Fe/Ti): Intergrowth of the Hematophanite and Sillen Phases

New layered structures corresponding to the general formula [PbBiO₂]­A_<i>n</i>+1B_<i>n</i>O_{3<i>n</i>–1}Cl₂ were prepared. Pb₅BiFe₃O₁₀Cl₂ (<i>n</i> = 3) and Pb₅Bi₂Fe₄O₁₃Cl₂ (<i>n</i> = 4) are built as a stacking of truncated A_<i>n</i>+1B_<i>n</i>O_{3<i>n</i>–1} perovskite blocks and α-PbO-type [A₂O₂]²⁺ (A = Pb, Bi) blocks combined with chlorine sheets. The alternation of these structural blocks can be represented as an intergrowth between the hematophanite and Sillen-type structural blocks. The crystal and magnetic structures of Pb₅BiFe₃O₁₀Cl₂ and Pb₅Bi₂Fe₄O₁₃Cl₂ were investigated in the temperature range of 1.5–700 K using X-ray and neutron powder diffraction, transmission electron microscopy and ⁵⁷Fe Mössbauer spectroscopy. Both compounds crystallize in the <i>I</i>4/<i>mmm</i> space group with the unit cell parameters <i>a</i> ≈ <i>a</i>_p ≈ 3.92 Å (a unit-cell parameter of the perovskite structure), <i>c</i> ≈ 43.0 Å for the <i>n</i> = 3 member and <i>c</i> ≈ 53.5 Å for the <i>n</i> = 4 member. Despite the large separation between the slabs containing the Fe³⁺ ions (nearly 14 Å), long-range antiferromagnetic order sets in below ∼600 K with the G-type arrangement of the Fe magnetic moments aligned along the <i>c</i>-axis. The possibility of mixing d⁰ and dⁿ cations at the B sublattice of these structures was also demonstrated by preparing the Ti-substituted <i>n</i> = 4 member Pb₆BiFe₃TiO₁₃Cl<sub>2