Abstract High-resolution electron microscopy and diffraction studies of fully oxidized and reduced Pb–Nb–W–O oxides are presented. The phases observed were superstructures of tetragonal tungsten bronze (TTB), formed by ordering of pentagonal columns (PCs) and pentagonal tunnels (PTs). In fully oxidized preparations, the structure progressed from a quaternary Nb 8 W 9 O 47 analogue to the K 5 Nb 9 W 2 O 31 structure, with an orthorhombic ∼√2 a TTB ×√2 a TTB × c TTB TTB superstructure having two PCs per cell. Electron diffraction determined the true structure as a 2 a TTB ×2 a TTB ×2 c TTB supercell. With further lead incorporation, lead-filled PTs replaced PCs, forming a quaternary TTB analogue. Reduced quaternary phases were prepared by reacting lead with Nb 8 W 9 O 47 . The structure was initially maintained in the quaternary phase, but converted at high-temperature to the K 5 Nb 9 W 2 O 31 type. Excess lead caused the formation of lead-rich interfaces between domains. Reaction of lead with oxides in the ratio 4Nb 2 O 5 :9WO 3 formed quaternary phases possessing the Nb 8 W 9 O 47 structure, demonstrating the direct synthesis of mixed PT/PC quaternary “bronze” phases which retained the structure of the oxidized ternary parent.