Fe₈Li₂O₁₆Sn₂

Architectural potential

An iron-oxide structural ceramic in the load-bearing brick register, carrying a real-colour solar-absorber overlay that turns the wall itself into a thermal collector. At 100 MPa it sits below the flagship structural ceramics but well within the compressive band of a good fired brick, so block-work, extruded post and compressive-vault experiments are within reach. The visible-absorber chemistry is the architectural opening: the amber-brown face takes visible light into itself rather than reflecting it, warming the mass by several degrees above an insulated wall of the same envelope. Natural placements are south-facing thermal-mass walls in passive-solar houses where the absorber-plus-storage logic is built into the single element, rammed-earth-adjacent pavilion walls where the iron colour reads as geological, hypocaust-style floor slabs in gallery and chapel interiors, and trombe-wall infills where the warm tone is part of the visible surface rather than hidden behind a glazed cavity. Compression is enough for two- or three-storey masonry; beyond that, a reinforced frame takes over. The caveat is CO₂: 258 per cent above clay brick, which forbids bulk use and pushes specification to signature thermal-wall work rather than to repeated brick runs. Supply-chain score is zero on the tin-oxide content, which also limits scale; the material belongs in prototype passive-solar work.

Material character

The body reads a saturated amber-brown pulled from the iron-oxide matrix, warmer and more umber than a standard clay brick and darker along the solar-absorbing face — a deliberate heat-capturing tone, closer in register to a weathered cor-ten panel than to a standard fired brick. At 5.03 g/cm³ and 70×70×41 mm the slab handles with real structural-brick heft, a firm two-hand lift that reads closer to a dense terracotta than to ordinary fired clay. Surface finishes vitrified-matte from the 1100 °C fire, the iron-oxide skin slightly darker than the body underneath; edges cold-cut, kerf-whitened. The colour runs uniformly through the slab so cut edges read the same amber-brown as the face, useful for exposed-arris detailing.