Fe₅O₂₄P₆Sr₂W

Architectural potential

A strontium-iron-phosphate-tungstate heavy-oxide ceramic fired at 1250 °C, 100 MPa of compression, and a dual functional layer that does not exist elsewhere in this batch: electrochromic tint-switching on a DC signal plus a permanent magnetic response from the iron fraction. Natural placements are hardware-free mountable cladding tiles that hold to a steel substrate by magnetism alone — changeable signage panels in a transit hall, reconfigurable partition tiles in an open-plan workspace, modular trombe-wall patches that can be rearranged seasonally without drilling. The thermal-mass base role stays intact: these are absorbing, re-radiating tiles that shift colour register through the daily cycle while remaining demountable. Against clay brick the embodied CO₂ runs 326 per cent higher, so the specification is signature-element only, and the amber-brown body carries a visible-absorber cast that makes the thermal argument legible by eye. The caveat is supply: the supply-chain score sits at zero, the precursor list crosses four separate rare streams, and 200 g workshop batches at €21.29 keep production at the demonstration scale. A single reconfigurable wall is plausible; a whole façade is not, and any specification should commit explicitly to the demonstration register rather than drift toward bulk cladding.

Material character

An amber-brown body characteristic of iron-phosphate-tungstate chemistry — warmer than the pure-tungstate siblings, deeper than an ordinary strontium-iron tile. At 4.09 g/cm³ and 85×85×34 mm the slab sits firm two-handed, close in lift register to the purple-brown iron-oxide block from the same batch. Surface vitrified skin, satin-matte, with a faint iridescent cast where the tungstate phase sits near the outer surface. Edges cold-cut, kerf-powdered. A small steel offcut held to the face sticks on contact — the magnetic signature is immediately legible by hand rather than by instrument. Against a plain iron-phosphate ceramic the body runs warmer and the post-switched state tints a clear blue-grey.