Bismuth silicon oxide

It occurs naturally as the mineral sillénite and can be produced synthetically, by heating a mixture of bismuth and silicon oxides.

Centimeter-sized single crystals of Bi12SiO20 can be grown by the Czochralski process from the molten phase.

They exhibit piezoelectric, electro-optic, elasto-optic, photorefractive[4] and photoconductive properties, and therefore have potential applications in spatial light modulators, acoustic delay lines and hologram recording equipment.

[1] Bi12SiO20 can be obtained as a whitish powder with band gap of approximately 3.2 eV starting from bismuth subcarbonate and silica in presence of ethyleneglycol.

Unlike the bismuth oxide, the presence of the acidic Si(IV) cations avoid the reactivity with CO2.