Tin Oxide

Tin Dioxide, SnO₂ or Sn(iv) oxide, is a white metal oxide that is sometimes sourced from the mineral cassiterite. It has uses in the ceramics and glass industry as well as chemical applications as a reducing agent and precursor to other tin compounds and salts.

Ceramic
As a ceramic-glaze material, tin glazes can be comparable to zircon ones as both are used as opacifiers. However, where zircon oxide produces a harder glaze, reduces thermal expansion more, and is more affordable, you can use much smaller amounts of tin oxide to achieve the same opacifying effects and add interesting color variation to the glaze. That being said, tin oxide can be found in many ceramic and glass pigments and glazes, and is usually combined with other metal oxides to produce certain colors.

Plastic Flame Retardant & SS
The compound zinc stannates (ZS) are sometimes added in plastics as an antimony-free fire retardant and smoke suppressant. They tend to work better in plastics that require less plasticizer additive materials.

Additional Notes:
* Tin glazes do not usually opacify in a reduction firing.