Molecular formula: CeO₂

Cerium(IV) oxide, ceric oxide, ceria, or sometimes simply cerium oxide or cerium dioxide, is a pale yellow-white powder, CeO_2. It is used in ceramics, to polish glass, and to sensitize photosensitive glass. It is also used in lapidary as "jeweller's rouge"; it is also known as "optician's rouge". Ceria is used in the walls of self-cleaning ovens as a hydrocarbon catalyst during the high-temperature cleaning process.

It is slightly hygroscopic and will also absorb a small amount of carbon dioxide from the atmosphere.

Molecular formula: Ce_0.8Gd_0.2O_2-x

Substituting a fraction of the Cerium Oxide ceria with gadolinium will introduce oxygen vacancies in the crystal without adding electronic charge carriers. This increases the ionic conductivity and results in a better electrolyte.

Molecular formula: Ce_0.8Sm_0.2O_2-x

Substituting a fraction of the Cerium Oxide ceria with samarium will introduce oxygen vacancies in the crystal without adding electronic charge carriers. This increases the ionic conductivity and results in a better electrolyte.

Molecular formula: Fe₂O₃

Iron(III) oxide or ferric oxide (Fe₂O₃): known in its natural state as rouge or hematite (also haematite), but also purified for use as a coating in magnetic audio and computer media, where it is known as ferric oxide. In a dry or alkaline environment it can cause passivation and inhibits rust. It is also a component of rust.

Molecular formula: Fe₃O₄

Iron(II,III) oxide or ferrous ferric oxide (Fe₃O4): better known as the black-coloured mineral magnetite or lodestone also seen on Mars. Also a main source of iron, magnetite is an iron ore. This form of iron oxide tends to occur when iron corrodes underwater, and so is often found inside tanks or below the waterline of ships.

Molecular formula: 3YSZ

A common electrolyte material

Molecular formula: 8YSZ

A common electrolyte material

Molecular formula: TiO₂

Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO₂. When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891.

Molecular formula: SnO₂

Tin dioxide, SnO₂, also stannic oxide, is an oxide of tin, with tin in oxidation state +4. The naturally occurring mineral is called cassiterite. When hydrated, it may be called stannic acid.

Molecular formula: BaTiO₃

Barium titanateis an oxide of barium and titanium with the chemical formula BaTiO₃. It is a ferroelectric ceramic material, with a photorefractive effect and piezoelectric properties. It has four phases as a solid, listing from high temperature to low temperature: cubic, tetragonal, orthorhombic, and rhombohedral crystal structure. All of the structures exhibit the ferroelectric effect except cubic.