Potassium niobate (KNbO
3) is an
inorganic compound
An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bondsthat is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''.
Inorgan ...
with the formula KNbO
3. A colorless solid, it is classified as a
perovskite
Perovskite (pronunciation: ) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula ). Its name is also applied to the class of compounds which have the same type of crystal structure as , known as the perovskite (stru ...
ferroelectric
In physics and materials science, ferroelectricity is a characteristic of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. All ferroelectrics are also piezoel ...
material.
It exhibits nonlinear optical properties, and is a component of some lasers.
Nanowires of potassium niobate have been used to produce tunable coherent light.
Structure
On cooling from high temperature, KNbO
3 undergoes a series of structural
phase transition
In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic Sta ...
s. At 435 °C, the crystal symmetry changes from cubic centrosymmetric (Pmm) to
tetragonal
In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the Cube (geometry), cube becomes a rectangular Pri ...
non-centrosymmetric (P4mm). On further cooling, at 225 °C the crystal symmetry changes from tetragonal (P4mm) to
orthorhombic
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic Lattice (group), lattices result from stretching a cubic crystal system, cubic lattice along two of its orthogonal pairs by two different factors, res ...
(Amm2) and at −50 °C from
orthorhombic
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic Lattice (group), lattices result from stretching a cubic crystal system, cubic lattice along two of its orthogonal pairs by two different factors, res ...
(Amm2) to
rhombohedral
In geometry, a rhombohedron (also called a rhombic hexahedron or, inaccurately, a rhomboid) is a special case of a parallelepiped in which all six faces are congruent rhombus, rhombi. It can be used to define the rhombohedral lattice system, a Ho ...
(R3m).
Applications and research
In addition to research in electronic memory storage,
potassium niobate is used in
resonant doubling.
This technique allows small infrared lasers to convert output into blue light, a critical technology for the production of blue lasers and technology dependent upon them.
Potassium niobate has been found useful in many different areas of
materials science
Materials science is an interdisciplinary field of researching and discovering materials. Materials engineering is an engineering field of finding uses for materials in other fields and industries.
The intellectual origins of materials sci ...
,
including properties of
lasers
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radi ...
,
quantum teleportation
Quantum teleportation is a technique for transferring quantum information from a sender at one location to a receiver some distance away. While teleportation is commonly portrayed in science fiction as a means to transfer physical objects from on ...
,
and it has been used to study the optical properties of particulate
composite materials
A composite or composite material (also composition material) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a ...
.
Safety
The for potassium niobate is 3000 mg/kg (oral, rat).
References
{{Niobium compounds
Potassium compounds
Niobates
Nonlinear optical materials
Ferroelectric materials
Perovskites
Piezoelectric materials