Copper(I) selenide is an
inorganic
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''.
Inor ...
binary compound between
copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
and
selenium
Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...
, with the chemical formula Cu
2Se.
Properties
Stoichiometric
Stoichiometry () is the relationships between the masses of reactants and products before, during, and following chemical reactions.
Stoichiometry is based on the law of conservation of mass; the total mass of reactants must equal the total m ...
copper selenide is a zero-
bandgap
In solid-state physics and solid-state chemistry, a band gap, also called a bandgap or energy gap, is an energy range in a solid where no electronic states exist. In graphs of the electronic band structure of solids, the band gap refers to the ...
material with metal-like behavior. Copper-deficient Cu
2−''x''Se (
non-stoichiometric
Non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having chemical element, elemental composition whose proportions cannot be represented by a ratio of small natural numbers (i.e. an empirical formula); ...
) is an intrinsic
p-type semiconductor with direct and indirect bandgap energies in the range of 2.1–2.3 eV and 1.2–1.4 eV respectively. It is frequently grown as
nanoparticle
A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At ...
s or other
nanostructures.
Uses
Copper(I) selenide is produced
in situ
is a Latin phrase meaning 'in place' or 'on site', derived from ' ('in') and ' ( ablative of ''situs'', ). The term typically refers to the examination or occurrence of a process within its original context, without relocation. The term is use ...
to form a protective black coating on iron or steel parts in some
cold-bluing processes. Bluing solutions that operate in this manner will typically be labeled as containing
selenous acid or
selenium dioxide. It has also been investigated for use in the treatment of colon cancer.
Natural occurrences
Copper selenides are the most common selenium minerals. Cu
2Se occurs as two polymorphs:
berzelianite (isometric, more common) and bellidoite (tetragonal). There are more natural Cu selenides to date, including
umangite, Cu
3Se
2 and
athabascaite, Cu
5Se
4.
See also
*
Copper(II) selenide
*
Gallium(II) selenide
*
Indium(III) selenide
*
Copper indium gallium selenide
*
Copper(II) sulfate
*
Selenium dioxide
*
Selenous acid
References
{{Selenides
Copper(I) compounds
Selenides