Antimony triselenide is the
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...
Sb2 Se3. The material exists as the
sulfosalt
Sulfosalt minerals are sulfide minerals with the general formula , where
*A represents a metal such as copper, lead, silver, iron, and rarely mercury, zinc, vanadium
*B usually represents semi-metal such as arsenic, antimony, bismuth, and rarely ...
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...
antimonselite (
IMA symbol
A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different conc ...
: Atm), which crystallizes in an orthorhombic
space group
In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it unchan ...
. In this compound, antimony has a formal
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
+3 and selenium −2. The bonding in this compound has covalent character as evidenced by the black color and
semiconducting
A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. ...
properties of this and related materials.
The low-frequency dielectric constant (ε
0) has been measured to be 133 along the ''c'' axis of the crystal at room temperature, which is unusually large. Its band gap is 1.18 eV at room temperature.
The compound may be formed by the reaction of
antimony
Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient time ...
with
selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
and has a melting point of 885 K.
Applications
Sb
2Se
3 is now being actively explored for application thin-film solar cells. A record light-to-electricity conversion efficiency of 9.2% has been reported.
References
Selenides
Antimony(III) compounds
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