Thallium(I) oxide is the
inorganic compound of
thallium
Thallium is a chemical element with the symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes an ...
and
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
with the formula Tl
2O in which thallium is in its +1
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 ...
. It is black and produces a
basic yellow solution of
thallium(I) hydroxide (TlOH) when dissolved in water. It is formed by heating solid TlOH or Tl
2CO
3 in the absence of air. Thallium oxide is used to make special high
refractive index
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.
The refractive index determines how much the path of light is bent, or ...
glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...
. Thallium oxide is a component of several
high temperature superconductor
High-temperature superconductors (abbreviated high-c or HTS) are defined as materials that behave as superconductors at temperatures above , the boiling point of liquid nitrogen. The adjective "high temperature" is only in respect to previ ...
s. Thallium(I) oxide reacts with
acids to make thallium(I) salts.
Tl
2O adopts the anti-
cadmium iodide
Cadmium iodide is the inorganic compound with the formula CdI2. It is a white hygroscopic solid. It also can be obtained as a mono- and tetrahydrate. It has few applications. It is notable for its crystal structure, which is typical for compoun ...
structure in the solid state.
[ In this way, the Tl(I) centers are pyramidal and the oxide centers are ]octahedral
In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet a ...
.
Thallium(I) oxide, like all thallium compounds, is highly toxic.
Preparation
Thallium(I) oxide can be produced by decomposition of thallium(I) hydroxide at 100 °C or by heating thallium(III) oxide in the absence of air to 700 °C.
References
External links
U.S. Geological Survey – Thallium
Thallium(I) compounds
Oxides
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