Gold chalcogenides are compounds formed between
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...
and one of the
chalcogen
The chalcogens (ore forming) ( ) are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioac ...
s, elements from
group 16
The chalcogens (ore forming) ( ) are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioa ...
of the
periodic table
The periodic table, also known as the periodic table of the (chemical) elements, is a rows and columns arrangement of the chemical elements. It is widely used in chemistry, physics, and other sciences, and is generally seen as an icon of ch ...
:
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 wel ...
,
sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
,
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, ...
, or
tellurium
Tellurium is a chemical element with the symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionall ...
.
*
Gold(III) oxide, Au
2O
3. Decomposes into gold and oxygen above 160 °C, and dissolves in concentrated alkalis to form solutions which probably contain the
4">u(OH)4sup>− ion
*
Gold(I) sulfide
Gold(I) sulfide is the inorganic compound with the formula . It is the principal sulfide of gold. It decomposes to gold metal and elemental sulfur, illustrating the "nobility" of gold.
Structure and preparation
The compound crystallizes in the mot ...
, Au
2S. Formed by passing
hydrogen sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...
through solutions of gold(I) compounds.
*
Gold(III) sulfide
Gold(III) sulfide or auric sulfide is an inorganic compound with the formula .Auric sulfide has been described as a black and amorphous. Little evidence has been published supporting the existence of macroscopic quantities of this material.
Clai ...
, Au
2S
3, unstable in the presence of water.
*Gold tellurides: Au
2Te
3, Au
3Te
5, and AuTe
2 (approximate formulæ) are known as
non-stoichiometric compound
In chemistry, non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having elemental composition whose proportions cannot be represented by a ratio of small natural numbers (i.e. an empirical formula); m ...
s. They show
metallic conductivity. One telluride of gold is a
superconductor at very low temperatures: Au
3Te
5 (1.62 K).
Natural gold tellurides, like
calaverite
Calaverite, or gold telluride, is an uncommon telluride of gold, a metallic mineral with the chemical formula AuTe2, with approximately 3% of the gold replaced by silver. It was first discovered in Calaveras County, California in 1861, and was ...
and
krennerite
Krennerite is an orthorhombic gold telluride mineral which can contain variable amounts of silver in the structure. The formula is AuTe2, but specimen with gold substituted by up to 24% with silver have been found ( u0.77Ag0.24e2). Both of the c ...
(AuTe
2),
petzite
The mineral petzite, Ag3 Au Te2, is a soft, steel-gray telluride mineral generally deposited by hydrothermal activity. It forms isometric crystals, and is usually associated with rare tellurium and gold minerals, often with silver, mercury, ...
( Ag
3AuTe
2), and
sylvanite (AgAuTe
4), are minor ores of gold (and tellurium). See
telluride mineral
A telluride mineral is a mineral that has the telluride anion as a main component.
Tellurides are similar to sulfides and are grouped with them in both the Dana and Strunz mineral classification systems.http://webmineral.com/strunz/II.shtml Webm ...
s for more information on individual naturally occurring tellurides.
References
*
Gold compounds
Non-stoichiometric compounds
Sulfides
Tellurides
{{inorganic-compound-stub
Transition metal oxides