Magnus's green salt is the
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
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 ...
t(NH3)4PtCl
4]. This salt is named after
Heinrich Gustav Magnus
Heinrich Gustav Magnus (; 2 May 1802 – 4 April 1870) was a notable German experimental scientist. His training was mostly in chemistry but his later research was mostly in physics. He spent the great bulk of his career at the University of Ber ...
, who, in the early 1830s, first reported the compound. The compound is a
linear chain compound, consisting of a chain of platinum atoms. It is dark green, which is unusual for platinum compounds.
Structure
This species has attracted interest in
materials chemistry and
solid-state physics
Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state physics studies how the l ...
because of its one-dimensional structure. It contains a chain of alternating
tCl4sup>2− anions and
t(NH3)4sup>2+ cations, in which the platinum atoms are separated by 3.25 Å. It is a
semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...
.
Preparation
The compound may be prepared by combining aqueous solutions of
t(NH3)4sup>2+ and
tCl4sup>2−, which gives a deep green solid precipitate. Under some conditions, this reaction affords a pink
polymorph of Magnus's green salt. In this so-called "Magnus's pink salt", the square planar Pt complexes are not stacked.
Related compounds
Magnus's green salt has the same
empirical formula
In chemistry, the empirical formula of a chemical compound is the simplest whole number ratio of atoms present in a compound. A simple example of this concept is that the empirical formula of sulfur monoxide, or SO, would simply be SO, as is th ...
as
''cis''-PtCl2(NH3)2 ("Peyrone chloride") and
''trans''-PtCl2(NH3)2. These cis and trans compounds are molecules, whereas Magnus's green salt is a polymer. This difference is manifested by the solubility of the molecular complexes in water, whereas Magnus's green salt is insoluble.
Soluble analogues of Magnus's green salt can be prepared by replacing the ammonia with ethylhexylamine.
The corresponding palladium compound (
d(NH3)4PdCl4 is known as "
Vauquelin’s salt".
History
Magnus's green salt was one of the first examples of a
metal ammine complex
In coordination chemistry, metal ammine complexes are metal complexes containing at least one ammonia () ligand. "Ammine" is spelled this way due to historical reasons; in contrast, alkyl or aryl bearing ligands are spelt with a single "m". Almost ...
.
References
{{DEFAULTSORT:Magnus's green salt
Platinum(II) compounds
Metal halides
Ammine complexes
Chloro complexes
Inorganic polymers