Formula H12Cl4N4Pt2 Density 3.7 g/cm³ Appearance green solid | Molar mass 600.09 g/mol Melting point 320 °C | |
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Magnus' green salt is the inorganic compound with the formula [Pt(NH3)4][PtCl4]. This salt is named after Heinrich Gustav Magnus, who, in the early 1830s, first reported the compound. The compound is interesting to chemists because it has an unusual structure, consisting of a chain of Pt atoms, and it exhibits unusual properties, being dark green, which is very unusual for platinum compounds.
Contents
Structure
This species has been of interest in materials chemistry and solid-state physics because of its one-dimensional structure. It contains a linear chain of alternating [PtCl4]2− anions and [Pt(NH3)4]2+ cations, in which the platinum atoms are separated by 3.25 Å. It is a semi-conductor.
Preparation
The compound may be prepared by combining aqueous solutions of [Pt(NH3)4]2+ and [PtCl4]2−, which gives a deep green solid precipitate.
Related compounds
Magnus' green salt has the same empirical formula as cis-PtCl2(NH3)2 ("Peyrone chloride") and trans-PtCl2(NH3)2. These cis and trans compounds are molecules, whereas Magnus' green salt is a polymer. This difference is manifested by the solubility of the molecular complexes is water, whereas Magnus' green salt is insoluble.
Soluble analogues of Magnus' green salt can be prepared by replacing the ammonia with ethylhexylamine.
The corresponding palladium compound ([Pd(NH3)4PdCl4]) is known as "Vauquelin’s salt".
History
Magnus' green salt was one of the first examples of a metal ammine complex. Ammonia species are very common now: they were the basis of Alfred Werner's discoveries.