Magnus' green salt
|Molar mass||600.09 g/mol|
|Melting point||320 °C (608 °F; 593 K)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
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 has an unusual structure, consisting of a chain of platinum atoms, and it exhibits unusual properties, being dark green, which is very unusual for platinum compounds.
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.
The compound may be prepared by combining aqueous solutions of [Pt(NH3)4]2+ and [PtCl4]2−, which gives a deep green solid precipitate. Under some conditions, this reaction affords a pink polymorph of Magnus' green salt. In this so-called "Magnus' pink salt, the square planar Pt complexes are not stacked.
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.
The corresponding palladium compound ([Pd(NH3)4PdCl4]) is known as "Vauquelin’s salt".
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- Bremi, J.; Caseri, W. & Smith, P. (2001). "A new compound derived from Magnus' green salt: solid state structure and evidence for platinum chains in solution". J. Mater. Chem. 11 (10): 2593–2596. doi:10.1039/b104675f.