Magnus' green salt

Magnus' green salt
IUPAC name Tetraammineplatinum(II) tetrachloroplatinate(II)
Identifiers
CAS number	13820-46-7
	Properties
Molecular formula	H12Cl4N4Pt2
Molar mass	600.09 g/mol
Appearance	green solid
Density	3.7 g/mL
Melting point	320 °C; 608 °F; 593 K
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Magnus' green salt is the chemical compound with the formula [Pt(NH₃)₄][PtCl₄]. 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.^[1] It is a semi-conductor. The compound may be prepared by mixing aqueous solutions of [Pt(NH₃)₄]²⁺ and [PtCl₄]²⁻, to obtain a deep green precipitate.^[2] This salt was discovered by Heinrich Gustav Magnus in the early 1830s. The corresponding palladium compound ([Pd(NH₃)₄PdCl₄] is known as "Vauquelin’s salt".

Soluble analogues of the salt can be prepared by replacing the ammonia with ethylhexylamine.^[3][4]

History

Magnus' green salt was one of the first examples of a metal ammine complex. Ammonia species are very common now; they were, after all, the basis of Alfred Werner's discoveries. 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.

References

1. ↑ Atoji, M.; Richardson, J. W.; Rundle, R. E. (1957). "On the Crystal Structures of the Magnus Salts, Pt(NH₃)₄PtCl₄". J. Am. Chem. Soc. 79 (12): 3017–3020. doi:10.1021/ja01569a009. 
2. ↑ R. N. Keller "Tetrammineplatinum(II) Chloride: (Tetrammineplatinous Chloride)" Inorganic Syntheses, 1946, vol.2 , p 250–253.doi:10.1002/9780470132333.ch80
3. ↑ Caseri, W. (2004). "Derivatives of Magnus' green salt; from intractable materials to solution-processed transistors". Platinum Metals Rev. 48 (3): 91–100. doi:10.1595/147106704X1504. 
4. ↑ Bremi, J.; Caseri, W. and 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.