Iron(II) perchlorate

Iron(II) perchlorate
Names
IUPAC name
Iron(II) diperchlorate
Other names
  • Iron diperchlorate
  • Ferrous perchlorate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.034.263 Edit this at Wikidata
EC Number
  • 237-704-4
  • InChI=1S/2ClHO4.Fe.H2O/c2*2-1(3,4)5;;/h2*(H,2,3,4,5);;1H2/q;;+2;/p-2
    Key: BJDJGQJHHCBZJZ-UHFFFAOYSA-L
  • O.[O-]Cl(=O)(=O)=O.[O-]Cl(=O)(=O)=O.[Fe+2]
Properties
Fe(ClO4)2
Molar mass 254.75 g/mol
Appearance Green crystals
Density 2.15 g/cm3
Melting point 100 °C (212 °F; 373 K)
98 g/100 mL (25 °C)[1]
Structure[2]
Orthorhombic
Pmn21
a = 7.79 Å, b = 13.48 Å, c = 5.24 Å
Hazards
GHS labelling:
GHS03: OxidizingGHS07: Exclamation mark
Danger
H272, H315, H319, H335
P210, P220, P221, P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
2
0
1
OX
Related compounds
Other cations
 Manganese(II) perchlorate
Cobalt(II) perchlorate
Nickel(II) perchlorate
Related compounds
 Iron(III) perchlorate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Iron(II) perchlorate is the inorganic compound with the formula Fe(ClO4)2·6H2O. A green, water-soluble solid, it is produced by the reaction of iron metal with dilute perchloric acid followed by evaporation of the solution:[3]

Fe + 2 HClO4 + 6 H2O → Fe(ClO4)2·6H2O + H2

Although the ferrous cation is a reductant and the perchlorate anion is a strong oxidant, in the absence of atmospheric oxygen, dissolved ferrous perchlorate is stable in aqueous solution because the electron transfer between both species Fe2+ and ClO−4 is hindered by severe kinetic limitations. Being a weak Lewis base, the perchlorate anion is a poor ligand for the aqueous Fe2+ and does not contribute to the electron transfer by favoring the formation of an inner sphere complex giving rise to a possible reorganisation of the activated complex. The resulting high activation energy prohibits a thermodynamically spontaneous redox reaction (∆Gr < 0).

However, in aqueous solution, and under air, iron(II) perchlorate slowly oxidizes to iron(III) oxyhydroxide.[4]

The hexahydrate consists of discreet hexa-aquo-iron(II) divalent cations and perchlorate anions. It crystallizes with an orthorhombic structure.[2] It has minor phase transitions at 245 and 336 K.[5]

  1. ^ Mark W. Zettler; Daniela Sustac Roman (2014). "Iron(II) Perchlorate". Encyclopedia of Reagents for Organic Synthesis (EROS). doi:10.1002/047084289X.ri064.pub2.
  2. ^ a b Ghosh, Minakshi; Ray, Siddhartha (1981). "Twinning, disorder and phase transition in ferrous Perchlorate hexahydrate crystals". Zeitschrift für Kristallographie – Crystalline Materials. 155 (1–2): 129–137. Bibcode:1981ZK....155..129G. doi:10.1524/zkri.1981.155.1-2.129.
  3. ^ B.K. Chaudhuri (1975). "A new type of phase transition in M(ClO4)2(H2O)6 M = Fe, Co, Ni and Mn". Solid State Communications. 16 (6): 767–772. doi:10.1016/0038-1098(75)90071-X.
  4. ^ Philip George (1954). "The oxidation of ferrous perchlorate by molecular oxygen". Journal of the Chemical Society (Resumed): 4349–4359. doi:10.1039/JR9540004349.
  5. ^ D. P. Chiang; C. H. Peng; J. K. Mei; I. M. Jiang; S. C. Lin; Y. C. Chen; H. T. Liu; Y. F. Chen; W. S. Tse (2008). "Raman spectra of crystalline iron perchlorate hexahydrate". Journal of Raman Spectroscopy. 39 (3): 344–348. doi:10.1002/jrs.1801.