Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- List of symbols and units
- List of abbreviations and acronyms
- 1 Introduction to electrochromism
- 2 A brief history of electrochromism
- 3 Electrochemical background
- 4 Optical effects and quantification of colour
- 5 Kinetics of electrochromic operation
- 6 Metal oxides
- 7 Electrochromism within metal coordination complexes
- 8 Electrochromism by intervalence charge-transfer coloration: metal hexacyanometallates
- 9 Miscellaneous inorganic electrochromes
- 10 Conjugated conducting polymers
- 11 The viologens
- 12 Miscellaneous organic electrochromes
- 13 Applications of electrochromic devices
- 14 Fundamentals of device construction
- 15 Photoelectrochromism
- 16 Device durability
- Index
- Plate Section
- References
8 - Electrochromism by intervalence charge-transfer coloration: metal hexacyanometallates
Published online by Cambridge University Press: 10 August 2009
- Frontmatter
- Contents
- Preface
- Acknowledgements
- List of symbols and units
- List of abbreviations and acronyms
- 1 Introduction to electrochromism
- 2 A brief history of electrochromism
- 3 Electrochemical background
- 4 Optical effects and quantification of colour
- 5 Kinetics of electrochromic operation
- 6 Metal oxides
- 7 Electrochromism within metal coordination complexes
- 8 Electrochromism by intervalence charge-transfer coloration: metal hexacyanometallates
- 9 Miscellaneous inorganic electrochromes
- 10 Conjugated conducting polymers
- 11 The viologens
- 12 Miscellaneous organic electrochromes
- 13 Applications of electrochromic devices
- 14 Fundamentals of device construction
- 15 Photoelectrochromism
- 16 Device durability
- Index
- Plate Section
- References
Summary
Prussian blue systems: history and bulk properties
Prussian blue – PB; ferric ferrocyanide, or iron(III) hexacyanoferrate(II) – first made by Diesbach in Berlin in 1704, is extensively used as a pigment in the formulation of paints, lacquers and printing inks. Since the first report in 1978 of the electrochemistry of PB films, numerous studies concerning the electrochemistry of PB and related analogues have been made, with, in addition to electrochromism, proposed applications in electroanalysis and electrocatalysis. Fundamental studies on basic PB properties (electronic structure, spectra and conductimetry) underlie the elaborations that follow.
Prussian blue is the prototype of numerous polynuclear transition-metal hexacyanometallates, which form an important class of insoluble mixed-valence compounds. They have the general formula M′k[M″(CN)6]l (k, l integral) where M′ and M″ are transition metals with different formal oxidation numbers. These materials can contain ions of other metals and varying amounts of water. In PB the two transition metals in the formula are the two common oxidation states of iron, FeIII and FeII. Prussian blue is readily prepared by mixing aqueous solutions of a hexacyanoferrate(III) salt with iron(II), the preferred industrial-production route (rather than iron(III) with a hexacyanoferrate(II) salt). In the PB chromophore, the distribution of oxidation states is FeIII–FeII respectively; i.e. it contains Fe3+ and [FeII(CN)6]4−, as established by the CN stretching frequency in the IR spectrum and confirmed by Mössbauer spectroscopy. The chromophore alone thus has a negative charge, therefore in the solid a counter cation is to be incorporated.
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- Electrochromism and Electrochromic Devices , pp. 282 - 302Publisher: Cambridge University PressPrint publication year: 2007
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