Turnbull s blue

Prussian Blue. Reaction of [Fe(CN)3] with an excess of aqueous h on(Ill) produces the finely divided, intensely blue precipitate Pmssian Blue [1403843-8] (tetrairon(Ill) tris(hexakiscyanoferrate)), Fe4[Fe(CN)3]. Pmssian Blue is identical to Turnbull s Blue, the name which originally was given to the material produced by reaction of [Fe(CN)3] with excess aqueous h on(Il). The soHd contains or has absorbed on its surface a large and variable number of water molecules, potassium ions (if present in the reaction), and h on(Ill) oxide. The h on(Il) centers are low spin and diamagnetic h on(Ill) centers are high spin. Variations of composition and properties result from variations in reaction conditions. Rapid precipitation in the presence of potassium ion affords a colloidal suspension of Pmssian Blue [25869-98-1] which has the approximate composition KFe[Fe(CN)3]. Pmssian Blue compounds are used as pigments in inks and paints and its formation on sensitized paper is utilized in the production of blueprints. 

Idiochromatic examples of this are black magnetite [1309-38-2] Fe O otherwise written as Fe(II)0 Fe2(111)02 and the analogous red Mn O and the pigments Pmssian blue [14038-43-8] and Turnbull s blue [25869-98-17, both Fe4(III)[Fe(II)(CN)2]2. Allochromatic examples are widespread in the mineral field, with Fe + + Fe + being involved in blue and green tourmaline [1317-93-7] blue iolite (cordierite) [12182-53-5] etc. 

Since ferrous iron usually colors minerals green, and ferric iron yellow or brown, it may seem rather remarkable that the presence of both together should give rise to a blue color, as in the case of vivianite. It may be pointed out, however, that this is by no means a unique instance of such an effect. Even apart from the artificial substances, Prussian and Turnbull s blues, which are complex cyanides containing both ferric and ferrous iron, there are several blue minerals in which the color seems explainable only on this basis. The most noteworthy of these are crocidolite and related amphiboles iolite and the blue tourmaline or indicolite. Other instances may perhaps be discovered, should this subject ever be investigated as it deserves to be . 

Green precipitate, turns brown on exposure to air White precipitate, rapidly turning blue Dark blue precipitate (Turnbull s blue)... 

The stabilization of Fe by 1,4,7-triathiacyclononane, ([9]-ane-S3, ttcn= (297), has permitted the preparation of the first authentic example of a Turnbull s Blue, i.e., an iron(II)-hexacyano-ferrate(lll) combination, in the form of [Fe(ttcn)2][Fe(CN)6] 2H20. This so-called Ukrainian Red, named in honor of the country of origin of several of the authors, is a valence-trapped (Robin and Day class compound. The redox potential for the [Fe(ttcn)2] " couple is... 

A similar substance, known as Turnbull s blue, is obtained as a blue precipitate by adding an iron(II) salt to a solution of potassium ferricyanide. Iron(ll) is oxidized to iron(III) by ferricyanide ion, the latter is reduced to ferrocyanide ... 

The precipitate formed by adding a solution of femdeyanide of potassium—the red prussiate—to a protosalt of iron, constitutes the odor known in commerce as Turnbull s blue. It is produced by the substitution of three atoms of iron for the three of potassium in the red salt. Its color is a little brighter than common prussian blue. It is prepared in the arts by adding to a solution of copperas a mixture of yellow prussiate of potassa and chloroxide of sodium,... 

The term iron blue pigments as defined in ISO 2495 has largely replaced a great number of older names (e.g., Paris blue, Prussian blue, Berlin blue, Milori blue, Turnbull s blue, toning blue, and nonbronze blue). These names usually stood for insoluble pigments based on microcrystalline Fe(II)Fe(III) cyano complexes many were associated with specific hues. A standardized naming system has been demanded by users and welcomed by manufacturers, and has led to a reduction in the number of varieties [3.177],... 

Addition of ferrous salts to ferricyanides produces Turnbull s blue ... 

In addition to the ignition agents listed in the table, the following may be used Se and BaOz with either BkPdr, ground smokeless powder or Turnbull s Blue zirconium with BaOz ot BkPdr+ NC(ca 12.7%N) + NS... 

FeS04, dark blue precipitate—Turnbull s blue, Fe3 Fe(CN)6 2, insoluble in acids, decomposed by KOH. 

Fig. 9.2 A-C Adjacent sections of field CA1, from a rat 4 weeks post-kainate injection. A is a section stained with Perl s stain, showing an increase in the number of ferric iron positive cells (arrows) in the degenerating CA field (see Fig. 9.1 A). B is a section stained with Turnbull s blue stain, showing an increase in ferrous iron positive cells (arrows) in the degenerating CA field (see Fig. 9.IB). C is a ferritin immunostained section, showing an increased number of ferritin positive cells (arrows). D-F adjacent sections of field CA1, from a rat 8 weeks post-kainate injection. D is a section stained with Perl s stain, showing an increase in the number of ferric iron positive cells, compared to 4 weeks post-injection (see A). E is a section stained with Turnbull s blue, showing an increase in the number of ferrous iron-containing cells, compared to 4 weeks post-injection (see B). F is a ferritin-stained section, showing a decrease in the number of ferritin positive cells (arrows) compared to 4 weeks post-injection (see C). The spherical, heavily ferric or ferrous iron-laden cells shown in D and E are unlabeled for ferritin. Scale=50 /xm. Reproduced with kind permission from Huang and Ong (2005) Experimental Brain Research 161 502-511. Springer.

Turnbull s blue 2KFe"Fe "(CN)6.Aq + Fe"S04.Aq = Fe"3Fe" 2(CN),2 and with excess of a ferric salt, Prussian blue is formed 3lvFe"Fe" (CN)fi.Aq + Fe" Cl3. Aq = Fe 3Fe" 4(CN) 1S + 3 KC1. Aq. Potassium ferricyanide, with ferric iron, gives a brown solution, which may contain ferric cyanide. These colours are used as tests for ferric or ferrous iron. 

Iron Blue is the ISO designation (ISO 2495) for iron cyanide blue pigments of various composition, which are also known as Berlin Blue, Turnbull s Blue, Prussian Blue, Vossen Blue , Milori Blue, Paris Blue, French Blue, China Blue, Bronze Blue, Steel Blue, Ink Blue, among others. 

It was with support of the Mosbauer spectroscopy327 that a long-lasting argument could be decided 328,329 Turnbull s Blue, Fe3[Fe(CN)6]2, is actually the same as Berlin Blue, Fe4[Fe(CN)6]3, even if the summation formulas suggest they are different. As a matter of fact, the summation formula of Berlin Blue is closest to the reality In the ideal Iron Blue crystal, 16 molecules of coordination water are included ... 

The literature does not, however, mention this Iron Blue sample as Prussian Blue , like the others, since it was, at that time, considered to be of another type, i. e., Turnbull s Blue or ferrous ferricyanide ... 

Dark blue precipitate, called Turnbull s blue Deep red bivalent cation [Fe F NJJ2 formed with iron (II) salts in mineral acid solution sensitivity, 0.3 pg Red, iron (II) dimethylglyoxime nickel, cobalt, and large quantities of copper salts interfere sensitivity, 0.04 pg Red coloration due to the complex cation [Fe(C12H8N2)3]2, in slightly acidic conditions... 

Ferrocyanide blue occurs in various shades known as Prussian blue, Chinese blue, muon blue, bronze blue, Antwerp blue, and Turnbull s blue. These names have lost much of their original differentiation the more general term iron blues is preferred. 

DP Turnbull s Blue Test (Arb. Units) Infrared, (A OD) Infrared Crystallinity Index... 

---