Hi David,

Prussian Blue was I think the first modern synthetic pigment made, first done in about 1705-6.  It’s iron with CN cyano (not cyanide) groups tightly bound to the iron [Fe7(CN)18]. The cyano groups are so tightly bound that it is completely non-toxic. This is the blue used in blueprints and fountain pen inks. It’s also what’s in Engineer’s Blue use for scraping reference surfaces very flat.

I think you may have noticed by now I have quite some interest in the chemistry of painting and decorating :-)

Andrew



On 16/02/2016, 12:11, "Harpsichords and Related Topics on behalf of Kelzenberg, David C" <[log in to unmask] on behalf of [log in to unmask]> wrote:

(Wasn't there cyanide or "Prussian blue" in some blue and green pigments too? 


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