Colour geraniums

Markham, K.R., Mitchell, K.A., and Boase, M.R., Malvidin-3-0-glucoside-5-0-(6-acetylgluco-side) and its colour manifestation in Johnson s Blue and other Blue geraniums. Phytochemistry, 45, 417, 1997. 

Lewisite is an odorless, colourless oily liquid of structural formula ClCH-CHAsC12 (Table 2). Lewisite is said to darken on standing and the technical material is often blue-black to black in colour and is said to smell of geraniums. Lewisite, which is not soluble in water to... 

The disodium salt of 2, 4, 5, 7 -tetraiodofluorescein, erythrosine, is listed by the Colour Index (1971) as Cl 45430/Acid Red 51 and Cl 45430 1/Pigment Red 172 as the aluminium salt. It was discovered by Kussmaul in 1876 (Colour Index, 1971). Sources such as Weber (1923) and Heaton (1928) say that, along with eosin and related dye compounds, it was used to form lake pigments such as that commonly known as geranium lake (qq.v.). 

Figure 21.5 The red petals of pelargonium (geranium) contain the dye pelargonidin. Hydrogen ions or hydroxide ions can make small changes in its molecular structure to produce different colours.

The pure compound is a colourless oily hquid. The industrially produced compound may be amber to dark brown-coloured with a strong smell of geraniums. 

Liquid glycerine soap of the consistency of syrup is at present a much sought after toilet adjunct, and is mostly coloured with pale brown (honey glycerine soap) or with pale pink aiid perfumed with geranium oil (rose glycerine soap) and supplied to the trade. 

---