Blue

On this page is information about blue colours. These are:

• Ultramarine (Synthetic Lazurite)
• Smalt / Royal Blue
• Chessylite / Azurite
• Cobalt Blue
• Cerulean Blue
• Prussian Blue
• Indigo
• Egyptian Blue
• Lazurite
• Posnjakite
• Phthalocyanine

Ultramarine (Synthetic Lazurite)

Use - Paint pigment, plastics pigment

Formula - Na_8-x[AlSiO₄]₆[S₃, S₂]_2-2x

Chemical Name - Synthetic Lazurite

Structure - Cubic

Synthesis - Kaolin, silica, sodium sulfte, sodium carbonate, sulfur and charcoal are heated in a furnace. The mixture is cooled and controlled oxidation performed before being cooled to room temperature, powdered and then dried.

Interesting Facts - Ultramarine blue has been used in washing powders, and is a safe blue compound. Blue plastic bottles are coloured with ultramarine pigment.

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Smalt / Royal Blue

Use - Colouring glass and as a paint pigment

Formula - Co₂SiO₄

Chemical Name - Cobalt(II) silicate

Structure - Cubic

Synthesis - Silica, potash, cobalt oxide and alumina are heated to a moderate temperate. The mixture is cooled and ground into a fine powder.

Interesting Facts - n/a

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Chessylite / Azurite

Use - Paint pigment

Formula - 2CuCO₃ • Ca(OH)₂

Chemical Name - Copper(II) carbonate - copper(II)hydroxide

Structure - Monoclinic

Synthesis - Naturally occuring mineral

Interesting Facts - n/a

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Cobalt Blue

Use - Paint pigment

Formula - CoO • Al₂O₃

Chemical Name - Cobalt(II) oxide - aluminium oxide

Structure - Cubic

Synthesis - Heat a mixture of cobalt oxide and aluminium chloride.

Interesting Facts - n/a

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Cerulean Blue

Use - Paint pigment

Formula - CoO • nSnO₂

Chemical Name - Cobalt(II) stannate

Structure - n/a

Synthesis - Tin oxide is added to an aqueous solution of cobalt nitrate and heated. Alternatively mix a solution of postassium stannate and cobalt chlordie, then wash and heat the precipitate.

Interesting Facts - n/a

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Prussian Blue

Use - Paint pigment

Formula - Fe₄[Fe(CN)₆]₃

Chemical Name - Iron(III) hexacyanoferrate

Structure - Cubic

Synthesis - Mix postassium cyanoferrate and iron chloride solutions. Dry and grind the resultant precipitate.

Interesting Facts - Discovered in 1710 by a colour maker in Berlin called Diesbach.

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Indigo

Use - Paint pigment or dye for clothes

Formula - C₁₆H₁₀N₂O₂

Chemical Name - 2,2-biindolingliden-3,3-dione

Structure - n/a

Synthesis - Soak, ferment,dry and then grind the indigofera tirctoria shrub.

Interesting Facts - In 1890 £4 000 000 worth of the indgofera tirctoria plant was imported from india.

Indigo was also used to dye the bandages used to mummify the dead in ancient Egypt. It was also used 2700 years ago by the Babylonians in Mesopotamia.

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Egyptian Blue

Use - Paint pigment

Formula - CaCuSi₄O₁₀

Chemical Name - Calcium copper(II) silicate

Structure - Tetragonal

Synthesis - Heat a mixture of 4 parts silicon dioxide to one part calcium oxide and one part copper oxide to 900°C using a borax flux. Then maintain the mixture at 800°C for at least 10 hours.

Interesting Facts - Was originally made by the ancient Egyptians.

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Lazurite

Use - Paint pigment

Formula - Na_8-x[AlSiO₄]₆[S₃, S₂]_2-2x

Chemical name - Lazurite

Structure - Cubic

Synthesis - From the mineral Lazurite

Interesting Facts - The best Lazurite is mined in Afghanistan. Lazurite was first used in around 600AD. The cost was so expensive that only very important paintings were created using Lazurite.

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Poznjakite

Use - Paint pigment

Formula - CuSO₄ • 3Ca(OH)₂ • H₂O

Chemical Name - Basic copper(II) sulfate

Structure - Monoclinic

Synthesis - From mineral deposits.

Interesting Facts - n/a

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Phthalocyanine

Use - Solvent dye

Formula - [C₃₂H₁₆N₈]^2-

Chemical Name - Tetrabenzoporphyracin

Structure - Complex conjugated structure

Synthesis - n/a

Interesting Facts - Used to produce the coloures direct blue 86, 199, 38 and 48. Also used to produce phthalocyanine blue and green.

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