Alizarin

Bahan celup kristal merah dibuat secara sintetik atau dari madder, persenyawaannya dipakai sebagai indikator.

Merriam-Webster Online Dictionary
alizarin (noun)
1.
an orange or red crystalline compound CHO formerly prepared from madder and now made synthetically and used especially to dye Turkey reds and in making red pigments - 14 8 4
2.
any of various acid, mordant, and solvent dyes derived like alizarin proper from anthraquinone
Alizarin (Wikipedia)
"Madder lake" redirects here. For the Australian band, see Madder Lake (band).
Alizarin
Skeletal formula of alizarin
Ball-and-stick model of alizarin
Sample of alizarin
Names
Preferred IUPAC name
1,2-Dihydroxyanthracene-9,10-dione
Other names
1,2-Dihydroxy-9,10-anthracenedione
1,2-Dihydroxyanthraquinone
Turkey red
Mordant red 11
Alizarin B
Alizarin red
Identifiers
3D model (Jmol)
ChEBI
ChemSpider
ECHA InfoCard 100.000.711
KEGG
UNII
Properties
C14H8O4
Molar mass 240.21 g·mol−1
Appearance orange-red crystals or powder
Density 1.540 g/cm3
Melting point 279 to 283 °C (534 to 541 °F; 552 to 556 K)
Boiling point 430 °C (806 °F; 703 K)
slightly to sparingly soluble
Acidity (pKa) 6.94
Hazards
Safety data sheet External MSDS
R-phrases R36 R37 R38
S-phrases S26 S36
Related compounds
Related compounds
anthraquinone, anthracene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Alizarin or 1,2-dihydroxyanthraquinone (also known as Mordant Red 11 and Turkey Red) is an organic compound with formula C
14
H
8
O
4
that has been used throughout history as a prominent red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus. In 1869, it became the first natural pigment to be duplicated synthetically.

Alizarin is the main ingredient for the manufacture of the madder lake pigments known to painters as Rose madder and Alizarin crimson. Alizarin in the most common usage of the term has a deep red color, but the term is also part of the name for several related non-red dyes, such as Alizarine Cyanine Green and Alizarine Brilliant Blue. A notable use of alizarin in modern times is as a staining agent in biological research because it stains free calcium and certain calcium compounds a red or light purple color. Alizarin continues to be used commercially as a red textile dye, but to a lesser extent than 100 years ago.