Aluminon

Aluminon
Other names ammonium aurin-tricarboxylate; 5-[(3-carboxy-4-hydroxyphenyl)(3-carboxy-4-oxo-2,5-cyclohexadien-ylidene)methyl]-2-hydroxybenzoic acid triammonium salt
Identifiers
CAS number	569-58-4
PubChem	2734958
ChemSpider	2016698 Y
Jmol-3D images	Image 1
SMILES O=C([O-])\C1=C\C(\C=C/C1=O)=C(\c2ccc(O)c(C([O-])=O)c2)c3ccc(O)c(C([O-])=O)c3.[NH4+].[NH4+].[NH4+]
InChI InChI=1S/C22H14O9.3H3N/c23-16-4-1-10(7-13(16)20(26)27)19(11-2-5-17(24)14(8-11)21(28)29)12-3-6-18(25)15(9-12)22(30)31;;;/h1-9,23-24H,(H,26,27)(H,28,29)(H,30,31);3*1H3 Y Key: AIPNSHNRCQOTRI-UHFFFAOYSA-N Y InChI=1/C22H14O9.3H3N/c23-16-4-1-10(7-13(16)20(26)27)19(11-2-5-17(24)14(8-11)21(28)29)12-3-6-18(25)15(9-12)22(30)31;;;/h1-9,23-24H,(H,26,27)(H,28,29)(H,30,31);3*1H3 Key: AIPNSHNRCQOTRI-UHFFFAOYAI
Properties
Molecular formula	C22H23N3O9
Molar mass	473.43 g/mol
Appearance	yellow-brown crystals, red in aqueous solution
Solubility in other solvents	freely soluble in H2O
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Aluminon, the triammonium salt of aurintricarboxylic acid, is a dye commonly used to detect the presence of the aluminium ion in an aqueous solution. In addition to its use in qualitative inorganic analysis, aluminon has applications in pharyngeal aerosols. It forms brilliantly colored lake pigments with aluminum, chromium, iron, and beryllium.

Aluminon is prepared by reacting sodium nitrite with salicylic acid, adding formaldehyde, then treating with ammonia.

See also

• Analytical chemistry
• Colorimetry