Black 7984, Food Black 2, or C.I. 27755, is a brown-to-black synthetic diazo dye. It is often used as the tetrasodium salt.

Black 7984^[1]

Names
IUPAC name Tetrasodium 6-amino-4-hydroxy-3-[[7-sulfonato-4-[(4-sulfonatophenyl)azo]-1-naphthyl]azo]naphthalene-2,7-disulfonate
Other names Food Black 2 C.I. 27755
Identifiers
CAS Number	2118-39-0 Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.016.661
EC Number	218-326-9
PubChem CID	14047491
CompTox Dashboard (EPA)	DTXSID40879792
InChI InChI=1S/C26H19N5O13S4.4Na/c27-20-12-18-13(9-23(20)47(39,40)41)10-24(48(42,43)44)25(26(18)32)31-30-22-8-7-21(17-6-5-16(11-19(17)22)46(36,37)38)29-28-14-1-3-15(4-2-14)45(33,34)35;;;;/h1-12,30H,27H2,(H,33,34,35)(H,36,37,38)(H,39,40,41)(H,42,43,44);;;;/q;4*+1/p-4/b29-28?,31-25-;;;; Key: XAOPCPOUYMCJFA-PEEPPZCGSA-J
SMILES [O-]S(C(C=C4)=CC=C4/N=N/C(C=C2)=C3C(C=C(S([O-])(=O)=O)C=C3)=C2/N=N/C1=C(S([O-])(=O)=O)C=C(C=C(S([O-])(=O)=O)C(N)=C5)C5=C1O)(=O)=O.[Na+].[Na+].[Na+].[Na+]
Properties
Chemical formula	C26H15N5Na4O13S4
Molar mass	825.63 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

When used as a food dye, it has E number E152. Its use in food has not been permitted in the United States and in the European Union since 1984.^{[citation needed]} It is also not permitted in Australia and Japan.^{[citation needed]}

Black 7984 is also used in cosmetics.