Orcein, also  archil, orchil, lacmus, litmus, Citrus Red 2, and C.I. Natural Red 28, are names for dyes extracted from several species of lichen, and it also can be called orchella weeds, it can be found in various parts of the world. The manufacture was described by Cocq in 1812 and in the UK in 1874.

The Orcein, with the CAS registry number 1400-62-0, is also known as 2,8-Bis[(2,4-dihydroxy-6-methylphenyl)amino]-1,9-dimethyldibenzo[b,d]furan-3,7-dione. It belongs to the product categories of Organic matters.This chemical's molecular formula is C₂₈H₂₄N₂O₇ and molecular weight is 500.50. What's more,Its systematic name is Orcein.It is a dark brown crystals or powder.It is harmful if swallowed.When you use it ,wear suitable gloves and eye/face protection.In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.

Physical properties about Orcein are:
(1)ACD/LogP:  3.13; (2)# of Rule of 5 Violations:  2; (3)ACD/LogD (pH 5.5):  3.13; (4)ACD/LogD (pH 7.4):  3.12; (5)ACD/BCF (pH 5.5):  140.88; (6)ACD/BCF (pH 7.4):  138.74; (7)ACD/KOC (pH 5.5):  1201.50; (8)ACD/KOC (pH 7.4):  1183.29; (9)#H bond acceptors:  9; (10)#H bond donors:  6; (11)#Freely Rotating Bonds:  8; (12)Index of Refraction:  1.764; (13)Molar Refractivity:  132.529 cm³; (14)Molar Volume:  320.677 cm³; (15)Surface Tension:  88.2200012207031 dyne/cm; (16)Density:  1.561 g/cm³; (17)Flash Point:  424.918 °C; (18)Enthalpy of Vaporization:  117.324 kJ/mol; (19)Boiling Point:  778.99 °C at 760 mmHg; (20)Vapour Pressure:  0 mmHg at 25°C.

You can still convert the following datas into molecular structure:
(1)SMILES:O=C3/C=C1/O\C\4=C\C(=O)\C(=C(/C/4=C1/C(=C3/Nc2c(cc(O)cc2O)C)C)C)Nc5c(cc(O)cc5O)C;
(2)Std. InChI:InChI=1S/C28H24N2O7/c1-11-5-15(31)7-17(33)25(11)29-27-13(3)23-21(9-19(27)35)37-22-10-20(36)28(14(4)24(22)23)30-26-12(2)6-16(32)8-18(26)34/h5-10,29-34H,1-4H3;
(3)Std. InChIKey:VPEASJIRGSVXBF-UHFFFAOYSA-N.

The toxicity data of Orcein as follows: