Molecular structure of Fluorescein di(beta-D-galactopyranoside) (CAS NO.17817-20-8) is:

Product Name: Fluorescein di(beta-D-galactopyranoside)
CAS Registry Number: 17817-20-8
IUPAC Name: 3',6'-bis[[(2S,3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy]spiro[2-benzofuran-3,9'-xanthene]-1-one
Molecular Weight: 656.58748 [g/mol]  
Molecular Formula: C₃₂H₃₂O₁₅  
XLogP3-AA: -0.2  
H-Bond Donor: 8  
H-Bond Acceptor: 15
Melting Point: 200-203 °C (dec.)
Storage temp.: −20 °C
Index of Refraction: 1.764 
Molar Refractivity: 155.43 cm³ 
Molar Volume: 376.2 cm³
Surface Tension: 112.2 dyne/cm 
Density: 1.74 g/cm³ 
Flash Point: 316.5 °C 
Enthalpy of Vaporization: 148.79 kJ/mol 
Boiling Point: 974.8 °C at 760 mmHg 
Vapour Pressure: 0 mmHg at 25 °C

Safty information about Fluorescein di(beta-D-galactopyranoside) (CAS NO.17817-20-8) is:
Safety Statements: 22-24/25 
S22:Do not breathe dust. 
S24/25:Avoid contact with skin and eyes.
WGK Germany: 3
F: 8

 Fluorescein di(beta-D-galactopyranoside) , its cas register number is 17817-20-8. It also can be called Fluorescein-digalactoside ; Fluorescein-di-beta-D-galactopyranoside ; Fluorescein-di-beta-D-galactoside ;  Spiro(isobenzofuran-1(3H),9'-(9H)xanthen)-3-one, 3',6'-bis(beta-D-galactopyranosyloxy)- .