IUPAC Name: 1-4-dioxane-2-5-dione 
Empirical Formula: C₄H₄O₄
Molecular Weight: 116.0722g/mol
EINECS: 207-954-9 
Structure of 1-4-dioxane-2-5-dione (CAS NO.502-97-6):

Index of Refraction: 1.45
Molar Refractivity: 21.91 cm³
Molar Volume: 81.5 cm³
Polarizability: 8.68×10^-24cm³
Surface Tension: 45.3 dyne/cm
Density: 1.423 g/cm³
Flash Point: 181.5 °C
Enthalpy of Vaporization: 56.43 kJ/mol 
Physical Appearance: 81-83°C
Boiling Point: 322.5 °C at 760 mmHg
Vapour Pressure: 0.000279 mmHg at 25°C 
Classification Code: TSCA Flag P [A commenced PMN (Premanufacture Notice) substance] 
Canonical SMILES: C1C(=O)OCC(=O)O1
InChI: InChI=1S/C4H4O4/c5-3-1-7-4(6)2-8-3/h1-2H2
InChIKey: RKDVKSZUMVYZHH-UHFFFAOYSA-N

Hazard Codes: Xi,Xn
Risk Statements: 36/37/38-36-22
R36/37/38:Irritating to eyes, respiratory system and skin. 
R22:Harmful if swallowed.
Safety Statements: 22-24/25-37/39-26 
S22:Do not breathe dust. 
S24/25:Avoid contact with skin and eyes. 
S37/39:Wear suitable gloves and eye/face protection. 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.

  1-4-dioxane-2-5-dione , its cas register number is 502-97-6. It also can be called EINECS 207-954-9 ; Glycolide ;
 Glycollide ; NSC 403079 ; p-Dioxane-2,5-dione (8CI) . 1-4-dioxane-2-5-dione (CAS NO.502-97-6) is irritating to eyes, respiratory system and skin and it's harmful if swallowed.