The Octamethylsilsesquioxane, with cas registry number 17865-85-9, has the systematic name of 1,3,5,7,9,11,13,15-octamethylpentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane. Besides this, it is also called Pentacyclo[9.5.1.1(3,9).1(5,15).1(7,13)]octasiloxane, octamethyl-. This chemical should be stored in cool, dry place.

Physical properties about this chemical are: (1)#H bond acceptors: 12; (2)#H bond donors: 0; (3)#Freely Rotating Bonds: 0; (4)Polar Surface Area: 110.76 Å²; (5)Index of Refraction: 1.475; (6)Molar Refractivity: 119.82 cm³; (7)Molar Volume: 425.5 cm³; (8)Polarizability: 47.5×10^-24cm³; (9)Surface Tension: 22.5 dyne/cm; (10)Enthalpy of Vaporization: 45.26 kJ/mol; (11)Vapour Pressure: 0.0785 mmHg at 25°C.

You can still convert the following datas into molecular structure: 
(1)SMILES: O1[Si]5(O[Si]3(O[Si]4(O[Si](O[Si]2(O[Si](O[Si](O[Si]1(O2)C)(O3)C)(O4)C)C)(O5)C)C)C)C
(2)InChI: InChI=1/C8H24O12Si8/c1-21-9-22(2)12-25(5)14-23(3,10-21)16-27(7)17-24(4,11-21)15-26(6,13-22)19-28(8,18-25)20-27/h1-8H3
(3)InChIKey: SOQGBGSEJYZNPS-UHFFFAOYAS
(4)Std. InChI: InChI=1S/C8H24O12Si8/c1-21-9-22(2)12-25(5)14-23(3,10-21)16-27(7)17-24(4,11-21)15-26(6,13-22)19-28(8,18-25)20-27/h1-8H3
(5)Std. InChIKey: SOQGBGSEJYZNPS-UHFFFAOYSA-N