Table 6: Bond distances for 1, X2.

Atom 1Atom 2Distance (Å)

Si1O11.609 (3)
Si1O41.626 (3)
Si1O61.615 (2)
Si1C41.828 (5)
Si2O21.614 (3)
Si2O31.630 (3)
Si2O71.620 (3)
Si2C11.840 (4)
Si3O31.621 (3)
Si3O41.601 (3)
Si3O71.608 (3)
Si4O11.612 (3)
Si4O21.620 (3)
Si4O51.611 (3)
Si4C31.848 (5)
Si3C21.819 (4)