A composition for forming an insulating film comprising at least one of a compound represented by formula (I), a hydrolysate of the compound represented by formula (I) and a condensate of the compound represented by formula (I): ##STR00001## wherein R.sup.1 to R.sup.7 each independently represents an organic group, and R.sup.1 to R.sup.7 are the same or different. And an insulating film obtained by a process, the process comprising using the compound represented by formula (I) as a starting material.