A composition selected from the group consisting of bis(tert-butoxy)(isopropoxy)silanol, bis(isopropoxy)(tert-butoxy)silanol, bis(tert-pentoxy)(isopropoxy)silanol, bis(isopropoxy)(tert-pentoxy)silanol, bis(tert-pentoxy)(tert-butoxy)silanol, bis(tert-butoxy)(tert-pentoxy)silanol and mixtures thereof; its use to form a metal or metalloid silicate layer on a substrate and the synthesis of the mixed alkoxysilanols.