Silanols

Acidity

Silanols are more acidic than the corresponding alcohols. This trend contrasts with the fact that Si is far less electronegative than carbon (1.90 vs 2.55, respectively). For Et₃SiOH, the pK_a is estimated at 13.6 vs. 19 for tert-butyl alcohol. The pK_a of 3−ClC₆H₄)Si(CH₃)₂OH is 11. Because of their greater acidity, silanols can be fully deprotonated in aqueous solution, especially the arylsilanols. The conjugate base is called a siloxide or a silanolate.