6834-92-0,Sodium metasilicate,"How can a liquid become a gel without freezing?
In alkaline sodium metasilicate solution, silicate species remain dispersed. Lower the pH and Si-OH groups can condense to form Si-O-Si bridges.
As these bridges multiply, an extended silica-rich network develops. Eventually it spans the liquid and traps water in its pores: a gel has formed.
The liquid stops flowing not because it froze, but because a microscopic inorganic network grew throughout it.
Global Chemical Database