Sodium Silicate random network

Question 1

What are bridging oxygens?

Answer 1

~ oxygens bonded to two Si4+ ions (between two SiO4(4-) tetrahedra)

Question 2

What are non bridging oxygens?

Answer 2

~ oxygen anions ionically bond to Na+, don’t form a bridge between two Si4+ ions

Question 3

What are network formers?

Answer 3

~ Si4+

Question 4

What are network modifiers?

Answer 4

~ Na+
~ these ions cluster together
~ easily rearrange, transforms bridging oxygens into NBO
~ makes manufacturing easier
~ the glass will be fluid at a lower temp

Question 5

What is a flux?

Answer 5

~ Na2O
~ substantially lowers melting temp of silica

Question 6

Why is Na2O-SiO2 not used as a commercial glass?

Answer 6

~ the glass is water soluble
~ Na+ ion exchanges with water, everything falls apart