Intermediate Topic 643 of 1102 Inorganic Chemistry
Glass
An amorphous solid made by fusing silica with soda and lime.
In-depth explanation of Glass
Glass is an amorphous solid, a supercooled liquid without the long-range order of a crystal. Soda-lime glass is made by fusing silica with sodium carbonate, which lowers the melting point, and calcium carbonate, which improves durability. Na+ ions break up the silicate network by binding to non-bridging oxygen atoms, so the melt can be shaped at a manageable temperature. Borosilicate glass, which contains boron oxide, has a low coefficient of thermal expansion and resists thermal shock, as in Pyrex. Metal oxides are added to give colours.
Going deeper: Glass
Key ideas: Typical soda-lime glass: about 70 percent SiO2, 15 Na2O and 10 CaO, made from sand, soda ash and limestone melted near 1500 C. It is an amorphous supercooled liquid with a softening range rather than sharp melting point. Borosilicate (Pyrex) has B2O3 and low thermal expansion; lead glass has a high refractive index; cobalt gives blue, Cr green, Fe(II) pale green, Cu(I) red colors.
Common mistakes and connections: Students describe glass as a slow-flowing liquid at room temperature; old windows differ in thickness from manufacturing, not flow. Annealing is needed to remove internal stress. Soda-lime glass is soluble slightly in strong base, so alkali bottles etch stoppers. Links to silicates, amorphous solids, and colored ions in transition metals.
Visualization of Glass
Glass keeps the disordered arrangement of a liquid when cooled; with no long-range crystal order it is an amorphous solid. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Adding cobalt oxide to a glass melt gives the finished glass a deep blue colour.
Frequently asked questions about Glass
What is Glass?
An amorphous solid made by fusing silica with soda and lime.
Is Glass a beginner, intermediate or advanced topic?
Glass is a intermediate topic in Inorganic Chemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Glass?
Study these earlier topics in Inorganic Chemistry first: Silicon Chemistry, Silicates, Silicones.
What comes after Glass?
The next topics in Inorganic Chemistry are Carbon Oxides and Carbides.
Can I practise Glass with quizzes?
Yes. The interactive lesson includes a self-check question on Glass, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Glass fits in Inorganic Chemistry
Glass is topic 28 of 113 in Inorganic Chemistry.