Britannica
Sources used in this answer
How do sodium and calcium ions affect the density of silica glass?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
industrial glass
Examining a superhydrophobic glass surface that resists fog and glare and is self-cleaning.
In silica glass, the addition of sodium and calcium ions causes the density of the material to increase steadily.1
In its pure form, silica glass possesses a random atomic structure with relatively large interstitial spaces, or "holes," between atoms, which results in a lower density compared to its crystalline counterparts. When sodium and calcium are introduced as network-modifying ions, they occupy these interstitial spaces within the glass structure. As these ions fill the available free volume, the overall density of the glass increases. Consequently, commercial soda-lime-silica glasses exhibit a higher density than pure vitreous silica.12