An inert gas is used, so that the material does not chemically react.

Cement describes a substance, which will react chemically with water and develop into a material hard as stone.

Helium is an inert gas, so it will generally not chemically react with any material.

The other crystal form is black, and does not react chemically to anything except strong acids.

He-4 and He-3 are both surprisingly interesting substances, considering that they do not react chemically with anything.

It forms when pollutants from cars, factories and other sources react chemically with sunlight.

Salt also reacts chemically with water and foods to bring about specific results.

At this higher temperature, normal clay would react chemically with the glass.

On hot, sunny days, pollutants from vehicles, industry, and many products may chemically react with each other.

Sweat running on me suddenly, a feeling of heat as the organism reacted chemically to what the mind knew.