Bonds give materials distinctive chararistis. Strain makes a difference in how bonds form.

Dry Ice

Dry ice is a solid form of carbon dioxide. It is used as a cooling agent and for preserving food. To create dry ice two oxygen atoms are bonded with a single atom of carbon. Dry ice smokes because of the condensation of the carbon dioxide and warm air. The smoke is actually fog though.

Alloys

Alloys are mixtures composed of two or more elements of which at least one of these elements is a metal.
Sterling silver is an example of a alloy. It is composed of copper and sterling silver. This alloy is harder and more durable than regular silver. However, it is still soft enough to be made into jewelry. Another alloy is bronze. Bronze is composed of copper and tin. It is harder than copper and more easily cast. It is used to make coins.