Strontium oxide
Strontium oxide, strontia or SrO, is formed when strontium metal reacts with oxygen. Burning strontium in air results in a mixture of strontium oxide and strontium nitride. It also forms from the decomposition of strontium carbonate SrCO3. It is a strongly basic oxide.
Contents
Properties
Chemical
SrO reacts with water, releasing heat and producing strontium hydroxide. In open air, it reacts with water vapor and carbon dioxide, slowly converting to strontium carbonate over time.
It will react with many acids to form strontium salts and water.
- SrO + 2 HNO3 → Sr(NO3)2 + H2O
Physical
SrO is a white solid, usually in powder form. Strontium oxide will react in contact with water. It is slightly soluble in ethanol, but insoluble in acetone and ether. It has a very high melting and boiling point (2,531 °C and 3,200 °C respectively).
Availability
Strontium oxide can be purchased from chemical suppliers, although it's easier to find strontium carbonate and hydroxide than the simple oxide, as they're less reactive.
Preparation
Strontium oxide can be prepared by heating strontium hydroxide or strontium carbonate at temperatures above 710°C, where they decompose to to release water and carbon dioxide.
Projects
- Make strontium metal (reducing with aluminium in inert atmosphere or vacuum)
- Make strontium salts
- Red colored fireworks
Handling
Safety
Strontium oxide is extremely corrosive to the human tissue as it reacts vigorously with the water from them, and releases heat which causes severe burns. Gloves must be worn at all times while handling SrO.
Strontium ions, being similar to the calcium ones, pose little danger to health when consumed. In fact, many studies on both animals and humans have shown that strontium supplements can increase the density and strength of bones. However it is advised to avoid consuming lab-grade strontium compounds, as they are unfit for consumption.
Storage
Contact with damp air must be kept to a minimal to prevent it from reacting with water and oxides of carbon and nitrogen and other reactive gases.
Disposal
Strontium oxide can be neutralized with water or a cheap acid. Since most of strontium compounds are similar to calcium compounds, it can be dumped without any special precautions. However, as strontium is rarer than calcium, it's best to try to recycle the compound when possible.
