Strontium

Strontium (Sr) is a chemical element with an atomic number of 38 and an atomic mass of 87.62 g/mol. It belongs to the alkaline earth metals group and is known for its high reactivity due to its electronic configuration. Strontium is a silver-white metal that forms a dark oxide layer when exposed to air. It shares many physical and chemical properties with its neighbouring elements on the periodic table, such as calcium and barium. Strontium was discovered in 1790 by Adair Crawford and William Cruikshank.

1.0Introduction

Strontium (Sr) is an alkaline earth metal with a silvery-white appearance, soft enough to be cut with a knife. It naturally occurs as the mineral strontianite. Strontium has a variety of applications, including in the production of light bulbs and fireworks, where it contributes to vibrant red colours. Additionally, strontium is used to manufacture strong, durable glass and other materials that require high resilience.

2.0Occurrence in Nature

Strontium is relatively abundant in the Earth's crust, ranking about 15th in occurrence, similar to fluorine and barium. The primary strontium minerals are celestine (strontium sulfate, SrSO₄) and strontianite (strontium carbonate, SrCO₃). Major sources of strontium include Mexico, Spain, Turkey, and Iran, with smaller deposits in California and Texas.

Strontium naturally occurs in four isotopes: strontium-84, strontium-86, strontium-87, and strontium-88. Isotopes are variants of an element with the same number of protons but differ in their mass. Due to the number of neutrons. Physical Properties of Strontium 

3.0Chemical Reactions of Strontium

1. Reaction with Water: Strontium reacts slowly with water to produce strontium hydroxide and hydrogen gas. The metal sinks in water and hydrogen bubbles appear on its surface. This reaction occurs faster than that of calcium but slower than that of barium.

Sr (s)+2H₂O (l)→Sr(OH)₂ (aq) + H₂ (g)

2. Reaction with Air: When ignited in the air, strontium produces a mixture of strontium oxide and nitride. The surface of the metal is covered with a thin oxide layer, providing some protection against further oxidation, though less effective than in magnesium.

• Formation of Strontium Oxide: 2Sr (s)+O₂ (g)→2SrO (s) 
• Formation of Strontium Nitride: 3Sr (s)+N₂ (g)→Sr₃N₂ (s)

3. Reaction with Halogens: Strontium is highly reactive with halogens, forming dihalides upon reaction.

• With Chlorine: Sr (s)+Cl₂ (g)→SrCl₂ (s)
• With Bromine: This reaction occurs at about 400°C.

Sr (s)+Br2 (g)→SrBr₂ (s)

• With Iodine: This reaction takes place at dull red heat.

Sr (s)+I2 (g)→SrI2 (s)

4. Reaction with Acids: Strontium readily dissolves in dilute or concentrated hydrochloric acid, producing strontium ions and hydrogen gas.

• Sr (s)+2HCl (aq)→Sr₂+ (aq)+2Cl⁻ (aq)+H₂ (g)

4.0Uses of Strontium

Strontium has a variety of applications across different industries:

• Sugar Industry: Strontium hydroxide processes raw sugar and removes molasses from sugar beets.
• Glass for Cathode Ray Tubes (CRTs): Glass was once commonly used in CRT displays to absorb X-rays, though these tubes are now less common.
• Pyrotechnics: Strontium produces bright red colours in fireworks, flares, and tracer bullets.
• Medical Science: Certain strontium compounds may help prevent or treat bone loss, and radioactive isotopes are used in cancer treatment.
• Vacuum Space: As a getter, strontium removes unwanted gases in vacuum systems.
• Refining: It helps remove lead impurities in zinc refining.
• Alloys: Strontium improves the machinability and creep resistance of aluminium and magnesium alloys in engine parts.
• Paints and Plastics: Strontium aluminate is used in glow-in-the-dark paints, toys, and plastics, while strontium pigments are used in ceramics and paints.