Barium

Barium is a soft, silvery, alkaline earth metal with the atomic number 56, symbolized as Ba. Due to its high reactivity, barium is never found in nature as a free element. It belongs to Group 2 of the periodic table and is the fifth element in this group. Barium typically occurs in compounds such as barite (barium sulfate) and witherite (barium carbonate), often combined with sulfur, carbon, or oxygen.

1.0Introduction 

Barium (Ba) is a chemical element with atomic number 56, located in Group 2 of the periodic table. It is a soft, silvery, alkaline earth metal known for its high reactivity, and as such, it is never found in its free form in nature.

Barium's story began in 1600 when Italian alchemist Vincenzo Casciarolo discovered unusual pebbles, later identified as barite (barium sulfate, BaSO₄), that would glow when heated. Barium was first recognised as a distinct element in 1774, although it wasn't isolated in its pure form until 1808 by Sir Humphry Davy through electrolysis. It is relatively light, with a density about half that of iron. Barium readily oxidises when exposed to air and reacts vigorously with water, producing barium hydroxide and releasing hydrogen gas. It also reacts with most non-metals, often forming toxic compounds.

2.0Physical properties of barium

3.0Chemical properties of Barium

Barium is highly reactive and readily oxidises when exposed to air. It reacts vigorously with acids, water, and organic solvents like carbon tetrachloride. For example, barium reacts with hydrochloric acid (HCl) to form barium chloride (BaCl₂) and hydrogen gas (H₂):

Ba + 2HCl → BaCl₂ + H₂

Precipitation Reactions:

• Barium ions (Ba²⁺) readily precipitate from solution when combined with certain anions, forming insoluble salts. For example:
• • With carbonate ions (CO₃²⁻), barium forms barium carbonate (BaCO₃): Ba²⁺(aq) + CO₃²⁻(aq) ⇌ BaCO₃(s)
• With sulfate ions (SO₄²⁻), barium forms barium sulfate (BaSO₄).
• With chromate ions (CrO₄²⁻), barium forms barium chromate (BaCrO₄): Ba²⁺(aq)+CrO₄²⁻(aq) ⇌ BaCrO₄(s)
• With phosphate ions (PO₄³⁻), barium forms barium phosphate.

Cosmic Abundance:

• On a scale where silicon’s cosmic abundance is normalised to 10⁶ atoms, the estimated cosmic abundance of barium is relatively low at 3.7 atoms.

Oxidation State:

• In all known compounds, barium exhibits an oxidation state +2. This stable divalent state is due to the loss of two electrons from the outermost shell of barium atoms, forming Ba²⁺ ions. This characteristic makes it highly reactive and useful in various precipitation reactions to form solid compounds from solutions.

4.0Compounds of Barium

1. Barium Carbonate (BaCO₃)

Barium Carbonate (BaCO₃), also known as witherite, was discovered by William Withering in 1784. It is an inorganic white mineral with a molecular weight of 197.34 g/mol. It has a melting point of 811°C and a boiling point of 1360°C and reacts with calcium salts to produce calcium carbonate and barium sulfate. When combined with hydrochloric acid, it forms barium chloride, carbon dioxide, and water.

Uses of Barium Carbonate:

• Widely used in the ceramics industry for products like plates and mugs.
• Essential in making electrical ceramics such as capacitors and thermistors.
• Raw material for magnetic components and optical glass production.
• Used in brick manufacturing and as a flux and matting agent in various applications.

2. Barium Sulfate (BaSO₄) 

Barium Sulfate (BaSO₄) is a white, crystalline, non-toxic compound with a molar mass of 233.43 g/mol. It has a high density of 4.49 g/mL, a melting point of 1580°C, and a boiling point of 1600°C. Insoluble in water and alcohol, it dissolves in concentrated acids. Due to its radio opacity and water insolubility, it is used for various medical and industrial applications.

Uses of Barium Sulfate:

• Aids in diagnosing gastrointestinal diseases through GI imaging.
• Used in oil well drilling fluids.
• Acts as a filler in plastics to increase density.
• Employed in oil paintings to alter consistency.
• Serves as a radiopaque agent and is used in alloy manufacturing.
• Measures soil pH.

3. Barium Chloride (BaCl₂) 

Barium chloride is an ionic compound formed when barium, a Group 2 metal, donates its electrons to chlorine, a Group 17 halogen. Madam Curie obtained it in 1898 as a by-product of discovering radium.

Barium chloride is a white, hygroscopic solid with a molecular weight of 208.23 amu. It melts at 962°C, boils at 1560°C, and has a 3.856 g/cm³ density. It is highly soluble in water and methanol but insoluble in ethanol and ethyl acetate. Barium chloride is toxic, with a bitter, salty taste. Chemically, it forms a neutral aqueous solution, reacts with sulfate ions to produce barium sulfate, and reacts with oxalates and sodium hydroxide to form barium oxalate and barium hydroxide, respectively.

Uses of Barium Chloride:

• In manufacturing pigments, rodenticides, and pharmaceuticals.
• Purifies brine in caustic chlorine plants and is used in steel hardening and magnesium production.
• Acts as a flux, water softener, and boiler compound.
• Creates green flames in fireworks and is used in the leather and textile industries.
• Used as a starting material for other barium salts and in water treatment plants.
• In medicine, it stimulates the heart and muscles.

5.0Uses Of Barium 

Barium's applications are somewhat limited, but its compounds have diverse uses in various fields:

• Vacuum Tubes: Barium, as a pure metal or alloyed with aluminium, removes unwanted gases (gettering) from vacuum tubes, including TV image tubes. Its low vapour pressure and reactivity with oxygen, nitrogen, carbon dioxide, and water make it ideal for this role. Additionally, barium can partially remove noble gases by absorbing them into its crystal lattice.
• Alloy Production: Small amounts of barium are added to produce alloys, such as:
• • Steel and cast iron: Barium improves their properties.
  • Lead-tin soldering alloys: Barium enhances creep resistance.
  • Nickel alloys: Used in spark plugs.
  • Aluminum-silicon alloys (Silumin): Barium refines the alloy's structure.