Barium Sulfide(BaS) Properties(25 Facts You Should Know)

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Barium sulfide naturally found as the barite mineral, is an inorganic compound. Let us look at the many properties of barium sulfide.

Barium sulfide, also called as Black Ash, is an important precursor for other barium compounds. Barium sulfide is prepared in an inert atmosphere by the calcination reaction of the elements directly. It is a short wavelength emitter and has a refractive index of 2.155.

Let us delve into the physical and chemical properties such as melting point, crystal structure, chemical classification and the reactions of this compound in detail.

BaS IUPAC Name

The IUPAC Name (International Union of Pure and Applied Chemistry) of Barium sulfide is barium sulfide sulfanylidenebarium. Barium sulfide is also named as thioxobarium.

BaS Chemical Formula

The chemical formula of Barium sulfide is BaS.

BaS CAS Number

The CAS (Chemical Abstracts Services) registry number of Barium sulfide for verification of the chemical is 21109-95-5.

BaS ChemSpider ID

The ChemSpider ID (free chemical structure database) of Barium sulfide is 5256933.

BaS Chemical Classification

  • Barium sulfide is an inorganic thermodynamically stable chemical.
  • Barium sulfide is an inorganic sulfide that shows solubility in water but insoluble in organic solvents. 
  • An aqueous solution of Barium sulfide slowly oxidizes in the presence of air, creating elemental sulfur and different sulfur anions such as sulfite, sulfate, polysulfides, and thiosulfate.

BaS Molar Mass

The molar mass of Barium sulfide is 169.4 g/mol.

BaS Color

Barium sulfide is a colorless solid compound. However, it may show impure colored variants from pale gray to yellow.

BaS Molar Density

The molar density of Barium sulfide is 0.025 mol/cm3, as it has a density of 4.25 g/cm3.

BaS Melting Point

Barium sulfide has a melting point of 1200 ⁰C or 2192 ⁰F.

BaS Boiling Point

Barium sulfide decomposes at temperatures above 2000 ⁰C.

BaS State at Room Temperature

Barium sulfide appears as a colorless to white crystalline solid at room temperature.

BaS Ionic Bond

Barium sulfide is an ionic compound wherein a barium cation Ba2+ and a sulfide anion S2- combine to make the molecule, and an ionic bond holds these two ions together. Barium ions donate their two electrons to the sulfide atom, forming an ionic bond.

Ionic bond
Ionic Bond Formation in Barium Sulfide

BaS Ionic Radius

The ionic radius of Barium cation and Sulfur anion in Barium sulfide is 135 pm and 184 pm, respectively.

BaS Electron Configuration

Electronic configuration of an atom is referred to the representation of electrons arranged in an element’s atomic shells. Let us find out the electronic configuration of Barium sulfide.

The Electronic configuration of Barium is [Xe] 6s2. The electronic configuration of Sulfur is [Ne] 3s2 3p4, whereas Sulfide ion, i.e., S2- has an electronic configuration of [Ne] 3s2 3p6.

BaS Oxidation State

In Barium sulfide, the oxidation state of Barium is +2, and Sulfur bears an oxidation state of -2.

BaS Acidity

Barium Sulfide is moderately acidic since it is water soluble and can react with acids such as H2SO4. The acidic character arises due to the electropositive behavior of barium (Ba2+) formed upon donating its two electrons to sulfur.

Is BaS Odourless

Barium sulfide emits no distinct smell; hence it is an odourless compound.

Is BaS Paramagnetic

Paramagnetism refers to molecules with a persistent magnetic moment due to the presence of unpaired electrons in its valence shells. Let us analyze the magnetism of Barium sulfide.

Barium sulfide is not a paramagnetic molecule; instead, it is diamagnetic in nature since it does not show any presence of unpaired electron(s) in its outermost orbital.

BaS Hydrates

  • Barium sulfide forms a stable monohydrate, i.e., Barium tetra-sulfide monohydrate, BaS4.H2O as a result of precipitation in an aqueous solution.
  • Barium hydrosulfide and barium hydroxide are generated as products when Barium sulfide dissolves and dissociates in water.

2BaS + 2H2O —-> Ba(SH)2 + Ba(OH)2  

BaS Crystal Structure

Barium sulfide exists in a cubic cF8 crystal-type structure with an octahedral geometry. The space group is Fm3̅m with lattice parameters being a=b=c= 0.6381 nm and α=β=ɣ= 90.00⁰.

BaS Polarity and Conductivity

  • Barium sulfide is a polar ionic molecule because of the high electronegativity difference (approximately 1.7) between the two bonded atoms.
  • Barium sulfide is a fairly good conductor of electricity as it is highly soluble in water and the presence of ions makes it applicable to conduct electricity. However, it cannot conduct electricity in its solid form.

BaS Reaction with Acid

  • Barium sulfide reacts with sulfuric acid in an acid-base reaction to form barium sulfate.

BaS (aq) + H2SO4 (aq) —-> BaSO4 (s) + H2S (aq)

  • Barium sulfide on reaction with nitric acid yields Barium nitrate, crystalline solid rhombic Sulfur, Dinitrogen trioxide gas, and water.

2BaS (s) + 6HNO3 (aq) —-> 2Ba(NO3)2 (s) + 2S (s) + N2O3 (g) + 3H2O (aq)

  • Reaction between Barium sulfide and a weak acid, acetic acid, leads to the formation of barium acetate and hydrogen sulfide.

BaS + 2CH3COOH —-> (CH3COO)2Ba + H2S

BaS Reaction with Base

Barium sulfide shows a low reactivity with bases. However, it reacts with sodium hydroxide base in a single-step reaction that leads to the production of barium hydroxide and sodium sulfide as a by-product.

BaS + 2NaOH —-> Ba(OH)2 + Na2S

BaS Reaction with Oxide

  • Barium sulfide is involved in a reaction with carbon dioxide in the presence of water to produce barium carbonate and hydrogen sulfide.

BaS + CO2 + H2O —-> BaCO3 + H2S

  • When Barium sulfide is heated with powerful oxidants such as phosphorus pentoxide, explosive oxidation might take place, for which no chemical reaction has been reported so far.

BaS Reaction with Metal

Barium sulfide, an alkaline earth metal sulfide, does not directly bond with metals and thus exhibits no known reactions.

Conclusion

Barium sulfide although hazardous, is utilized in a broad range of uses, including paint pigments, electronics, flame retardants, luminescent paints, manufacturing of pure hydrogen sulfide, hair removal creams, foams and gels. Barium sulfide aids in biomedical applications as the molecule can deviate X-rays.