Barium sulfide

Not to be confused with Barium sulfate.

Barium sulfide is the inorganic compound with the formula BaS. BaS is the barium compound produced on the largest scale.^[3] It is an important precursor to other barium compounds including barium carbonate and the pigment lithopone, ZnS/BaSO₄.^[4] Like other chalcogenides of the alkaline earth metals, BaS is a short wavelength emitter for electronic displays.^[5] It is colorless, although like many sulfides, it is commonly obtained in impure colored forms.

Barium sulfide

Identifiers
CAS Number	21109-95-5 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:32590 Y
ChemSpider	5256933 Y
ECHA InfoCard	100.040.180
EC Number	244-214-4
Gmelin Reference	13627
PubChem CID	6857597
UNII	TV3U2GEW4H
CompTox Dashboard (EPA)	DTXSID30892157
InChI InChI=1S/Ba.S/q+2;-2 Y Key: CJDPJFRMHVXWPT-UHFFFAOYSA-N Y InChI=1/Ba.S/q+2;-2 Key: CJDPJFRMHVXWPT-UHFFFAOYAO
SMILES [Ba+2].[S-2]
Properties
Chemical formula	BaS
Molar mass	169.39 g/mol
Appearance	white solid
Density	4.25 g/cm3 [1]
Melting point	2,235[2] °C (4,055 °F; 2,508 K)
Boiling point	decomposes
Solubility in water	2.88 g/100 mL (0 °C) 7.68 g/100 mL (20 °C) 60.3 g/100 mL (100 °C) (reacts)
Solubility	insoluble in alcohol
Refractive index (nD)	2.155
Structure
Crystal structure	Halite (cubic), cF8
Space group	Fm3m, No. 225
Coordination geometry	Octahedral (Ba2+); octahedral (S2−)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335, H400
Precautionary statements	P261, P264, P271, P273, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	2 3 2
Lethal dose or concentration (LD, LC):
LD50 (median dose)	226 mg/kg humans
Related compounds
Other anions	Barium oxide Barium selenide Barium telluride Barium polonide
Other cations	Beryllium sulfide Magnesium sulfide Calcium sulfide Strontium sulfide Radium sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Discovery

BaS was prepared by the Italian alchemist Vincenzo Cascariolo (also known as Vincentius or Vincentinus Casciarolus or Casciorolus, 1571–1624) via the thermo-chemical reduction of BaSO₄ (available as the mineral barite).^[6] It is currently manufactured by an improved version of Cascariolo's process using coke in place of flour and charcoal. This kind of conversion is called a carbothermic reaction:

BaSO₄ + 2C → BaS + 2CO₂

and also:

BaSO₄ + 4C → BaS + 4CO

The basic method remains in use today. BaS dissolves in water. These aqueous solutions, when treated with sodium carbonate or carbon dioxide, give a white solid of barium carbonate, a source material for many commercial barium compounds.^[7]

According to Harvey (1957),^[8] in 1603, Vincenzo Cascariolo used barite, found at the bottom of Mount Paterno near Bologna, in one of his non-fruitful attempts to produce gold. After grinding and heating the mineral with charcoal under reducing conditions, he obtained a persistent luminescent material that soon came to be known as Lapis Boloniensis, or Bolognian stone.^[9][10] The phosphorescence of the material obtained by Casciarolo made it a curiosity.^[11][12][13]

Preparation

A modern procedure proceeds from barium carbonate:^[14]

BaCO₃ + H₂S → BaS + H₂O + CO₂

BaS crystallizes with the NaCl structure, featuring octahedral Ba²⁺ and S²⁻ centres.

The observed melting point of barium sulfide is highly sensitive to impurities.^[2]

Safety

BaS is quite poisonous, as are related sulfides, such as CaS, which evolve toxic hydrogen sulfide upon contact with water. Barium itself is also toxic.