What Is Barium Sulfide?
Barium sulfide is a white crystalline powder with a sulfur odor.
It is an inorganic compound composed of sulfur and barium, with the chemical formula BaS, a molecular weight of 169.39 and CAS No. 21109-95-5. It is a sodium chloride-type cubic crystal with an octahedral structure with barium and sulfur at its center.
Barium sulfide was first prepared by the Italian alchemist Vincenzo Casciarolo (1571-1624) via thermochemical reduction of barium sulfate (BaSO4).
Uses of Barium Sulfide
Barium sulfide is used to vulcanize rubber and as a reagent for generating hydrogen sulfide. It is also used in the production of a white pigment called lithopone when mixed with zinc sulfide. Barium sulfide can also be used as one of the sulfides used in a process called coloring sulfide to color the surface of copper and its alloys black.
Polysulfides of barium sulfide include yellow crystalline barium trisulfide (BaS3) and pale red orthorhombic columnar barium tetrasulfide. These mixtures are called barium sulfide flowers and are used as insecticides and leather depilatories.
They are also toxic and can cause acute poisoning and irritation, and care must be taken because hydrogen sulfide gas is generated when they come into contact with acids. Protective equipment such as protective glasses, protective gloves, protective clothing, and dust masks are expected to be used.
Properties of Barium Sulfide
1. Physical Properties
Barium sulfide has a very high melting point of 1,200°C, a density of 4.3 g/cm3, and a solubility in water of 72.8 g/L. Oxidized in air, it takes on a yellowish color and absorbs moisture and carbon dioxide, producing toxic hydrogen sulfide. In water, it gradually hydrolyzes to produce barium hydrogen sulfide and barium hydroxide, which can be treated with sodium carbonate or carbon dioxide to obtain white solid barium carbonate, the raw material for many commercial barium compounds.
2. Other Characteristics
Barium sulfide, also known as Bologna stone or lapis bologniensis because of its phosphorescence, has been experimented with by various alchemists and chemists. Like other chalcogenides of alkaline earth metals, barium sulfide is also an emitter for short wavelengths in electronic displays.
Other Information on Barium Sulfide
1. Barium Sulfide Manufacturing Process
Barium sulfide is produced by the thermochemical reduction of barium sulfate with coke (BaSO4+2C→BaS+2CO2) instead of fluorite as used in the ancient practice. This type of conversion is called carbon thermal reduction. It can also be obtained by passing a gas mixture of equal parts hydrogen sulfide and hydrogen through barium carbonate heated to about 1,000°C.
2. Handling and Storage Precautions
Precautions for handling and storage are as follows:
- Keep the container tightly closed and store in a cool, dark place.
- Keep away from heat and ignition sources.
- Store in containers with corrosion-resistant or corrosion-resistant linings.
- Use only outdoors or in well-ventilated areas.
- Avoid dispersal of dust.
- Avoid contact with acids, oxidizers, phosphates, lead, potassium chlorate, and potassium nitrate.
- Wear protective clothing, protective gloves, protective glasses, and protective masks when using.
- Wash hands thoroughly after handling.
- In case of skin contact, remove all contaminated clothing, rinse skin with running water or shower, and call a physician immediately.
- In case of eye contact, rinse cautiously with plenty of water and seek immediate medical attention from an ophthalmologist.