Barium sulphate formula and chemical name
The formula of barium sulphate (barium sulfate) is BaSO4: one barium ion, Ba2+, and one sulphate ion, SO42−. So when you see BaSO4, the chemical name is barium sulphate. It is a white, odourless inorganic solid that occurs in nature as the mineral barite (also called barytes) and is also made synthetically, when it is usually sold as blanc fixe.
| Item | Value |
|---|---|
| Formula | BaSO4 |
| Molar mass | 233.39 g/mol |
| CAS number | 7727-43-7 |
| Other names | Barium sulfate, blanc fixe, artificial barite; natural form: barite, barytes |
| HS code (6-digit) | 2511.10 natural barytes; 2833.27 precipitated barium sulphate |
The molar mass adds up from barium 137.33, sulphur 32.06 and four oxygens at 16.00 each: 137.33 + 32.06 + 64.00 = 233.39 g/mol, the value in the NIST Chemistry WebBook.
Barite, barytes and blanc fixe
Buyers meet several names for the same compound. Barite and barytes are the natural mineral, mined and ground. Blanc fixe is the name used for artificial, precipitated barium sulphate; the ILO International Chemical Safety Card lists “blanc fixe” and “artificial barite” as synonyms. Customs treats them differently too: natural barytes is classified under HS 2511.10, while precipitated barium sulphate falls under 2833.27 with the other sulphates of barium.
When you enquire, say which form you need and what it is for, because the two are sold into different applications and specified in different ways.
Physical properties and colour
| Property | Value | Source |
|---|---|---|
| Appearance and colour | White or yellowish odourless powder or small crystals | NOAA CAMEO; ICSC 0827 |
| Density | 4.5 g/cm³ (specific gravity 4.25 to 4.5) | ICSC 0827; NOAA CAMEO |
| Solubility in water | Practically insoluble (0.0002% at 64 °F); also insoluble in dilute acids and alcohol | NOAA CAMEO |
| Thermal behaviour | Decomposes at about 1,600 °C | ICSC 0827 |
| Reactivity | No rapid reaction with air or water; not combustible | NOAA CAMEO; ICSC 0827 |
Its whiteness, high density, chemical inertness and insolubility are what make it useful. When heated to decomposition it gives off toxic sulphur oxides.
Where barium sulphate is used
According to the US Geological Survey, more than 90% of the barite sold in the United States is typically used as a weighting agent in the fluids used to drill oil and natural gas wells. Barite is also used as a filler, extender or weighting agent in paints, plastics and rubber, in automobile brake and clutch pads and paint primers, and as aggregate in high-density concrete for radiation shielding around X-ray units.
NOAA CAMEO also lists paper coatings, linoleum and textiles, and its use as a radio-opaque aid in medical diagnostics (the “barium meal”), which relies on the same insolubility.
Is barium sulphate hazardous?
NOAA CAMEO describes barium sulphate as non-combustible and non-toxic; unlike soluble barium salts, it is practically insoluble. The dust is still an irritant: exposure can irritate the eyes, nose and upper respiratory tract, and long-term inhalation of the dust can cause baritosis, a benign pneumoconiosis. Control dust, use eye and respiratory protection where dust is generated, and follow the SDS for the grade you buy.
Questions to ask a supplier
- Is the material natural barite or precipitated blanc fixe?
- Which grade is it, and what does the Certificate of Analysis report for the batch?
- What particle size and whiteness figures are given on the technical data sheet?
- Can you share the current SDS, including the transport classification for the shipment?
- What packaging, Incoterms and destination ports are available?
Enquire with Scapex Exports
Scapex Exports is an exporter and supplier of industrial and fine chemicals from India. Barium sulphate products in our catalogue include barium sulphate precipitated (blanc fixe), barytes (barium sulfate) and barium sulphate filler. Each product page links to its COA and MSDS.
Send the form you need, the grade, quantity, packing and destination port, and we will reply with a quotation.
Frequently asked questions
What is the formula of barium sulphate?
BaSO4. It is made of one barium ion (Ba2+) and one sulphate ion (SO4 2−), with a molar mass of 233.39 g/mol and CAS number 7727-43-7.
What colour is barium sulphate?
White. NOAA CAMEO describes it as a white or yellowish odourless powder or small crystals.
Is blanc fixe the same as barium sulphate?
Yes. Blanc fixe is a name for artificial (precipitated) barium sulphate. Barite or barytes is the natural mineral form.
Does barium sulphate dissolve in water?
It is practically insoluble. NOAA CAMEO gives a water solubility of 0.0002% at 64 °F.
What is barium sulphate mainly used for?
Mostly as a weighting agent in oil and gas drilling fluids, and as a filler or extender in paints, plastics and rubber. It is also used in brake pads, paper coatings, radiation-shielding concrete and as an X-ray contrast agent.
Sources: NIST Chemistry WebBook (CAS 7727-43-7); NOAA CAMEO Chemicals, barium sulfate; ILO/WHO International Chemical Safety Card 0827; US Geological Survey, Mineral Commodity Summaries 2025: Barite.