Lithopone

Last updated
Lithopone
Names
Other names
Barium zinc sulfate sulfide, Enamel White, Pigment white 5, CI Pigment white 5, Barium zinc sulfate, Barium zinc sulfide, Lithopone B301, ZNS 28-30%, Lithopone 28-30%, LithoponeB311, Zinc sulfide, Barium sulfate Mixture, Pigment White 5 (77115), Becton White, Charlton White, Zincolith
Identifiers
ChemSpider
ECHA InfoCard 100.014.286 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 215-715-5
PubChem CID
Properties
Molar mass 330.80 g/mol
AppearanceWhite powder
Odor odorless
Density Approx. 4.36 g/mL
Melting point ZnS > 1,180°C

BaSO4 > 1,350 °C

Insoluble
Hazards
GHS labelling:
GHS-pictogram-exclam.svg
Warning
H302, H332
P261, P264, P270, P271, P301+P312, P304+P312, P304+P340, P312, P330, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
1
0
1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Lithopone, C.I. Pigment White 5, is a mixture of inorganic compounds, widely used as a white pigment powder. It is composed of a mixture of barium sulfate and zinc sulfide. These insoluble compounds blend well with organic compounds and confer opacity. It was made popular by the cheap production costs, greater coverage. Related white pigments include titanium dioxide, zinc oxide ("zinc white"), zinc sulfide, and white lead. [1]

Contents

History

Lithopone was discovered in the 1870s by DuPont. It was manufactured by Krebs Pigments and Chemical Company and other companies. [2] The material came in different "seals", which varied in the content of zinc sulfide. Gold seal and Bronze seals contain 40-50% zinc sulfide, offering more hiding power and strength. [3] Although its popularity peaked around 1920, approximately 223,352 tons were produced in 1990. It is mainly used in paints, putty, and in plastics. [1]

Stability and darkening

Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.

Production

Lithopone is produced by coprecipitation of barium sulfate and zinc sulfide. Most commonly coprecipitation is effected by combining equimolar amounts of zinc sulfate and barium sulfide:

BaS + ZnSO4→ ZnS · BaSO4

This route affords a product that is 29.4 wt % ZnS and 70.6 wt % BaSO4. Variations exist, for example, more ZnS-rich materials are produced when zinc chloride is added to the mixture of zinc sulfate and barium sulfide. [1]

Barium sulfide is produced by carbothermic reduction of barium sulfate. Zinc sulfate is obtained from a variety of zinc products, often waste, by treatment with sulfuric acid.

Safety

Lithopone is rather nontoxic, due to the insolubility of its components. It has been used in medicine as a radiocontrast agent. Lithopone is allowed to be in contact with foodstuffs in the US and Europe. [1]

See also

Related Research Articles

<span class="mw-page-title-main">Barium</span> Chemical element, symbol Ba and atomic number 56

Barium is a chemical element; it has symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.

Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. Sulfide also refers to large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH) are the conjugate acids of sulfide.

<span class="mw-page-title-main">Lead(II) sulfate</span> Chemical compound

Lead(II) sulfate (PbSO4) is a white solid, which appears white in microcrystalline form. It is also known as fast white, milk white, sulfuric acid lead salt or anglesite.

<span class="mw-page-title-main">Zinc sulfate</span> Chemical compound

Zinc sulfate describes a family of inorganic compounds with the formula ZnSO4(H2O)x. All are colorless solids. The most common form includes water of crystallization as the heptahydrate, with the formula ZnSO4·7H2O. As early as the 16th century it was prepared on the large scale, and was historically known as "white vitriol" (the name was used, for example, in 1620s by the collective writing under the pseudonym of Basil Valentine). Zinc sulfate and its hydrates are colourless solids.

<span class="mw-page-title-main">Barium hydroxide</span> Chemical compound

Barium hydroxide is a chemical compound with the chemical formula Ba(OH)2. The monohydrate (x = 1), known as baryta or baryta-water, is one of the principal compounds of barium. This white granular monohydrate is the usual commercial form.

<span class="mw-page-title-main">Zinc sulfide</span> Inorganic compound

Zinc sulfide is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various impurities, the pure material is white, and it is widely used as a pigment. In its dense synthetic form, zinc sulfide can be transparent, and it is used as a window for visible optics and infrared optics.

<span class="mw-page-title-main">Barium sulfate</span> Inorganic chemical compound

Barium sulfate (or sulphate) is the inorganic compound with the chemical formula BaSO4. It is a white crystalline solid that is odorless and insoluble in water. It occurs in nature as the mineral barite, which is the main commercial source of barium and materials prepared from it. Its opaque white appearance and its high density are exploited in its main applications.

<span class="mw-page-title-main">Barium chloride</span> Chemical compound

Barium chloride is an inorganic compound with the formula BaCl2. It is one of the most common water-soluble salts of barium. Like most other water-soluble barium salts, it is a white powder, highly toxic, and imparts a yellow-green coloration to a flame. It is also hygroscopic, converting to the dihydrate BaCl2·2H2O, which are colourless crystals with a bitter salty taste. It has limited use in the laboratory and industry.

<span class="mw-page-title-main">Barium nitrate</span> Chemical compound

Barium nitrate is the inorganic compound with the chemical formula Ba(NO3)2. It, like most barium salts, is colorless, toxic, and water-soluble. It burns with a green flame and is an oxidizer; the compound is commonly used in pyrotechnics.

Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find the elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution, therefore materials in other forms may need to be brought to this state before using standard methods. The solution is then treated with various reagents to test for reactions characteristic of certain ions, which may cause color change, precipitation and other visible changes.

In chemistry, water(s) of crystallization or water(s) of hydration are water molecules that are present inside crystals. Water is often incorporated in the formation of crystals from aqueous solutions. In some contexts, water of crystallization is the total mass of water in a substance at a given temperature and is mostly present in a definite (stoichiometric) ratio. Classically, "water of crystallization" refers to water that is found in the crystalline framework of a metal complex or a salt, which is not directly bonded to the metal cation.

<span class="mw-page-title-main">Zinc selenide</span> Chemical compound

Zinc selenide is the inorganic compound with the formula ZnSe. It is a lemon-yellow solid although most samples have a duller color due to the effects of oxidation. It is an intrinsic semiconductor with a band gap of about 2.70 eV at 25 °C (77 °F), equivalent to a wavelength of 459 nm. ZnSe occurs as the rare mineral stilleite, named after Hans Stille.

<span class="mw-page-title-main">Zinc pyrophosphate</span> Chemical compound

Zinc pyrophosphate (Zn2P2O7) is an ionic inorganic chemical compound composed of Zn2+ cations and pyrophosphate anions.

<span class="mw-page-title-main">Barium sulfide</span> Chemical compound

Barium sulfide is the inorganic compound with the formula BaS. BaS is the barium compound produced on the largest scale. It is an important precursor to other barium compounds including BaCO3 and the pigment lithopone, ZnS/BaSO4. Like other chalcogenides of the alkaline earth metals, BaS is a short wavelength emitter for electronic displays. It is colorless, although like many sulfides, it is commonly obtained in impure colored forms.

<span class="mw-page-title-main">Barium peroxide</span> Chemical compound

Barium peroxide is an inorganic compound with the formula BaO2. This white solid is one of the most common inorganic peroxides, and it was the first peroxide compound discovered. Being an oxidizer and giving a vivid green colour upon ignition, it finds some use in fireworks; historically, it was also used as a precursor for hydrogen peroxide.

<span class="mw-page-title-main">Barium bromide</span> Chemical compound

Barium bromide is the chemical compound with the formula BaBr2. It is ionic and hygroscopic in nature.

<span class="mw-page-title-main">Sachtleben Chemie</span>

Sachtleben Chemie is a chemicals producer, with its primary focus on the production of white pigments, fillers and extenders. The company employs some 2,200 persons and achieves annual sales of around 820 million euros (2012). Sachtleben has been a member of the multinational Venator group since 2017. The company's corporate history reaches back over 130 years. Sachtleben produces particles using titanium dioxide, zinc sulfide and barium sulfate as the chemical basis, and markets these products worldwide. The principal applications for Sachtleben products include man-made fibers, paints and other coatings, plastics, and paper. Sachtleben also supplies special particles to the foodstuffs, pharmaceuticals and cosmetics industries, and has interests in the fields of chromatography, nanotechnology, catalysis, and the production of building materials. The company leads the world in special titanium dioxide grades for printing inks and for the cosmetics, pharmaceuticals and food industries. The production facilities at all three locations apply the sophisticated sulfate-route process.

References

  1. 1 2 3 4 Völz, Hans G. et al. "Pigments, Inorganic" in Ullmann's Encyclopedia of Industrial Chemistry, 2006 Wiley-VCH, Weinheim. doi : 10.1002/14356007.a20_243.pub2.
  2. "Krebs Pigment & Chemical Company". DuPont. Archived from the original on 2011-05-11. Retrieved 2011-10-24. Founded in 1902 by Henrick J. Krebs, Krebs Pigments and Chemical Company produced lithopone, a widely used white paint pigment also manufactured by DuPont. But Krebs' company had another asset of special interest to DuPont. ...
  3. Booge, J. E. (1929). "Lithopone Composition and Process of Making Same".{{cite journal}}: Cite journal requires |journal= (help)

Historical references