Lead(II,IV) oxide

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Lead(II,IV) oxide
Red lead.jpg
Names
Preferred IUPAC name
Lead tetroxide [1]
Other names
Minium, red lead, triplumbic tetroxide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.013.851 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 215-235-6
PubChem CID
UNII
UN number 1479
  • InChI=1S/4O.3Pb Yes check.svgY
    Key: XMFOQHDPRMAJNU-UHFFFAOYSA-N Yes check.svgY
  • O1[Pb]O[Pb]11O[Pb]O1
Properties
Pb3O4
Molar mass 685.6 g·mol−1
AppearanceVivid orange crystals
Density 8.3 g/cm3
Melting point 500 °C (decomposition)
Vapor pressure 1.3 kPa (at 0 °C)
Structure
Tetragonal, tP28
P42/mbc, No. 135
Hazards
GHS labelling:
GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H272, H302, H332, H360, H373, H410
P201, P220, P273, P308+P313, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
0
0
Related compounds
Related lead oxides
Lead(II) oxide
Lead(IV) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Lead(II,IV) oxide, also called red lead or minium, is the inorganic compound with the formula Pb3O4. A bright red or orange solid, it is used as pigment, in the manufacture of batteries, and rustproof primer paints. It is an example of a mixed valence compound, being composed of both Pb(II) and Pb(IV) in the ratio of two to one. [2]

Contents

Structure

Lead(II,IV) oxide is lead(II) orthoplumbate(IV) [Pb2+]2[PbO4−4]. [3] It has a tetragonal crystal structure at room temperature, which then transforms to an orthorhombic (Pearson symbol oP28, Space group Pbam, No. 55) form at temperature 170 K (−103 °C). This phase transition only changes the symmetry of the crystal and slightly modifies the interatomic distances and angles. [4]

Preparation

Lead(II,IV) oxide is prepared by calcination of lead(II) oxide (PbO; also called litharge) in air at about 450–480 °C: [5]

6 PbO + O2 → 2 Pb3O4

The resulting material is contaminated with PbO. If a pure compound is desired, PbO can be removed by a potassium hydroxide solution:

PbO + KOH + H2O → K[Pb(OH)3]

Another method of preparation relies on annealing of lead(II) carbonate (cerussite) in air:

6 PbCO3 + O2 → 2 Pb3O4 + 6 CO2

Yet another method is oxidative annealing of white lead:

3 Pb2CO3(OH)2 + O2 → 2 Pb3O4 + 3 CO2 + 3 H2O

In solution, lead(II,IV) oxide can be prepared by reaction of potassium plumbate with lead(II) acetate, yielding yellow insoluble lead(II,IV) oxide monohydrate Pb3O4·H2O, which can be turned into the anhydrous form by gentle heating:

K2PbO3 + 2 Pb(OCOCH3)2 + H2O → Pb3O4 + 2 KOCOCH3 + 2 CH3COOH

Natural minium is uncommon, forming only in extreme oxidizing conditions of lead ore bodies. The best known natural specimens come from Broken Hill, New South Wales, Australia, where they formed as the result of a mine fire. [6]

Reactions

Red lead is virtually insoluble in water and in ethanol. However, it is soluble in hydrochloric acid present in the stomach, and is therefore toxic when ingested. It also dissolves in glacial acetic acid and a diluted mixture of nitric acid and hydrogen peroxide.

When heated to 500 °C, it decomposes to lead(II) oxide and oxygen. At 580 °C, the reaction is complete.

2 Pb3O4 → 6 PbO + O2

Nitric acid dissolves the lead(II) oxide component, leaving behind the insoluble lead(IV) oxide:

Pb3O4 + 4 HNO3 → PbO2 + 2 Pb(NO3)2 + 2 H2O

With iron oxides and with elemental iron, lead(II,IV) oxide forms insoluble iron(II) and iron(III) plumbates, which is the basis of the anticorrosive properties of lead-based paints applied to iron objects.

Use

Red lead has been used as a pigment for primer paints for iron objects. Due to its toxicity, its use is being limited. It finds limited use in some amateur pyrotechnics as a delay charge and was used in the past in the manufacture of dragon's egg pyrotechnic stars.

Red lead is used as a curing agent in some polychloroprene rubber compounds. It is used in place of magnesium oxide to provide better water resistance properties.

Red lead was used for engineer's scraping, before being supplanted by engineer's blue. Although red lead still offers more accurate markings since it doesn't flow as readily as engineer's blue under pressure.

It is also used as an adulterating agent in turmeric powder.

Physiological effects

When inhaled, lead(II,IV) oxide irritates the lungs. In case of high dose, the victim experiences a metallic taste, chest pain, and abdominal pain. When ingested, it is dissolved in the gastric acid and absorbed, leading to lead poisoning. High concentrations can be absorbed through skin as well, and it is important to follow safety precautions when working with lead-based paint.

Long-term contact with lead(II,IV) oxide may lead to accumulation of lead compounds in organisms, with development of symptoms of acute lead poisoning. Chronic poisoning displays as agitation, irritability, vision disorders, hypertension, and a grayish facial hue.

Lead(II,IV) oxide was shown to be carcinogenic for laboratory animals. Its carcinogenicity for humans was not proven.

Minium from a mine fire at Broken Hill, Australia Minium- BYU.jpg
Minium from a mine fire at Broken Hill, Australia

History

This compound's Latin name minium originates from the Minius, a river in northwest Iberia where it was first mined.

Lead(II,IV) oxide was used as a red pigment in ancient Rome, where it was prepared by calcination of white lead. In the ancient and medieval periods it was used as a pigment in the production of illuminated manuscripts, and gave its name to the minium or miniature, a style of picture painted with the colour.

Made into a paint with linseed oil, red lead was used as a durable paint to protect exterior ironwork. In 1504 the portcullis at Stirling Castle in Scotland was painted with red lead, as were cannons including Mons Meg. [7]

As a finely divided powder, it was also sprinkled on dielectric surfaces to study Lichtenberg figures.

In traditional Chinese medicine, red lead is used to treat ringworms and ulcerations, though the practice is limited due to its toxicity. Also, azarcón, a Mexican folk remedy for gastrointestinal disorders, contains up to 95% lead(II,IV) oxide. [8]

It was also used before the 18th century as medicine. [9]

See also

Related Research Articles

In chemistry, an amphoteric compound is a molecule or ion that can react both as an acid and as a base. What exactly this can mean depends on which definitions of acids and bases are being used.

<span class="mw-page-title-main">Prussian blue</span> Synthetic pigment

Prussian blue is a dark blue pigment produced by oxidation of ferrous ferrocyanide salts. It has the chemical formula FeIII
4[FeII
(CN)
6]
3. Turnbull's blue is chemically identical, but is made from different reagents, and its slightly different color stems from different impurities and particle sizes.

<span class="mw-page-title-main">Iron(III) oxide</span> Chemical compound

Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It occurs in nature as the mineral hematite, which serves as the primary source of iron for the steel industry. It is also known as red iron oxide, especially when used in pigments.

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

Lead(II) nitrate is an inorganic compound with the chemical formula Pb(NO3)2. It commonly occurs as a colourless crystal or white powder and, unlike most other lead(II) salts, is soluble in water.

<span class="mw-page-title-main">Chromate and dichromate</span> Chromium(VI) anions

Chromate salts contain the chromate anion, CrO2−
4. Dichromate salts contain the dichromate anion, Cr
2O2−
7. They are oxyanions of chromium in the +6 oxidation state and are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible.

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

Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula PbO. PbO occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern applications for PbO are mostly in lead-based industrial glass and industrial ceramics, including computer components. It is an amphoteric oxide.

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

Lead(II) chloride (PbCl2) is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead(II) chloride is one of the most important lead-based reagents. It also occurs naturally in the form of the mineral cotunnite.

<span class="mw-page-title-main">Copper(II) oxide</span> Chemical compound – an oxide of copper with formula CuO

Copper(II) oxide or cupric oxide is an inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu2O or copper(I) oxide (cuprous oxide). As a mineral, it is known as tenorite, or sometimes black copper. It is a product of copper mining and the precursor to many other copper-containing products and chemical compounds.

Comproportionation or symproportionation is a chemical reaction where two reactants containing the same element but with different oxidation numbers, form a compound having an intermediate oxidation number. It is the opposite of disproportionation.

<span class="mw-page-title-main">Tin(II) oxide</span> Chemical compound, stannous oxide (SnO)

Tin(II) oxide is a compound with the formula SnO. It is composed of tin and oxygen where tin has the oxidation state of +2. There are two forms, a stable blue-black form and a metastable red form.

In chemistry, a plumbate often refers to compounds that can be viewed as derivatives of the hypothetical PbO2−3 anion.

<span class="mw-page-title-main">Tin(IV) oxide</span> Chemical compound known as stannic oxide, cassiterite and tin ore

Tin(IV) oxide, also known as stannic oxide, is the inorganic compound with the formula SnO2. The mineral form of SnO2 is called cassiterite, and this is the main ore of tin. With many other names, this oxide of tin is an important material in tin chemistry. It is a colourless, diamagnetic, amphoteric solid.

<span class="mw-page-title-main">Lead dioxide</span> Chemical compound

Lead(IV) oxide, commonly known as lead dioxide, is an inorganic compound with the chemical formula PbO2. It is an oxide where lead is in an oxidation state of +4. It is a dark-brown solid which is insoluble in water. It exists in two crystalline forms. It has several important applications in electrochemistry, in particular as the positive plate of lead acid batteries.

Lead(II) hydroxide, Pb(OH)2, is a hydroxide of lead, with lead in oxidation state +2.

Lead oxides are a group of inorganic compounds with formulas including lead (Pb) and oxygen (O).

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

Lead(II) chromate is an inorganic compound with the chemical formula PbCrO4. It is a bright yellow solid that is very poorly soluble in water. It occurs also as the mineral crocoite. It is used as a pigment.

<span class="mw-page-title-main">Lead(IV) acetate</span> Organometallic compound (Pb(C2H3O2)4)

Lead(IV) acetate or lead tetraacetate is an metalorganic compound with chemical formula Pb(C2H3O2)4. It is a colorless solid that is soluble in nonpolar, organic solvents, indicating that it is not a salt. It is degraded by moisture and is typically stored with additional acetic acid. The compound is used in organic synthesis.

<span class="mw-page-title-main">Lead compounds</span> Type of compound

Compounds of lead exist with lead in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) compounds are typically strong oxidants or exist only in highly acidic solutions.

<span class="mw-page-title-main">Polonium dioxide</span> Chemical compound

Polonium dioxide (also known as polonium(IV) oxide) is a chemical compound with the formula PoO2. It is one of three oxides of polonium, the other two being polonium monoxide (PoO) and polonium trioxide (PoO3). It is a pale yellow crystalline solid at room temperature. Under lowered pressure (such as a vacuum), it decomposes into elemental polonium and oxygen at 500 °C. It is the most stable oxide of polonium and is an interchalcogen.

References

  1. ↑ "VOLUNTARY RISK ASSESSMENT REPORT ON LEAD AND SOME INORGANIC LEAD COMPOUNDS" . Retrieved 2012-12-25.
  2. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  3. ↑ Egon Wiberg; Nils Wiberg; Arnold Frederick Holleman (2001). Inorganic chemistry. Academic Press. p. 920. ISBN   0-12-352651-5.
  4. ↑ Gavarri, J; Weigel, Dominique; Hewat, A. W. (1978). "Oxydes de plomb. IV. Évolution structurale de l'oxyde Pb3O4 entre 240 et 5 K et mécanisme de la transition" [Lead oxides. IV. Structural evolution of the oxide Pb3O4 between 240 and 5 K and mechanism of transition]. Journal of Solid State Chemistry. 23 (3–4): 327. Bibcode:1978JSSCh..23..327G. doi:10.1016/0022-4596(78)90081-6.
  5. ↑ Carr, Dodd S. "Lead Compounds". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a15_249. ISBN   978-3527306732.
  6. ↑ Minium
  7. ↑ James Balfour Paul, Accounts of the Treasurer of Scotland, vol. 2 (Edinburgh, 1900), p. 277.
  8. ↑ Bose, A.; Vashistha, K; O'Loughlin, B. J. (1983). "Azarcón por empacho – another cause of lead toxicity". Pediatrics. 72: 108–118. doi:10.1542/peds.72.1.106. S2CID   37730169.
  9. ↑ "The London Lancet: A Journal of British and Foreign Medicine, Physiology, Surgery, Chemistry, Criticism, Literature and News". 1853.
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