Massicot

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Massicot
Massicot-177335.jpg
Massicot from the Monte Cristo mine, Goodsprings District, Clark County, Nevada (size: 5.0 x 4.0 x 4.0 cm)
General
Category Oxide mineral
Formula
(repeating unit)
PbO
IMA symbol Msi [1]
Strunz classification 4.AC.25
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space group Pbcm
Unit cell a = 5.4903 Å, b = 5.892 Å,
c = 4.752 Å; Z = 4
Identification
ColorYellow may have a red tint
Crystal habit Scaly as incrustations, massive
Cleavage Distinct on {100} and {010}
Fracture Flexible
Mohs scale hardness2
Luster Greasy to dull
Streak Yellow
Diaphaneity Translucent
Specific gravity 9.642 calculated
Optical propertiesBiaxial (+)
Refractive index nα = 2.510 nβ = 2.610 nγ = 2.710
Birefringence δ = 0.200
Pleochroism Y = light sulfur-yellow; Z = deep yellow
2V angle Measured: 90°, calculated: 86°
Dispersion Strong
References [2] [3] [4] [5]

Massicot is lead (II) oxide mineral with an orthorhombic lattice structure. Lead(II) oxide (formula: PbO) can occur in one of two lattice formats, orthorhombic and tetragonal. The red tetragonal form is called litharge. PbO can be changed from massicot to litharge (or vice versa) by controlled heating and cooling. At room temperature massicot forms soft (Mohs hardness of 2) yellow to reddish-yellow, earthy, scaley masses which are very dense, with a specific gravity of 9.64. Massicot can be found as a natural mineral, though it is only found in minor quantities. In bygone centuries it was mined. Nowadays massicot arises during industrial processing of lead and lead oxides, [6] especially in the glass industry, which is the biggest user of PbO.

The definition of massicot as orthorhombic PbO dates from the 1840s, [5] but the substance massicot and the name massicot has been in use since the late medieval era. [7] There is some evidence that the ancient Romans used the substance. [8]

It may occur as an oxidation product of other lead-bearing minerals such as galena, bournonite, boulangerite, either naturally or in industrial processing. When massicot is found in a natural environment, some other minerals that may be found with it may include cerussite, litharge, minium, wulfenite, valentinite and limonite. [3]

Related Research Articles

<span class="mw-page-title-main">Wulfenite</span> Molybdate mineral

Wulfenite is a lead molybdate mineral with the formula PbMoO4. It can be most often found as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called "yellow lead ore".

<span class="mw-page-title-main">Anglesite</span> Lead sulfate mineral

Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and celestine. It contains 74% of lead by mass and therefore has a high specific gravity of 6.3. Anglesite's color is white or gray with pale yellow streaks. It may be dark gray if impure.

<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,IV) oxide</span> Chemical compound

Lead(II,IV) oxide, also called red lead or minium, is the inorganic compound with the formula . 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.

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

Litharge (from Greek lithargyros, lithos (stone) + argyros (silver) λιθάργυρος) is one of the natural mineral forms of lead(II) oxide, PbO. Litharge is a secondary mineral which forms from the oxidation of galena ores. It forms as coatings and encrustations with internal tetragonal crystal structure. It is dimorphous with the yellow orthorhombic form massicot. It forms soft (Mohs hardness of 2), red, greasy-appearing crusts with a very high specific gravity of 9.14–9.35. PbO may be prepared by heating lead metal in air at approximately 600 °C (lead melts at only 300 °C). At this temperature it is also the end product of heating of other lead oxides in air. This is often done with a set of bellows pumping air over molten lead and causing the oxidized product to slip or fall off the top into a receptacle, where it quickly solidifies in minute scales.

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

Lead(IV) oxide is the inorganic compound with the 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 oxides are a group of inorganic compounds with formulas including lead (Pb) and oxygen (O).

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

Iron(III) oxide-hydroxide or ferric oxyhydroxide is the chemical compound of iron, oxygen, and hydrogen with formula FeO(OH).

Changbaiite (PbNb2O6) is a member of the oxide mineral class in which the mineral contains oxygen which is grouped along with one or two metal ion. Changbaiite is classified as a multiple Oxide XY2O6 and it generally has an ionic bond. Furthermore, it is also orthorhombic at a temperature of 25 °C and it changes to orthorhombic-tetragonal at 570 °C.

<span class="mw-page-title-main">Gonnardite</span> Zeolite mineral

Gonnardite is a comparatively rare, fibrous zeolite, natrolite subgroup. Older papers claim that a complete solid solution exists between tetranatrolite and gonnardite, but tetranatrolite was discredited as a separate species in 1999. A series, based on the disorder of the silicon-aluminum in the framework, appears to exist between Na-rich gonnardite and natrolite, Na2(Si3Al2)O10·2H2O.

Scrutinyite is a rare oxide mineral and is the alpha crystalline form of lead dioxide (α-PbO2), plattnerite being the other, beta form. The mineral was first reported in 1988 and its name reflects the scrutiny and efforts required to identify it from a very limited amount of available sample material.

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

Plattnerite is an oxide mineral and is the beta crystalline form of lead dioxide (β-PbO2), scrutinyite being the other, alpha form. It was first reported in 1845 and named after German mineralogist Karl Friedrich Plattner. Plattnerite forms bundles of dark needle-like crystals on various minerals; the crystals are hard and brittle and have tetragonal symmetry.

<span class="mw-page-title-main">Minium (mineral)</span>

Minium is the naturally occurring form of lead tetroxide, Pb2+2Pb4+O4 also known as red lead. Minium is a light-to-vivid red and may have brown-to-yellow tints. It typically occurs in scaly-to-earthy masses. It crystallizes in the tetragonal crystal system.

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

Laurionite is a lead halide mineral. It forms colorless to white crystals in the orthorhombic crystal system and is dimorphous with paralaurionite, both members of the matlockite group.

<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">Khinite</span>

Khinite is a rare tellurate mineral with the formula Pb2+Cu2+3TeO6(OH)2 It crystallizes in the orthorhombic system and has a bottle-green colour. It is often found as dipyramidal, curved or corroded crystals no more than 0.15 mm in size. The tetragonal dimorph of khinite is called parakhinite.

Scotlandite is a sulfite mineral first discovered in a mine at Leadhills in South Lanarkshire, Scotland, an area known to mineralogists and geologists for its wide range of different mineral species found in the veins that lie deep in the mine shafts. This specific mineral is found in the Susanna vein of Leadhills, where the crystals are formed as chisel-shaped or bladed. Scotlandite was actually the first naturally occurring sulfite, which has the ideal chemical formula of PbSO3. The mineral has been approved by the Commission on New Minerals and Mineral Names, IMA, to be named scotlandite for Scotland.

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

Ramsdellite (Mn4+O2) is an orthorhombic manganese dioxide mineral. It is relatively uncommon, and is usually found in deposits containing other manganese oxide crystals.

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. Mineralienatlas
  3. 1 2 Mineral data publishing - PDF
  4. Webmineral data
  5. 1 2 Mindat with location data
  6. A simple example is given in A Text Book of Inorganic Chemistry, by Anil Kumar De, year 2007, page 383. A more complex example is in The Chemistry of Metal Alkoxides, published by Kluwer Academic Publishers, year 2002, section 9.4 on lead alkoxides, page 115.
  7. Some comments about the evolution of the definition of the word massicot over the past few centuries is in Lead Manufacturing in Britain: A History, by David John Rowe, year 1983, page 16. The word is in Italian and French in the late medieval era meaning naturally occurring massicot and in some records more vaguely a lead-based ceramics glaze that may or may not have been massicot.
  8. Archaeomineralogy, by George Robert Rapp, year 2002, page 173, says three lead oxides were known to the ancient Romans: minium, litharge, and massicot.