PbO

Lead(II) oxide

Names
IUPAC name Lead(II) oxide
Other names Lead monoxide Litharge Massicot Plumbous oxide
Identifiers
CAS Number	1317-36-8 Y
ECHA InfoCard	100.013.880
PubChem CID	14827
RTECS number	OG1750000
UN number	3288
Properties
Chemical formula	PbO
Molar mass	223.20 g/mol
Appearance	red or yellow powder
Density	9.53 g/cm3
Melting point	888 °C (1,630 °F; 1,161 K)
Boiling point	1,477 °C (2,691 °F; 1,750 K)
Solubility in water	0.017 g/L
Solubility	insoluble in dilute alkalis, alcohol soluble in concentrated alkalis soluble in HCl, ammonium chloride
Magnetic susceptibility (χ)	−42.0·10−6 cm3/mol
Structure
Crystal structure	tetragonal, tP4
Space group	P4/nmm, No. 129
Hazards
Safety data sheet	ICSC 0288
EU classification (DSD)	Repr. Cat. 1/3 Harmful (Xn) Dangerous for the environment (N)
R-phrases	R61, R20/22, R33, R62, R50/53
S-phrases	S53, S45, S60, S61
NFPA 704	0 3 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LDLo (lowest published)	1400 mg/kg (dog, oral)
Related compounds
Other anions	Lead sulfide Lead selenide Lead telluride
Other cations	Carbon monoxide Silicon monoxide Tin(II) oxide
Related lead oxides	Lead(II,II,IV) oxide Lead dioxide
Related compounds	Thallium(III) oxide Bismuth(III) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula PbO. PbO occurs in two polymorphs, one litharge having a tetragonal crystal structure and the other 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.

PbO may be prepared by heating lead metal in air at approx. 600 °C. At this temperature it is also the end product of oxidation of other in air:

Thermal decomposition of lead(II) nitrate or lead carbonate also results in the PbO formation:

PbO is produced on a large scale as an intermediate product in refining raw lead ores into metallic lead. The usual lead ore is galena (lead(II) sulfide). At high temperature (1000 °C) the sulfide is converted to the oxide:

Metallic lead is obtained by reducing the PbO with carbon monoxide at around 1200 °C:.

As determined by X-ray crystallography, both polymorphs, tetragonal and orthorhombic feature a pyramidal four-coordinate Pb center. In the tetragonal form the four Pb-O bonds have the same length, but in the orthorhombic two are shorter and two longer. The pyramidal nature indicates the presence of a stereo-chemically active lone pair of electrons. When PbO occurs in tetragonal lattice structure it is called litharge; and when the PbO has orthorhombic lattice structure it is called massicot. The PbO can be changed from massicot to litharge or vice versa by controlled heating and cooling. The tetragonal form is usually red or orange color, while the orthorhombic is usually yellow or orange, but the color is not a very reliable indicator of the structure. The tetragonal and orthorhombic forms of PbO occur naturally as rare minerals.