Reed Relays and
Electronics India Limited
Manufacturer of Reed Switches, Reed Sensors and Reed-based products
Reed Relays and Electronics India Limited Incorporated in 1971


Lead is a chemical element with symbol Pb (Plumbum in Latin) and atomic number 82. Lead is a soft and malleable metal, which is regarded as a heavy metal and when ingested, is poisonous. This metal is banned by the RoHS directive.

Merriam-Webster Online Dictionary
lead (verb)
transitive verb
a) to guide on a way especially by going in advance
b) to direct on a course or in a direction
c) to serve as a channel for - a pipe leads water to the house
to go through - live lead a quiet life
a) (1) to direct the operations, activity, or performance of - lead an orchestra
(2) to have charge of - lead a campaign
(3) to ask (a witness) a question in a way that suggests what the answer should be to ask (a witness) a question - leading
b) (1) to go at the head of - lead a parade
(2) to be first in or among - lead the league
(3) to have a over - margin led his opponent
to bring to some conclusion or condition - led to believe otherwise
to begin play with - lead trumps
a) to aim in front of (a moving object) - lead a duck
intransitive verb
b) to pass a ball or puck just in front of (a moving teammate)
a) to guide someone or something along a way
b) to lie, run, or open in a specified place or direction - path leads uphill
c) to guide a dance partner through the steps of a dance
a) to be first
b) (1) - begin open
(2) to play the first card of a , round, or game - trick
to tend toward or have a result - study leading to a degree
to direct the first of a series of blows at an opponent in boxing guide
lead (noun)
a) (1) - leadership
(2) - example precedent
b) (1) position at the front - vanguard
(2) - initiative
(3) the act or privilege of playing first in a card game , also the card or suit played first
c) a or measure of advantage or superiority or position in advance - margin
one that as - leads
a) - lode
b) a channel of water especially through a field of ice
c) - indication clue
d) a role in a dramatic production - principal , also one who plays such a role
e) - leash
f) (1) an introductory section of a news story
(2) a news story of chief importance
an insulated electrical connected to an electrical device - conductor
the course of a rope from end to end
the amount of axial advance of a point accompanying a complete turn of a thread (as of a screw or worm)
a position taken by a base runner off a base toward the next
the first punch of a series or an exchange of punches in boxing
lead (adjective)
acting or serving as a lead or - (see lead) leader a lead article
lead (noun)
a bluish-white soft malleable plastic but inelastic heavy metallic element found mostly in combination and used especially in pipes, cable sheaths, batteries, solder, and shields against radioactivity - ductile see element table
a) a for sounding at sea - plummet
b) British a usually flat lead roof
c) lead framing for panes in windows
d) a thin strip of metal used to separate lines of in printing - type
a) a thin stick of marking substance (as graphite) in or for a pencil
b) - white lead
- bullets projectiles
- tetraethyl lead
lead (verb)
transitive verb
to cover, line, or weight with lead - (see lead)
to fix (window glass) in position with - leads
to put space between the lines of (typeset matter)
to treat or mix with lead or a lead compound - leaded gasoline
Lead (Wikipedia)
This article is about the metal. For other uses, see Lead (disambiguation).
Lead,  82Pb
Lead electrolytic and 1cm3 cube.jpg
General properties
Name, symbol lead, Pb
Pronunciation /ˈlɛd/
Appearance metallic gray
Lead in the periodic table
Hydrogen (diatomic nonmetal)
Helium (noble gas)
Lithium (alkali metal)
Beryllium (alkaline earth metal)
Boron (metalloid)
Carbon (polyatomic nonmetal)
Nitrogen (diatomic nonmetal)
Oxygen (diatomic nonmetal)
Fluorine (diatomic nonmetal)
Neon (noble gas)
Sodium (alkali metal)
Magnesium (alkaline earth metal)
Aluminium (post-transition metal)
Silicon (metalloid)
Phosphorus (polyatomic nonmetal)
Sulfur (polyatomic nonmetal)
Chlorine (diatomic nonmetal)
Argon (noble gas)
Potassium (alkali metal)
Calcium (alkaline earth metal)
Scandium (transition metal)
Titanium (transition metal)
Vanadium (transition metal)
Chromium (transition metal)
Manganese (transition metal)
Iron (transition metal)
Cobalt (transition metal)
Nickel (transition metal)
Copper (transition metal)
Zinc (transition metal)
Gallium (post-transition metal)
Germanium (metalloid)
Arsenic (metalloid)
Selenium (polyatomic nonmetal)
Bromine (diatomic nonmetal)
Krypton (noble gas)
Rubidium (alkali metal)
Strontium (alkaline earth metal)
Yttrium (transition metal)
Zirconium (transition metal)
Niobium (transition metal)
Molybdenum (transition metal)
Technetium (transition metal)
Ruthenium (transition metal)
Rhodium (transition metal)
Palladium (transition metal)
Silver (transition metal)
Cadmium (transition metal)
Indium (post-transition metal)
Tin (post-transition metal)
Antimony (metalloid)
Tellurium (metalloid)
Iodine (diatomic nonmetal)
Xenon (noble gas)
Caesium (alkali metal)
Barium (alkaline earth metal)
Lanthanum (lanthanide)
Cerium (lanthanide)
Praseodymium (lanthanide)
Neodymium (lanthanide)
Promethium (lanthanide)
Samarium (lanthanide)
Europium (lanthanide)
Gadolinium (lanthanide)
Terbium (lanthanide)
Dysprosium (lanthanide)
Holmium (lanthanide)
Erbium (lanthanide)
Thulium (lanthanide)
Ytterbium (lanthanide)
Lutetium (lanthanide)
Hafnium (transition metal)
Tantalum (transition metal)
Tungsten (transition metal)
Rhenium (transition metal)
Osmium (transition metal)
Iridium (transition metal)
Platinum (transition metal)
Gold (transition metal)
Mercury (transition metal)
Thallium (post-transition metal)
Lead (post-transition metal)
Bismuth (post-transition metal)
Polonium (post-transition metal)
Astatine (metalloid)
Radon (noble gas)
Francium (alkali metal)
Radium (alkaline earth metal)
Actinium (actinide)
Thorium (actinide)
Protactinium (actinide)
Uranium (actinide)
Neptunium (actinide)
Plutonium (actinide)
Americium (actinide)
Curium (actinide)
Berkelium (actinide)
Californium (actinide)
Einsteinium (actinide)
Fermium (actinide)
Mendelevium (actinide)
Nobelium (actinide)
Lawrencium (actinide)
Rutherfordium (transition metal)
Dubnium (transition metal)
Seaborgium (transition metal)
Bohrium (transition metal)
Hassium (transition metal)
Meitnerium (unknown chemical properties)
Darmstadtium (unknown chemical properties)
Roentgenium (unknown chemical properties)
Copernicium (transition metal)
Nihonium (unknown chemical properties)
Flerovium (unknown chemical properties)
Moscovium (unknown chemical properties)
Livermorium (unknown chemical properties)
Tennessine (unknown chemical properties)
Oganesson (unknown chemical properties)


Atomic number (Z) 82
Group, block group 14 (carbon group), p-block
Period period 6
Element category   post-transition metal
Standard atomic weight (Ar) 207.2(1)
Electron configuration [Xe] 4f14 5d10 6s2 6p2
Electrons per shell
2, 8, 18, 32, 18, 4
Physical properties
Phase solid
Melting point 600.61 K ​(327.46 °C, ​621.43 °F)
Boiling point 2022 K ​(1749 °C, ​3180 °F)
Density near r.t. 11.34 g/cm3
when liquid, at m.p. 10.66 g/cm3
Heat of fusion 4.77 kJ/mol
Heat of vaporization 179.5 kJ/mol
Molar heat capacity 26.650 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 978 1088 1229 1412 1660 2027
Atomic properties
Oxidation states 4, 3, 2, 1, −1, −2, −4 ​(an amphoteric oxide)
Electronegativity Pauling scale: 1.87 (+2)
Ionization energies 1st: 715.6 kJ/mol
2nd: 1450.5 kJ/mol
3rd: 3081.5 kJ/mol
Atomic radius empirical: 175 pm
Covalent radius 146±5 pm
Van der Waals radius 202 pm
Crystal structure face-centered cubic (fcc)
Face-centered cubic crystal structure for lead
Speed of sound thin rod 1190 m/s (at r.t.) (annealed)
Thermal expansion 28.9 µm/(m·K) (at 25 °C)
Thermal conductivity 35.3 W/(m·K)
Electrical resistivity 208 nΩ·m (at 20 °C)
Magnetic ordering diamagnetic
Magnetic susceptibility (χmol) −23.0·10−6 cm3/mol (at 298 K)
Young's modulus 16 GPa
Shear modulus 5.6 GPa
Bulk modulus 46 GPa
Poisson ratio 0.44
Mohs hardness 1.5
Brinell hardness 38–50 MPa
CAS Number 7439-92-1
Discovery by Middle Easterns (7000 BCE)
Most stable isotopes of lead
iso NA half-life DM DE (MeV) DP
202Pb syn 53000 y ε 0.0497 202Tl
204Pb 1.4% is stable with 122 neutrons
205Pb trace 1.53×107 y ε 0.051 205Tl
206Pb 24.1% is stable with 124 neutrons
207Pb 22.1% is stable with 125 neutrons
208Pb 52.4% is stable with 126 neutrons
210Pb trace 22.3 y β 0.064 210Bi
| references | in Wikidata

Lead is a chemical element with atomic number 82 and symbol Pb (after the Latin plumbum). When freshly cut, it is bluish-white; it tarnishes to a dull gray upon exposure to air. It is a soft, malleable, and heavy metal with a density exceeding that of most common materials. Lead has the second-highest atomic number of the classically stable elements and lies at the end of three major decay chains of heavier elements.

Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature (lead and lead oxides react with both acids and bases) and tendency to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state, rather than the +4 common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the group, lead exhibits a tendency to bond to itself; it can form chains, rings, and polyhedral structures.

Lead is easily extracted from its ores and was known to prehistoric people in Western Asia. A principal ore of lead, galena, often bears silver, and interest in silver helped initiate widespread lead extraction and use in ancient Rome. Lead production declined after the fall of Rome and did not reach comparable levels again until the Industrial Revolution. Nowadays, global production of lead is about ten million tonnes annually; secondary production from recycling accounts for more than half of that figure.

Lead has several properties that make it useful: high density, low melting point, ductility, and relative inertness to oxidation. Combined with relative abundance and low cost, these factors resulted in the extensive use of lead in construction, plumbing, batteries, bullets and shot, weights, solders, pewters, fusible alloys, and radiation shielding. In the late 19th century, lead was recognized as poisonous, and since then it has been phased out for many applications. Lead is a neurotoxin that accumulates in soft tissues and bones, damaging the nervous system and causing brain disorders and, in mammals, blood disorders.

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