Bismuth

Bismuth is a chemical element. It is element 83 on the periodic table and its symbol is Bi. Its atomic mass is 209. It is only slightly radioactive. The radioactivity is minimal so it is typically seen as nonradioactive. Bismuth is only naturally found as one isotope, which is the almost nonradioactive one. Its radioactivity was predicted by scientists and proven by analyzing the metal. It is in Group 15 on the periodic table.

Bismuth, ₀₀Bi

Bismuth
Pronunciation	/ˈbɪzməθ/ ​(BIZ-məth)
Appearance	lustrous brownish silver
Standard atomic weight Ar°(Bi)
	208.98040(1)
Bismuth in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Sb ↑ Bi ↓ Mc lead ← bismuth → polonium
Group	group 15 (pnictogens)
Period	period 6
Block	p-block
Electron configuration	[Xe] 4f14 5d10 6s2 6p3
Electrons per shell	2, 8, 18, 32, 18, 5
Physical properties
Phase at STP	solid
Melting point	544.7 K ​(271.5 °C, ​520.7 °F)
Boiling point	1837 K ​(1564 °C, ​2847 °F)
Density (near r.t.)	9.78 g/cm3
when liquid (at m.p.)	10.05 g/cm3
Heat of fusion	11.30 kJ/mol
Heat of vaporization	179 kJ/mol
Molar heat capacity	25.52 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 941 1041 1165 1325 1538 1835
Atomic properties
Oxidation states	−3, −2, −1, 0, +1, +2, +3, +4, +5 (a mildly acidic oxide)
Electronegativity	Pauling scale: 2.02
Ionization energies	1st: 703 kJ/mol 2nd: 1610 kJ/mol 3rd: 2466 kJ/mol (more)
Atomic radius	empirical: 156 pm
Covalent radius	148±4 pm
Van der Waals radius	207 pm
Spectral lines of bismuth
Other properties
Natural occurrence	primordial
Crystal structure	​rhombohedral
Speed of sound thin rod	1790 m/s (at 20 °C)
Thermal expansion	13.4 µm/(m⋅K) (at 25 °C)
Thermal conductivity	7.97 W/(m⋅K)
Electrical resistivity	1.29 µΩ⋅m (at 20 °C)
Magnetic ordering	diamagnetic
Molar magnetic susceptibility	−280.1·10−6 cm3/mol
Young's modulus	32 GPa
Shear modulus	12 GPa
Bulk modulus	31 GPa
Poisson ratio	0.33
Mohs hardness	2.25
Brinell hardness	70–95 MPa
CAS Number	7440-69-9
History
Discovery	Arabic alchemists (before AD 1000)
Isotopes of bismuth
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 207Bi synth 31.55 y β+ 207Pb 208Bi synth 3.68×105 y β+ 208Pb 209Bi 100% 2.01×1019 y α 205Tl 210Bi trace 5.012 d β− 210Po α 206Tl 210mBi synth 3.04×106 y IT 210Bi α 206Tl

Bismuth

Properties

Physical properties

Bismuth crystals can have a thin layer of bismuth(III) oxide on the outside that is very colorful.

Bismuth is a silver metal with a pink tinge to it. This pink color is because of its oxide coating. Bismuth is a post-transition metal. It is one of the strongest diamagnetic metals. It is almost as heavy as lead. It is quite brittle. It can make crystals with a shiny surface. Its melting point is quite low: 271.5 °C (520.7 °F), which is normal for post-transition metals. As a liquid it is denser and has a smaller volume than as a solid. Another chemical that does this is water. It does not conduct electricity or heat very well.

Chemical properties

Bismuth is somewhat similar to antimony. Bismuth makes a thin coating of bismuth(III) oxide when it is in air. This makes the colors on the crystals. It does not oxidize any more than the oxide layer. It burns when powdered with a bright blue flame, making yellow bismuth(III) oxide fumes. Bismuth also reacts with sulfur, when molten. Bismuth reacts with nitric acid to make bismuth(III) nitrate and concentrated sulfuric acid to make bismuth(III) sulfate and sulfur dioxide. It reacts with halogens to make bismuth(III) halides but with fluorine it makes bismuth(V) fluoride unless the fluorine is diluted.

Chemical compounds

Bismuth forms chemical compounds in two main oxidation states: +3 and +5. +3 is more common. +3 compounds are weak oxidizing agents and are normally light yellow. +5 compounds are strong oxidizing agents. Bismuthates are the most common +5 compounds. Bismuth(V) fluoride is another +5 compound. Bismuth(V) oxide is an unstable red solid. Bismuth sulfide is a common ore of bismuth. Bismuthine, a bismuth hydride, is very unstable and only can be made at very cold temperatures. Bismuth makes many oxy- compounds like bismuth oxychloride. These compounds are made when bismuth halides dissolve in water.

Trioxides

Further information: Bismuth(III) oxide

+3 compounds are weak oxidizing agents except for bismuthine. They are normally pale yellow.

• Bismuthine, unstable gas
• Bismuth(III) bromide, pale yellow solid
• Bismuth(III) chloride, pale yellow solid
• Bismuth(III) fluoride, gray white solid
• Bismuth(III) iodide, dark gray solid
• Bismuth(III) oxide, pale yellow solid
• Bismuth(III) oxychloride, whitish solid
• Bismuth(III) sulfide, brown solid

Pentoxides

Bismuth(V) oxides (+5 compounds) are very strong oxidizing agents. Its chemical formula is Bi₂O₅. It is a scarlet red solid. It decomposes to bismuth(III) oxide and oxygen easily. It is made by electrolysis of bismuth(III) oxide in a hot concentrated alkali like sodium hydroxide.

• Bismuth(V) fluoride, colorless solid
• Bismuth(V) oxide, unstable red solid
• Bismuthate, the ion
• Sodium bismuthate, light brown solid, insoluble in water

• 
  Bismuth(III) oxide
• 
  Bismuth(III) sulfide
• 
  Bismuth(III) nitrate
• 
  Bismuth(III) chloride
• 
  Sodium bismuthate

History

Bismuth was known since ancient times. It was confused with tin and lead, though. No one is credited for discovering bismuth. In the 1500s, people started realizing that bismuth was different than tin or lead.

Occurrence

• 
  Bismite
• 
  Bismuth as a mineral
• 
  Bismuthinite

Bismuth is not very common in the earth. It is only about twice as common as gold. Bismite, a bismuth oxide mineral, and bismuthinite, a bismuth sulfide, are two common ores. Bismuth is sometimes found as a metal, too.

Preparation

Bismuth and its minerals are too rare to be mined. They are gotten by "secondary extraction". It is normally found in lead metal. The lead metal is purified by electrolysis, leaving the bismuth behind as a sludge on the bottom of the container. The copper is taken out of the sludge and the bismuth is purified by being reduced in a furnace and all the impurities are filtered out.

China makes the most bismuth. Peru, Mexico, and Japan also make bismuth.

Bismuth can be recycled, but the process is challenging in many regions. This difficulty arises because bismuth is often used in applications such as bullets, solder, and stomach medications, which tend to disperse widely and are not easily recoverable.

Uses

As an element

Bismuth is used in alloys with very low melting points. Some of them melt in hot water. They are also found in solder that does not have lead in it. It can make alloys with other metals to make them more malleable. It is also used in bullets to replace lead. In some places lead bullets are outlawed as birds eat them and get lead poisoning. It is also used in alloys for plumbing. It is used in fishing sinkers.

As chemical compounds

Bismuth is used in some medicines such as Pepto-Bismol. This medicine has bismuth subsalicylate in it. It is also used as an internal deodorant and to treat eye infections and peptic ulcers.

Bismuth oxychloride is used in cosmetics. Bismuth telluride is used in electronic thermometers. Another compound is used in superconductors and becomes a superconductor at a high temperature. It can be used as a pigment and in fireworks to make crackling sounds. It is used in the nuclear fuel of a nuclear reactor.

Safety

Bismuth is much less toxic than other heavy metals. This is why it is replacing lead in many things. It does not add up in the body like other heavy metals do. A very large amount of bismuth can poison the kidneys and liver, though. Because its oxide does not dissolve in water, it is considered safe for the environment. Bismuth's radioactivity is so weak that it's not considered a hazard.