Bismuth (Bi)

Stable Isotopes of Bismuth

Isotope Z(p) N(n) Atomic Mass Natural Abundance Nuclear Spin
Bi-209  83  126  208.980384 100.00%  9/2- 



In early times, bismuth was often confused with tin and lead because of its similarities to those elements. In 1753, Claude Geoffroy the Younger demonstrated its distinctness from lead. It takes its name from the German word bisemutum.Miners in the age of alchemy also gave bismuth the name tectum argenti, or “silver being made,” in the sense of silver still in the process of being formed within the earth.

Bismuth is a crystalline, brittle, soft metal, grayish-white with a pinkish tinge and a metallic luster. It has a rhombohedral crystal system. It is soluble in nitric and hydrochloric acids. Its thermal conductivity is lowest of all metals except mercury. It forms trivalent and pentavalent compounds (the trivalent compounds are more common). Many of bismuth's chemical properties are similar to those of other elements in its group, especially arsenic and antimony. It is stable in both dry and moist air at ordinary temperatures; at elevated temperatures, the vapors of the metal combine rapidly with oxygen, forming bismuth trioxide. Bismuth reacts with chlorine, bromine and iodine vapors, forming their bismuth halides.

The major commercial applications of bismuth are as fusible alloys and in pharmaceuticals. Some bismuth compounds also find catalytic applications in the manufacture of acrylic fibers. It is used in electric fuses, fusible boiler plugs, low-melting solders, thermoelectric materials and semiconductors, and as an additive to steel and other metals. Other compounds are used in medicine as antacids, antisyphilitics and anti-infectives, and in cosmetics such as lipstick, powder and eye shadow.

Properties of Bismuth

Name Bismuth 
Symbol Bi 
Atomic number 83 
Atomic weight 208.98 
Standard state Solid at 298 °K 
CAS Registry ID 7440-69-9 
Group in periodic table 15 
Group name Pnictogen 
Period in periodic table
Block in periodic table p-block 
Color Lustrous reddish-white 
Classification Metallic 
Melting point 271 °C
Boiling point 1560 °C
Vaporization point 1564 ºC
Thermal conductivity 8 W/(m·K)
Electrical resistivity 106.8 µΩ·cm at 0 °C 
Electronegativity 1.67 
Specific heat 122 J/(kg·K)
Heat of vaporization 160 kJ·mol-1
Heat of fusion 10.9 kJ·mol-1
Density of liquid 10.05 g/cm3 at 271 °C
Density of solid 9.79 g/cm3
Electron configuration [Xe]4f145d106s26p3 
Atomic radius 1.88 Å (coordination number 12) 
Atomic volume 21.3 cm3/g-atom
Ionic radii in crystals corresponding to coordination number 6 Bi3+: 1.03 Å; Bi5+: 0.76 Å
Ionization potentials Bi(+3) 25.56 eV and
Bi(+5) 56.0 eV
Electron affinity 0.946 eV
Oxidation states  +3, +5 

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