Bismuth

Bismuth, Bi, is a metallic main group element, found in Group Vb of the periodic table.

Atomic Number : 83
Relative Atomic Mass : 208.98
Melting Point : 271 degC.

Discovery

Bismuth was described by J H Pott in 1793AD.
Bismuth and its reactions were described by C J Geoffroy in 1753AD.

Occurrence

Bismuth is found as the element in fairly pure state in many locations. Other ores include

Bismuthite or Bismuth Glance, Bi2S3,
Tetradymite, Bi2Te3, and
Bismite or Bismuth Ochre, Bi2O3.

Extraction

Bismuth is extracted from its sulphide ores by roasting, to form bismuth oxide.


	2 Bi2S3   +   9 O2   ==>   2 Bi2O3    +   6 SO2

The bismuth oxide is then reduced with carbon to form the metal.


	2 Bi2O3   +   3 C   ==>   4 Bi    +   3 CO2

Preparation

Manufacture

Properties

Bismuth is

a grayish white silvery solid with a faint reddish tinge,
has the lowest thermal conductivity of all metals, except mercury,
has lowest electrical conductivity, and exhibits a Hall Effect, and
expands on solidification.

Reactions

Bismuth is similar in to Arsenic in its chemical properties.

Bismuth burns when heated in air, forming bismuth oxide.
Bismuth reacts with sulphur and the halogens forming compounds where the valency of the element is three.

Uses

Bismuth is used mainly in the manufacture of fusible alloys (i.e. allows which melt at a low temperature), which are used in fire-protection systems.
Bismuth is used in thermopiles.

Detection and Analysis

Bismuth is detected by the orange coloured precipitate that is formed when hydrogen sulphide is passed into an acidified solution of the substance under test.

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