Thallium
Symbol
Tl
Atomic Number
81
Atomic Weight
204.3833
Element Classification
Discovered By
Sir William Crookes
Discovery Date
1861 (England)
Name Origin
Greek: thallos (green twig), for a bright green line in its spectrum.
Density(g/cc)
11.85
Melting Point
576.6
Boiling Point(K)
1730
Appearance
Soft, gray metal
Atomic Radius(pm)
171
Atomic Volume(cc/mol)
17.2
Covalent Radius(pm)
148
Ionic Radius
95 (+3e) 147 (+1e)
Specific Heat
0.128
Fusion Heat
4.31
Evaporation Heat(kj/mol)
162.4
Thermal Conductivity(@25°C W/m K)
46.1
Debye Temperature
96.00
Pauling Negativity Number
1.62
First Ionizing Energy(kj/mol)
588.9
Oxidation States
3, 1
Electronic Configuration
[Xe] 4f14 5d10 6s2 6p1
Lattice Structure
Hexagonal(HEX)
Lattice Constant
3.460
Lattice C/A Ratio
1.599
