INTRODUCTION
Thallium from the Greek word thallos, 'young shoot' is a soft, malleable metallic element that acquires a bluish-gray color upon exposure to the atmosphere. It has a high index of refraction.
It occurs in combination with pyrites, zinc blende, and hematite and is often recovered from the flue dust produced by pyrite ovens in which sulfur and iron are separated.
BASIC INFORMATIONS
- Atomic Number
- 81
- Atomic Mass
- 204.382
- Atomic radius
- 0.155
- Ionization energy
- 589
- Electronic config
- 2,8,18,32,18,3
- Principal Valency
- +3
- Density g/cm³
- 11.83
- Melting point °C
- 304
- Boiling point °C
- 1473
- Type of Element
- Metal
- Electronegativity
- 1.8
- Element Category
- Boron Family
- Appearance
- White solid
- Block
- p-block
- Period
- 6
- Group
- 13
- No of Isotopes
- 37
- Occurrence
- Combine form
- Abundance in ppm
- 0.7
- Year of Discovery
- 1861
EXTRACTION
It is recovered from the flue dust produced by pyrite ovens.
OXIDATION STATES
+3,+2,+1 (Mildly basic)
MAJOR SOURCE
Pyrites, Zinc blende, Hematite
EXAMPLES OF COMPOUND PRESENT
Thallous oxide, Thallous chloride, Thallic chloride
ECONOMIC IMPORTANCE
* Thallium-activated sodium iodide crystals are used in some portable scintillation counters to detect gamma radiation.
* When alloyed with mercury, it is used in low-temperature thermometers, relays, and switches.
* Thallium bromoiodide crystals and thallium oxysulfide crystals is employed extensively in military communication systems.
* Thallium salts, which burn with a bright green flame, are used in rockets and flares.
