About the sample
This thallium sample was kept in paraffin oil and it was with dark color with corrosion layer. It was cleaned with hexane from the oil and then with concentrated nitric acid. A narrow test tube was filled with argon meanwhile. Then, quickly, thallium sample was cleaned with isopropyl alcohol, acetone and hexane, dried with a paper and placed in the test tube with argon. The noble gas argon should preserve the sample from the influence of oxygen and ability to transfer it to oxide and moisture from the air to turn it into hydroxide.
Thallium is soft metal and can be cut with a knife. It is highly poisonous and it may cause cancer. This sample has been donated from the private collection of Metodija Najdoski.  
ρ / g/cm311.85
tt, mp / °C304
tv, bp / °C1473
Electronegativity, (X)1.62
Crystal structureHexagonal
Extended informationhttps://www.webelements.com/thallium/