Tennessine astatine is estimated to be between 6.2 and 6.5 g/cm. The known isotopes of tennessine, Ts and Ts, are too short-lived to allow for chemical experimentation at present. Nevertheless, many chemical properties of tennessine have been calculated. Unlike the previous group 17 elements, tennessine may not exhibit the chemical behavior common to the halogens. For example, fluorine, chlorine, bromine, and iodine routinely accept an electron to achieve the more stable electronic configuration of a noble gas, obtaining eight electrons (octet) in their valence shells instead of seven. This ability weakens as atomic weight increases going down the group; tennessine would
Bromine their oxides: as such, it is used to oxidise uranium to uranium hexafluoride in the nuclear industry. Refractory oxides tend to be only partially fluorinated, but here the derivatives KBrF and BrFSbF remain reactive. Bromine trifluoride is a useful nonaqueous ionising solvent, since it readily dissociates to form and and thus conducts electricity. Bromine pentafluoride (BrF) was first synthesised in 1930. It is produced on a large scale by direct reaction of bromine with excess fluorine at temperatures higher than 150 °C, and on a small scale by the fluorination of potassium bromide at 25 °C. It is a very