I originally reviewed What Color Is Your Parachute? in five parts, which you can find here, here, here, here, and here if you would like to read the original comments. What Color Is Your Parachute? is the eighteenth of fifty-two books in The Simple Dollarâs series 52 Personal Finance Books in 52 Weeks.
Thallium is extremely soft, malleable and sectile enough to be cut with a knife at room temperature. It has a metallic luster that, when exposed to air, quickly tarnishes to a bluish-gray tinge, resembling lead. It may be preserved by immersion in oil. A heavy layer of oxide builds up on thallium if left in air.
Thallium is the first element in group 13 where the reduction of the +3 oxidation state to the +1 oxidation state is spontaneous under standard conditions. Since bond energies decrease down the group, by thallium, the energy released in forming two additional bonds and attaining the +3 state is not always enough to outweigh the energy needed to involve the 6s-electrons.