Terbium (Tb), chemical element, a rare-earth metal of the lanthanide series of the periodic table.
Terbium is a moderately hard, silvery white metal that is stable in air when in pure form. The metal is relatively stable in air even at high temperatures, because of formation of a tight, dark oxide layer that can be represented as a mixed oxide composed of Tb2O3 and TbO2. Terbium readily reacts with diluted acids, but it is insoluble in hydrofluoric acid (HF) because the presence of the fluoride ion protects the metal from further reaction by forming a protective layer of TbF3. The metal is a very strong paramagnet above 230 K (−43 °C, or −46 °F); it is antiferromagnetic between 220 K (−53 °C, or −64 °F) and 230 K, and it becomes ferromagnetic below 220 K.
The element was discovered in 1843 by Swedish chemist Carl Gustaf Mosander in a heavy rare-earth fraction called yttria, but its existence was not confirmed for at least 30 years, and pure compounds were not prepared until 1905. Terbium occurs in many rare-earth minerals but is almost exclusively obtained from bastnasite and from laterite ion-exchange clays. It is also found in the products of nuclear fission. Terbium is one of the least abundant of the rare earths; its abundance in Earth’s crust is about the same as thallium.
Terbium compounds are used as green phosphors in fluorescent lamps, computer monitors(hence the picture for the element), and TV screens that use cathode-ray tubes. Another major use is with dysprosium and iron in the magnetostrictive alloy Terfenol-D (Tb0.3Dy0.7Fe2), which is a component of magnetically controlled actuators, sonar systems, and pressure sensors. Together with another lanthanide—gadolinium—terbium was used by Geoffrey Green and coworkers in 1990 to build a dual-stage room-temperature magnetic refrigerator prototype, with gadolinium as a high-temperature stage and terbium as a low-temperature stage.
Terbium is one of a few rare earths that have a +4 as well as a +3 oxidation state; the former is a result of stability of the half-filled 4f shell. The brown oxide prepared by air ignition has the approximate formula Tb4O7; the oxide TbO2 is obtained by using atomic oxygen. The tetrafluoride TbF4 is prepared by fluorinating the trifluoride; the Tb4+ ion is not known in solution. In other salts and in solution, terbium is present in the +3 oxidation state and behaves as a typical rare earth. Its solutions are pale pink to colourless.
Homeopathy
Stage 11: Terbium
Terbium is a great remedy for one who has to maintain his power. He has to go on and cannot relax out of fear it will slip through his fingers.
The focus of the Lanthanides is on self-control and inner strength. Their efforts are directed toward achieving strength of mind.
In those deficient in Terbium, they need to keep control over themselves. They appear confident but being out of control is a serious issue, so they often get into yoga and other disciplines.
When out of balance they can be very controlling (they can be a pain in the butt, to put it bluntly). This can develop when they are responsible for a situation that seems to be right at the limits of their capacity. So everything has to be perfect. Again, just like other Stage 11 remedies, the accounts have to be checked and balanced, and they have to show a profit. Only then can they can enjoy life! The nit-picking conflicts they tend to create in difficult times can be very irritating. When their troubles are acknowledged they begin to trust others and learn to delegate.
Terbium relaxes all this tension allowing the original autonomous personality to come shining through. Autonomy and self-respect need not depend on anything. Others are capable of autonomy too, and that the river still flows without their help!
The physical tension in this remedy can very intense indeed
