Dysprosium

Symbol: Dy
Atomic number: 66
Category: lanthanides
Group: n/a
Period: 6
Block: f
Atomic weight: 162.500 g/mol
Electrons per shell: 2, 8, 18, 28, 8, 2
CAS number: 7429-91-6
Phase: solid
Density: 8.540 kg/dm³ (near room temperature)
Melting point: 1680 K (1407 °C, 2565 °F)
Boiling point: 2840 K (2562 °C, 4653 °F)
Crystal structure: hexagonal
Oxidation states: 3
Electronegativity: 1.22 (Pauling scale)
Name's origin: dysprositos
Name's meaning: a Greek word which means 'hard to get' - the discoverer tried to isolate the element more than 30 times
Facts:
- is a rare earth element with a metallic silver luster
- is never found in nature as a free element, though it is found in various minerals, such as xenotime
- is relatively stable in air at room temperature, but it dissolves readily in dilute sulfuric acid to form solutions containing the yellow Dy(III) ions, which exist as a [Dy(OH₂)₉]³⁺ complex
- is used for its high thermal neutron absorption cross-section in making control rods in nuclear reactors, for its high magnetic susceptibility to magnetization in data storage devices and as a component of Terfenol-D (a metal alloy)
- soluble dysprosium salts are mildly toxic, while the insoluble salts are considered non-toxic
- has no known biological role
- most dysprosium is being obtained from the ion-adsorption clay ores of southern China
- is used, in conjunction with vanadium and other elements, in making laser materials
- Dy powder may present an explosion hazard when mixed with air and when an ignition source is present
- dysprosium fires cannot be put out by water - it can react with water to produce flammable hydrogen gas