neodymium

 Nhan Phan Ms.Marx Chemistry project

Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal which tarnishes in air. Neodymium was discovered in 1885. The Atomic weight is 144.242. This element’s color is silvery white and yellowish tinge. The proton and electron are 60; it always has the same number because an atom is neutral. The neutron is 84. The electron configuration is [Xe] 4f4. It is present in significant quantities in the ore minerals monazite. Neodymium is not found naturally in metallic form or unaccompanied by other lanthanoids and it is usually refined for general use. Neodymium has several important applications: it is a constituent of neodymium magnets, which are widely used in motors, loudspeakers and numerous appliances. Neodymium is a popular additive in glass, giving it a characteristic reddish-purple color; this glass is used in lasers emitting infrared light with the wavelength of 1.054-1.062 micrometers. Neodymium is also used in Nd: YAG lasers to generate 1.064 micrometer light. This is one of the most significant solid state lasers. Neodymium is a key component of an alloy used to make high-power lightweight magnets for electric motors of hybrid cars, and ingenerators for wind turbines.

Physical Neodymium, a rare earth metal, was present in classical mischmetal to the extent of about 18%. The metal has a bright, silvery metallic luster; however, as one of the more reactive rare earth ( lanthanide ) metals, it quickly oxidizes in air. The oxide layer then falls off, which exposes the metal to further oxidation. Thus a centimeter-sized Nd sample completely oxidizes within a year. Neodymium exists in two allotropic forms, with a transformation from a double hexagonal to a body-centered cubic structure taking place at 863 °C. Chemical Neodymium metal tarnishes slowly in air and burns readily at 150 °C to form neodymium(III) oxide : 4 Nd + 3 O2 → 2 Nd2O3 Neodymium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form neodymium hydroxide: 2 Nd (s) + 6 H2O (l) → 2 Nd(OH)3 (aq) + 3 H2 (g) 1. Neodymium metal reacts with all the halogens: 2 Nd (s) + 3 F2 (g) → 2 NdF3 (s) [violet] 2 Nd (s) + 3 Cl2 (g) → 2 NdCl3 (s) [mauve] 2 Nd (s) + 3 Br2 (g) → 2 NdBr3 (s) [violet] 2 Nd (s) + 3 I2 (g) → 2 NdI3 (s) [green] 2. Neodymium dissolves readily in dilute sulfuric acid to form solutions containing the lilac Nd(III) ions, which exist as a [Nd(OH2)9]3+ complexes: 2 Nd (s) + 3 H2SO4 (aq) → 2 Nd3+ (aq) + 3 SO2−4 (aq) + 3 H2 (g) Compounds 3. Neodymium compounds include Isotopes //Main article:// // Isotopes of neodymium // Naturally occurring neodymium is composed of 5 stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd, with 142Nd being the most abundant (27.2% natural abundance ), and 2 radioisotopes , 144Nd and 150Nd. In all, 31 radioisotopes of neodymium have been characterized up to now, with the most stable being naturally occurring isotopes 144Nd ( alpha decay, a half-life (T½) of 2.29×1015 years) and 150Nd ( double beta decay , T½ of 7×1018 years). All of the remaining radioactive isotopes have half-lives that are less than 11 days, and the majority of these have half-lives that are less than 70 seconds. This element also has 13 known Meta states with the most stable being 139//m//Nd (T½ 5.5 hours), 135//m//Nd (T½ 5.5 minutes) and 133//m//1Nd (T½ ~70 seconds). The primary decay modes before the most abundant stable isotope, 142Nd, are electron capture and positron decay, and the primary mode after is beta minus decay. The primary decay products before 142Nd are element Pr ( praseodymium ) isotopes and the primary products after are element Pm ( promethium ) isotopes.
 * Halides: NdF3, NdCl3 , NdBr3 , NdI3
 * Oxides: Nd2O3
 * Sulfides: NdS, Nd2S3
 * Nitrides: NdN

History
Neodymium was discovered by Baron Carl Auer von Welsbach, an Austrian chemist , in Vienna in 1885. Mossander separated a previously unidentified rose coloured oxide from cerite in 1841. He believed that the oxide contained a new element which he names didymium, as it was the inseparable twin brother of lanthanum. Although, von Welsbach successfully separated didymium into two elemental components, neodymia and praseodymia in 1885, it was not until 1925, when neodymium was separated into a raltively pure form. It can be refined by separating neodymium salts from other rare earths by ion-exchange or solvent extraction. Alternatively it can be obtained by the reduction of anhydrous halides such as NdF3 using calcium metal, while other separation methods are also available. Neodymium is also used in magnets. Such magnets are used in items such as computer disk drives.

Precautions
Neodymium metal dust is a combustion and explosion hazard. Neodymium compounds, as with all rare earth metals, are of low to moderate toxicity; however its toxicity has not been thoroughly investigated. Neodymium dust and salts are very irritating to the eyes and mucous membranes, and moderately irritating to skin. Breathing the dust can cause lung embolisms, and accumulated exposure damages the liver. Neodymium also acts as an anticoagulant, especially when given intravenously. Neodymium magnets have been tested for medical uses such as magnetic braces and bone repair, but biocompatibility issues have prevented widespread application. Commercially available magnets made from neodymium are exceptionally strong, and can attract each other from large distances. If not handled carefully, they could come together very quickly and forcefully, causing injuries. For example, a person lost part of his finger when two magnets he was using snapped together from 50 cm away. Another danger is when two such magnets snap together, the force of the collision can cause them to shatter, sending sharp pieces flying around, potentially causing serious injuries.