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Lanthanum usually occurs together with cerium and the other rare earth elements. Lanthanum was first found by the Swedish chemist Carl Gustaf Mosander in 1839 as an impurity in cerium nitrate – hence the name lanthanum, from the ancient Greek λανθάνειν (lanthanein), meaning 'to lie hidden'.
Lanthanum(III) oxide, also known as lanthana, chemical formula La 2 O 3, is an inorganic compound containing the rare earth element lanthanum and oxygen. It is used in some ferroelectric materials, as a component of optical materials, and is a feedstock for certain catalysts, among other uses.
The CuTi 2 structure of the lanthanum, cerium and praseodymium diiodides along with HP-NdI 2 contain 4 4 nets of metal and iodine atoms with short metal-metal bonds (393-386 La-Pr). [10] these compounds should be considered to be two-dimensional metals (two-dimensional in the same way that graphite is). The salt-like dihalides include those of ...
Pages in category "Lanthanum minerals" The following 5 pages are in this category, out of 5 total. This list may not reflect recent changes. A. Astrocyanite-(Ce) B.
The nitrides can be prepared by the reaction of lanthanum metals with nitrogen. Some nitride is produced along with the oxide, when lanthanum metals are ignited in air. [ 18 ] Alternative methods of synthesis are a high temperature reaction of lanthanide metals with ammonia or the decomposition of lanthanide amides, Ln(NH 2 ) 3 .
Caesium-134 is found in spent nuclear fuel but is not produced by nuclear weapon explosions, as it is only formed by neutron capture on stable Cs-133, which is only produced by beta decay of Xe-133 with a half-life of 3 days. Cs-134 has a half-life of 2 years and may be a major source of gamma radiation in the first 20 years after discharge.
Naturally occurring lanthanum (57 La) is composed of one stable (139 La) and one radioactive (138 La) isotope, with the stable isotope, 139 La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138 La, with a half-life of 1.03×10 11 years; 137 La, with a half ...
The early lanthanides, including neodymium, as well as lanthanum, cerium and praseodymium, have been found to be essential to some methanotrophic bacteria living in volcanic mudpots, such as Methylacidiphilum fumariolicum. [81] [82] Neodymium is not otherwise known to have a biological role in any other organisms. [83]