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A lanthanum hexaboride hot cathode. Lanthanum hexaboride cathodes. Lanthanum hexaboride powdered. Lanthanum hexaboride (La B 6, also called lanthanum boride and LaB) is an inorganic chemical, a boride of lanthanum. It is a refractory ceramic material that has a melting point of 2210 °C, and is insoluble in water and hydrochloric acid. [1]
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 ...
Cerium hexaboride (Ce B 6, also called cerium boride, CeBix, CEBIX, and (incorrectly) CeB) is an inorganic chemical, a boride of cerium. It is a refractory ceramic material. It has a low work function, one of the highest electron emissivities known, and is stable in vacuum. The principal use of cerium hexaboride is a coating of hot cathodes. It ...
The term derives from lanthanum, first discovered in 1838, at that time a so-called new rare-earth element "lying hidden" or "escaping notice" in a cerium mineral, [12] and it is an irony that lanthanum was later identified as the first in an entire series of chemically similar elements and gave its name to the whole series.
The mean oxidation number for the boron atoms is then simply the ratio of hydrogen to boron in the molecule. For example, in diborane B 2 H 6, the boron oxidation state is +3, but in decaborane B 10 H 14, it is 7 / 5 or +1.4. In these compounds the oxidation state of boron is often not a whole number.
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 Avogadro constant, commonly denoted N A [1] or L, [2] is an SI defining constant with an exact value of 6.022 140 76 × 10 23 mol −1 (reciprocal moles). [3] [4] It defines the number of constituent particles in one mole, where the particles in question can be either molecules, atoms, ions, ion pairs, or any other elementary entities.
Lanthanum(III) bromide (LaBr 3) is an inorganic halide salt of lanthanum. When pure, it is a colorless white powder. The single crystals of LaBr 3 are hexagonal crystals with melting point of 783 °C. It is highly hygroscopic and water-soluble. There are several hydrates, La 3 Br·x H 2 O, of the salt also known. It is often used as a source of ...