Tungsten atomic weight

Lee DC, Halliday AN (1995) Precise determinations of the isotopic compositions and atomic weights of molybdenum, tellurium, tin and tungsten using ICP magnetic-sector multiple collector mass-spectrometry. Int J Mass Spectr Ion Proc 146 35-46... 

There seems little reason to question, therefore, the propriety of placing osmium as the first member of the third series of triads in Group VIII. This postulates an atomic weight intermediate between 184 (at. wt. of tungsten) and 193-1 (at. wt. of iridium), but nearer to the latter value, inasmuch as an intermediate element between tungsten and osmium is missing from Group VII. 

Atomic Weight.— Like chromium and molybdenum, tungsten may in its compounds be di-, tri-, or hexa-valent from a consideration of its specific heat, the isomorphism of its compounds, its position in the... 

The determinations of the atomic weight of tungsten which have been prrblished are appended ... 

In 1872 Mendeleeft pointed out that there was no place in the Periodic Table for a trivalent element of atomic weight 120, and drew attention to the similarity of uranium to chromium, molybdenum, and tungsten he therefore suggested that the atomic weight should be doubled, so that uranium could be placed below these elements in the table. He also formulated the oxides, by analog with those of the other elements in the group, as follows uranous oxide UOg, urano-... 

Occurrence—History—Preparation —Tungsten Pilanieiits—Physical Properties —Spectrum—Chemical Properties—Atomic Weight—Uses—Alloys. 

If the region between helium and uranium contains 91 elements then five are as yet undiscovered. These have been predicted and named (1) eka-manganese with an atomic number 43 and an atomic weight approximately 100 (2) dwi-manganese, atomic number 75 falling between tungsten and osmium (3) eka-iodine, atomic number 85 (4) eka-neodym-ium, a rare earth element of atomic number 61 and (5) eka-caesium of atomic number 87. Of these, greatest interest has... 

Tungsten hexachloride, WClo, is prepared by burning the metal in pure, dry chlorine. If moisture or oxygen is present, the red oxychloride is formed, and this is very difficult to remove. The hexachloride forms dark violet crystals, which when pure are stable in air and cold water. But in the presence of the oxychloride it absorbs moisture from the air and decomposes in cold water. This compound has been used in some of the most accurate determinations of the atomic weight of tungsten. 

Roscoe discovered tungsten pentachloride and pentabromide, uranium pentachloride,2 and niobium trichloride (which he found gave NbOClg and CO when heated in COg). He determined the vapour densities of PbClg and TlCl, showed that Delafontaine s supposed new rare-earth metal philippium is a mixture of yttrium and terbium, and redetermined the atomic weight of carbon (C = 12 002). Roscoe published several papers and a book on spectrum analysis. 

Tungsten has a body-centered cubic lattice with all atoms at the lattice points. The edge length of the unit cell is 316.5 pm. The atomic weight of tungsten is 183.8 amu. Calculate its density. 

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