Ruthenium atomic weight

Atomic Weight.—Approximate Atomic Weight.—That the atomic weight of ruthenium is approximately 100 and not a multiple or submultiple of this amount is evident from various considerations, namely ... 

Its specific heat is 0-0611. Assuming a mean atomic heat of 0-1, the atomic weight of ruthenium, according to Dulong and Petit s Law, is approximately 105. 

The most appropriate position for ruthenium in the Periodic Table is as the first member of the second series of horizontal triads. Hence its atomic weight should lie between that of molybdenum (96) and rhodium (102-9), but nearer in point of magnitude to the last named since an element should be in Group VII between it and molybdenum, but has yet to be discovered. 

The alkali chlor-ruthenates are isomorphous with the chlor-platinates, and therefore, by the application of llitscherlich s Law, they must be assumed to contain, like the platinum derivatives, one atom of ruthenium, their generic formula being M,RuC16. Similarly, ruthenium dioxide is isomorphous with cassiterite, SnO,. and with rutile, TiCL. from which it may be concluded that its formula is RuO.,. Analyses of these compounds indicate that the atomic weight of ruthenium is 101-7. 

According to the Periodic Classification, rhodium, which in its properties forms a mean between cobalt and iridium, and betw een ruthenium and palladium, should have an atomic weight intermediate between the values for these extreme elements, namely, from 102 to 105. 

The Grouping of Elements into Triads—Atomic Weights of the Elements— General Properties of tho Elements—Comparative Study of Iron, Cobalt, and Nickel—Their Position in tho Periodic Table—Comparative Study of Iron, Ruthenium, and Osmium—Comparative Study of Cobalt, Rhodium, and Iridium—Comparative Study of Nickel, Palladium, and Platinum. 

However, its bine chloride solntion had been previously observed by Vauquehn in Paris in 1804. Rnthenium is the least abundant platinum metal (10 to 10 ppm) after rhodium. In 2002, the demand for ruthenium was 11.6 tons, an increase of 1.8 tons compared to 2001, mainly becanse of increased sales of rnthenium paste to the electronics industry, for the manufacture of chip resistors and hybrid integrated circuits (HIC). Its atomic number is 44, its atomic weight 101.07, and its electronic configuration [Kr]4d 5s. Seven stable isotopes are known. Some physical data are reported in Table 1 (see Coordination Chemistry History mA Coordination Numbers Geometries). 

Triplet-triplet energy transfer was also proposed for the quenching of the triplet donors benzil and Ru (bipy) by d metallocenes of iron, ruthenium, osmium, and cobalt (210). The quenching efficiencies did not correlate with the atomic weight of the central metal but instead with the energy of the longest wavelength absorption band of the metallocene. 

In 1869 Mendeleev 1 predicted the existence of an clement of atomic weight ]()() occupying the vacant space between molybdenum and ruthenium in his Periodic System. He named this element provisionally ekamanganese" corresponding to its position below manganese. In 1913 and 1914 Moseley 2,3] found the atomic number of elements in the Periodic System to be directly proportional to the square root of the frequency of their K ox L X-ray emission and thus derived a vacant space for the atomic number 43 in addition to 61 (Pm) and 75(Re). These indications of Mendeleev and Moseley stimulated numerous attempts to demonstrate the occurrence of element 43 [4..S] and the other elements lacking in nature. 

Such are nickel and cobalt, whose atomic weights are very close to each other, ihodium, ruthenium and palladium on the rate hand, iridium, osmium and platinum on the other ate also elements which closely resemble one another, and which have very similar atomic weights. Iron and manganese have similar properties and their atomic weights are also very similar ... 

English chemist Humphry Davy discovers the elements barium and calcium. French chemist Joseph-Louis Gay-Lussac proposes Gay-Lussac s law gases combine among themselves in very simple proportions. English chemist John Dalton publishes A New System of Chemical Philosophy, in which he formulates the atomic weight theory. Davy, Gay-Lussac, and French chemist Louis-Jacques Thenard isolate the element boron. Polish chemist Jedrzej Sniadecki discovers the element ruthenium. 

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