Group 6 molybdenum and tungsten

The diagram above represents part of an extended structure. The terminal Cl atoms are shared between units 6 are shared between 2 units, and 3 are shared between 3 units. 

The answers to these questions can be found by reading the last 

The solid state structure of NbLt consists of edge-shared octahedra. Explain how this description is consistent with the stoichiometry of the compound. 

The formula of Nb3ln can be written as [Nb3l8]l6/2- Explain how this can be translated into a description of the solid state structure of the compound. 

The metals are inert towards most acids but are rapidly attacked by fused alkalis in the presence of oxidizing agents. 

Molybdenum and tungsten exhibit a range of oxidation states Table 19.3) although simple mononuclear species are not known for all states. The extensive chemistry of Cr(II) and Cr(III) (see Section 21.7) has no counterpart in 

Molybdenum and tungsten compounds are usually iso-morphous and essentially isodimensional. 

The properties of Mo and W are similar. Both have very high melting points and enthalpies of atomization (Table 6.2 and Fig. 22.2). The metals are not attacked in air at 298 K, but react with O2 at high temperatures to give MO3, and are readily oxidized by the halogens (see later). Even at 298 K, oxidation to M(VI) occurs with F2 (eq. 22.27, see Fig. 22.16). Sulfur reacts with Mo or W 

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In Table 3, the heats of formation of these compounds are given, together with those for the carbonyls of two other metals of the chromium group, molybdenum and tungsten. The mean dissociation energies refer to tJie processes,... 

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See also in sourсe #XX -- [ ]

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