Tungsten, Vanadium, and Chromium

For vanadium and chromium the first ionization energies are much lower than the first ionization energies of phosphorus and sulphur, respectively. This explains the high heats of formation of VC13 and CrCl3. In uranium, the tetravalent state is more stable than that in tungsten because uranium as an actinide has a different electron configuration. 

Vanadium and chromium have been shown to be essential by nutritional studies. Of the remaining metals, it appears possible that tin and tungsten may be essential. The biological properties of the essential metalloids such as selenium1035 and arsenic1060 will not be considered. 

A.P.G. Gervasio, G.C. Luca, A.A. Menegario, B.F. Reis, H. Bergamin-Filho, On-line electrolytic dissolution of alloys in flow injection analysis. Determination of iron, tungsten, molybdenum, vanadium and chromium in tool steels by inductively coupled plasma atomic emission spectrometry, Anal. Chim. Acta 405 (2000) 213. 

Chromium, tungsten, vanadium and molybdenum plumbites 360-400 Toluene Benzaldehyde Benzoic acid (54)... 

Figure 12.22 In the fourth period, vanadium and chromium have very similar melting points. Molybdenum and tungsten have the highest melting points in the fifth and sixth periods, respectively. All of these elements are located near the middle of the period where the bonding orbitals are mostly filled and the antibonding orbitals mostly empty.

Some of the most commonly used metals deposited by sputtering are aluminum, copper, chromium, gold, molybdenum, nickel, platinum, silver, tantalum, titanium, tungsten, vanadium, and zirconium. 

For the polymerization of cyclobutene, Natta and coworkers [37] reported binary catalytic systems containing titanium, vanadium, chromium, and tungsten to be the most active, those of molybdenum less active, and systems derived from cobalt, iron, manganese, and uranium totally inactive. Catalysts based on vanadium and chromium yield preferentially polycyclobutylene by addition polymerization, those with molybdenum and tungsten give polybutenamer by ring-opening... 

The preferred catalyst for the Katasulf process was composed of two metals—one (e.g., iron, nickel or copper) combined with the hydrogen sulfide to form metal sulfide, and the other (e.g., tungsten, vanadium, or chromium) served as an oxygen carrier. 

Ahquat 336 Henkel vanadium, possibly chromium, tungsten, and uranium... 

The elements that decrease the extent of the austenite field include chromium, siUcon, molybdenum, tungsten, vanadium, tin, niobium, phosphoms, aluminum, and titanium. These are known as ferrite stabilizers. 

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