Molybdenum physical properties

Molybdenum hexafluoride [7783-77-9] MoF, is a volatile liquid at room temperature. It is very moisture sensitive, hydrolysing immediately upon contact with water to produce HF and molybdenum oxyfluorides. MoF should therefore be handled in a closed system or in a vacuum line located in a chemical hood. The crystals possess a body-centered cubic stmcture that changes to orthorhombic below —96° C (1,2). The known physical properties are Hsted in Table 1. 

Physical Properties. Molybdenum has many unique properties, leading to its importance as a refractory metal (see Refractories). Molybdenum, atomic no. 42, is in Group 6 (VIB) of the Periodic Table between chromium and tungsten vertically and niobium and technetium horizontally. It has a silvery gray appearance. The most stable valence states are +6, +4, and 0 lower, less stable valence states are +5, +3, and +2. 

Steel is essentially iron with a small amount of carbon. Additional elements are present in small quantities. Contaminants such as sulfur and phosphorus are tolerated at varying levels, depending on the use to which the steel is to be put. Since they are present in the raw material from which the steel is made it is not economic to remove them. Alloying elements such as manganese, silicon, nickel, chromium, molybdenum and vanadium are present at specified levels to improve physical properties such as toughness or corrosion resistance. 

The basic corrosion behaviour of stainless steels is dependent upon the type and quantity of alloying. Chromium is the universally present element but nickel, molybdenum, copper, nitrogen, vanadium, tungsten, titanium and niobium are also used for a variety of reasons. However, all elements can affect metallurgy, and thus mechanical and physical properties, so sometimes desirable corrosion resisting aspects may involve acceptance of less than ideal mechanical properties and vice versa. 

Molybdenum, tris(phenylenedithio)-structure, 1,63 Molybdenum alkoxides physical properties, 2,346 synthesis, 2,339 Molybdenum blue liquid-liquid extraction, 1,548 Molybdenum cofactor, 6,657 Molybdenum complexes acrylonitrile, 2,263 alkoxides, 3,1307 alkoxy carbonyl reactions, 2,355 alkyl, 3,1307 alkyl alkoxy reactions, 2,358 alkyl peroxides oxidation catalyses, 6,342 allyl, 3,1306... 

Molybdenum hexafluoride. 3,1412 Molybdenum-iron-sulfur complexes, 4,241 Molybdenum oxide amino acid formation prebiotic systems, 6, 872 Molybdenum storage protein microorganisms, 6, 681 Molybdenum telluride, 3, 1431 Molybdenum tetraalkoxides physical properties, 2, 347 Molybdenum tribromide, 3,1330 Molybdenum trichloride, 3,1330 Molybdenum trifluoride, 3, 1330 Molybdenum trihalides, 3, 1330 bond lengths, 3, 1330 magnetic moments, 3,1330 preparation, 3,1330 properties, 3, 1330 structure, 3,1330 Molybdenum triiodide, 3,1330 Molybdenum trioxide complexes, 3, 1379 Molybdenum triselenide, 3, 143)... 

The situation is very similar in the Chevrel phases. These are ternary molybdenum chalcogenides A,.[Mo6Xg] (A = metal, X = S, Se) that have attracted much attention because of their physical properties, especially as superconductors. The parent compound is PbMo6Sg it contains Mo6Sg clusters that are linked with each other in such a way that the free coordination sites of one cluster are occupied by sulfur atoms of adjacent clusters (Fig. 13.9). The electric properties of Chevrel phases depend on the number of valence electrons. With 24 electrons per cluster (one electron pair for each edge of the... 

Rhenium is one of the transition elements, which range from metals to metal-like elements. Its chemical and physical properties are similar to those of technetium, which is above it in the periodic table. It is not very reactive. When small amounts are added to molybdenum, it forms a unique type of semiconducting metal. It is also noncorrosive in seawater. 

Elemental composition Mo 59.94%, S 40.06%. The compound or mineral molybdenite may be identified nondestructively by x-ray and from physical properties. Molybdenum content of the material may be determined by various instrumental techniques after digestion of the solid in concentrated HNO3 or aqua regia followed by appropriate dilution of acid extract (See Molybdenum.)... 

Elemental composition Mo 45.70%, F 54.30%. The compound may be identified from its physical properties. Molybdenum may be analyzed by AA or ICP in an acid extract of the compound following digestion with nitric acid. 

Elemental composition Mo 35.12%, Cl 64.88%. Molybdenum pentachloride may be identified from its physical properties and the products it forms in various reactions. The molybdenum content may be measured by flame or fur-nace-AA or ICP/AES measurement following digestion with nitric acid and appropriate dilution. 

Adams, St., Ehses, K.-H., and Spilker, J. (1993). Proton ordering in Peierls-distorted hydrogen molybdenum bronze Hq.ssMoOs Structure and physical properties. Acta Cryst. B49, 958-67. 

These complexes are generally prepared by methods similar to those employed for the dinitrosyl compounds, treatment of a low-valent molybdenum compound with NO or a nitrosyl derivative being the principal method. Compounds and major physical properties are collected in Table 3. 

Mo4 clusters have been identified in many solid phases of molybdenum chalcogenides including PbMo6S8,278 MoSX (X - Cl, Br,I)2 and GaMo4(YY ) (Y, Y - S, Se, Te)-290 the physical properties of these systems are of particular significance. Tetrahedral arrays of... 

For a comparison of the physical properties of tantalum, tungsten, molybdenum, platinum, oopper and nickel, see Balke, Chem. Met. Mng., 1922, 27, 1273. 

Other physical properties of molybdenum are given under Chemical Elements. See also summary of properties of refractory metals under Niobium. 

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