Molybdenum disulfide MoS

T. J. Risdon, Properties of Molybdenum Disulfide, MoS (IMolybdenite) Bulletin C-5c, Climax Molybdenum Co., Ann Arbor, Mich., Aug. 1989. 

Molybdenum disulfide Mo-i2Na404qSi XH2O Sodium silicomolybdate... 

MOLYBDENUM DISULFIDE. MoS,. In labora-t(Hy tests, molybdenum disulfide accelerated corrosion of aluminum alloys in the presence of a conductive electrolyte. See also Ref (3) p. 82. 

The most important compound of Mo (TV) is molybdenum disulfide [1317-33-5] M0S2 (21). The layered stmcture of M0S2 is reflected in the flat plate-like hexagonal gray-black crystaUites found in natural and synthetic samples. The stmcture consists of pairs of close-packed layers of sulfur which are echpsed with respect to each other. The close-packed sulfur surfaces are naturally hydrophobic, which faciUtates the extraction of M0S2 ore by flotation. 

Catalysts based on molybdenum disulfide, M0S2, and cobalt or nickel as promoters are used for the hydrodesulfurization (HDS) and hydrodenitrogenadon (HDN) of heavy oil fractions [48,49]. The catalyst, containing at least five elements (Mo, S, Co or Ni, as well as O and A1 or Si of the support), is rather complex and represents a real challenge for the spectroscopist. Nevertheless, owing largely to research in the last twenty years, the sulfided C0-M0/AI2O3 system is one of the few industrial catalysts for which we know the structure in almost atomic detail [49, 50],... 

In addition to the dioxide MoO and the disulfide. MoS . example of leLravalem molybdenum compounds include the tetrachloride. MoClj. and teurabromide. MoBr. both of which are hydrolyzed in hot l-l-O. Other tetravalent compounds include a few of the complexes. 

Of the rather limited number of tetravalent molybdenum and tungsten derivatives known, wre shall mention here only molybdenum disulfide (M0S2), which occurs as the ore molybdenite and the octacyano complexes Mo(CN)i 4 and W(CN) 4 which, along with their pentavalent counterparts (p. 333), represent two of the very few examples of octa-covalency. 

Figure III. X-ray dififraction patterns for molybdenum disulfide (h, k, 1) generated from Mo(VI) precursors reacted at coal liquefaction conditions.

There are seven known isotopes of molybdenum that occur naturally Mo, " Mo, Mo, Mo, Mo, Mo, and °°Mo. Their natural abundances range from 9.25 percent ( Mo) to 24.13 percent ( Mo). Common compounds of molybdenum include molybdenum disulfide (M0S2), molybdenum trioxide (M0O3), molybdic acid (H2M0O4), molybdenum hexafluoride (MoFg), and molybdenum phosphide (M0P2). 

Molybdenum disulfide, M0S2, can be prepared by chemical vapor deposition using M0CI5 [116, 117], MoFf, [117] or Mo(CO)6 (9) [118] as the molybdenum source. The sulfur source in each case is hydrogen sulfide. The molybdenum tetrakis(thiolate) compound, Mo(S-f-Bu)4, is a unimolecular precursor to M0S2 and decomposes at temperatures as low as 100°C [111]. 

Molybdenum, Mo Molybdenum disulfide / extreme pressure additive <20 to 3000 /ig/g... 

MoS, molybdenum disulfide MSWI municipal solid waste incineration... 

ABS Acrylonitrile-butadiene-styrene HOPE High-density polyethylene LDPE Low-density polyethylene MoS Molybdenum disulfide PA Polyamide(s) PAI Polyamide-imide PBT Polybutylene terephthalate PEEK Polyether ether ketone PEI Polyether imide PET Polyethylene terephthalate PI Polyimide PMMA Polymethylmethacrylate POM Polyoxymethylene PP Polypropylene PPS Polyphenylenesulfide PSU Polysulfone PTEE Polytetrafluoroethylene PU Polyurethane PVDE Polyvinylidine fluoride UHMWPE Ultra-high molecular weight polyethylene UV Ultraviolet XPE Crosslinked polyethylene Source Author s own files ... 

MoS is a black powder insoluble in most solvents. It crystallizes like graphite with hexagonal layer molecules MoSj infinitely extended in two dimensions (Figure 25.4). Within the layer the sulfur atoms are effectively close packed and the molybdenum atoms are situated in the octahedral holes. The layers are bound to each other by very weak van der Waals forces. Because of this the layers slip easily against each other and the sulfide has lubricant properties. It is an essential component in solid lubricants that can be used at much higher temperatures than conventional lubricants. They lubricate up to 350°C in air and 1200°C in vacuum or in an inert atmosphere. Molybdenum disulfide lubricants can also be suspended in special oils and used as lubricating aerosol sprays. 

Lithium molybdenum disulfide (Li/MoSj) Li Mo 2 LiAsFe, PC/EC Polypropylene xLi + M0S2 LLM0S2... 

---