Approximate Breakdown of Molybdenum Utilisation

Molybdenum trioxide, or molybdic oxide , melts at 795 C and boils at 1155°C at normal atmospheric pressure. It has a fairly high hardness and in many early publications was described as a harmful abrasive product from the oxidation of molybdenum disulphide in service. In fact the trioxide is not highly abrasive, being possibly less abrasive in some circumstances than molybdenum disulphide itself , and it has been recommended for use as a lubricant at elevated temperatures to 700°C. 

Molybdenum dioxide, although generally less Important than the trioxide, is more abrasive . It has been suggested that abrasion associated with synthetic or 

The only important sulphide of molybdenum is the disulphide MoSj, whose properties are described in the next chapter. Apart from the disulphide, three other sulphides have been reported , and some of their salient properties are listed in Table 3.4. 

The sesquisulphide Mo Sj is said to have been prepared by rapid heating of the disulphide in the absence of air, and extraction with cold dilute aqua regia, or by combination of molybdenum and sulphur at 1300°C °. 

The pentasulphide MojSg is said to be formed as a dark brown amorphous precipitate of the trihydrate when hydrogen sulphide is passed through an aqueous solution of a pentavalent molybdenum coompound, but like all pentavalent molybdenum compounds it is unstable. 

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