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  Home >> Inorganic Chemistry Dictionary >> Mond process Monotropy

Molybdenum sesquioxide
MoO3, water-insoluble, gray-black powder with slight solubility in acids; used as a catalyst and as a coating for metal articles.

Molybdenum trioxide
MoO3, a white solid at room temperature, with a melting point of 795°C; soluble in concentrated mixtures of nitric and sulfuric acids and nitric and hydrochloric acids; used as a corrosion inhibitor, in enamels and ceramic glazes in medicine and agriculture, and as a catalyst in the petroleum industry.

Molybdic acid
any acid derived from molybdenum trioxide, especially the simplest acid H2MoO4, obtained as white crystals.

Mond process
a metallurgical process used in the extraction of nickel by the action of carbon monoxide CO, on the impure metal. This gives nickel carbonyl Ni(CO)4, a gas that decomposes at 200°C to give pure nickel and carbon monoxide

Monel metal
refers to an alloy of nickel (60-70%), copper (25-35%), and small quantities of iron, manganese, silicon, and carbon. It is used to make acid-resisting equipment in the chemical industry.

Monobasic sodium phosphate
NaH2PO4, white crystals that are slightly hygroscopic, soluble in water, insoluble in alcohol; used in baking powders and acid cleansers, and as a cattle – food supplement.

Monodentate ligand
a ligand that can attach itself to a metal ion by only one atom.

Monohydrate
a salt that has a single molecule of water of crystallization, such as sodium carbonate monohydrate, Na2CO3.H2O.

Monotropy
refers to the existence of a single allotrope of an element that is always more stable than the other(s) regardless of temperature; phosphorus, for example, exhibits monotropy. The phase diagram for a monotropic element reveals that one allotrope always has a lower vapour pressure than the other(s) at all temperatures; this has been the stable allotrope.

Mordant
a substance used in certain dyeing processes. Mordants are often inorganic oxides or salts, which are absorbed on the fabric. The dyestuff then forms a coloured complex with the mordant, the colour depending on the mordant used as well as the dyestuff.

Mosaeley’s law
lines in the X-ray spectra of elements have frequencies that depend on the proton number of the element. For a set of elements, a graph of the square root of the frequency of X-ray emission against proton number is a straight line (for spectral, lines corresponding to the same transition).

Mother liquor
the solution left after the formation of crystals.

Multiple bonding
bonding between atoms in which there is overlap of orbitals in more than one position in space. The electrons may come equally from each atom or be derived from only one of the atoms (co-ordinate bond, back bonding). Generally the primary bond is a  s-bond with extra interaction p-or s bonding.

Multiplicity
a measure of the number of lines in a fine structure.

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