Metal halites

The most frequently encountered reaction on heating metal chlorites is disproportionation 

Ba(Br02)2 is formed [886] during decomposition of the bromate in oxygen at 523 K. 

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Other metal bromates and iodates Metal halites... 

The preferred slip plane in ionic crystals with the halite (NaCl) structure, such as NaCl or LiF, is 110, and the slip direction used is (110). This slip system is sketched in Figure 10.17. For the more metallic halite structure solids such as titanium carbide (TiC), the slip system is similar to that in face-centred cubic metals, 1 1 1 (110). 

Other oxoacid salts of the alkali metals are discussed in later chapters, e.g. borates (p. 205), silicates (p. 347), phosphites and phosphates (p. 510), sulfites, hydrogensulfates, thiosulfates, etc. (p. 706) selenites, selenates, tellurites and tellurates (p. 781), hypohalites, halites, halates and perhalates (p. 853), etc. 

D and 5 0 data on fluid inclusions and minerals, 8 C of carbonates, salinity of inclusion fluids together with the kind of host rocks indicate that the interaction of meteoric water and evolved seawater with volcanic and sedimentary rocks are important causes for the formation of ore fluids responsible for the base-metal vein-type deposits. High salinity-hydrothermal solution tends to leach hard cations (base metals, Fe, Mn) from the country rocks. Boiling may be also the cause of high salinity of base-metal ore fluids. However, this alone cannot cause very high salinity. Probably the other processes such as ion filtration by clay minerals and dissolution of halite have to be considered, but no detailed studies on these processes have been carried out. 

Metal- and halogen-containing complexes (metal fulminates, halites, halates, etc.). 

Many simple minerals, especially simple salts like halite, NaCl, sulfides, sulfosalts and oxides, have structures based upon cubic or hexagonal closest-packed arrays of either cations or anions. Coordination geometries of metal ions in many of these kinds of minerals are thus confined to more or less regular octahedra and tetrahedra. The occupancy of the two types of sites is dictated by the stoichiometry of the mineral, the radius of the ions involved and their preferred coordination geometries. Coordination of cations in mineral species in terms of bonding and crystal field effects has been extensively reviewed.16-21 Comprehensive lists of ionic radii relevant to cation coordination geometries in minerals have also been compiled.16,21... 

Halite (NaCl) can be selectively floated using n-alkyl carboxylates (collector), heavy metal ions (activator), and a non polar oil (additional collector). This yields a concentrated dispersion of the potash. Alternatively, the potash can be selectively floated from a saturated brine solution, using n-alkyl amine as the collectors, leaving the other salts behind. The flotation steps may involve a sequence of rougher, cleaner, and re-deaner stages. Either way the collected potash would be centrifuge de watered, dried, then sized by screening. The final potassium concentrate would probably be at least about 60%,... 

The chemical category of inorganic salts encompasses many substances that dissociate completely in water, but only one salt, sodium chloride, is referred to by the common name, salt. Sodium chloride is ubiquitous in both its occurrence and its many uses. To date, there are over 14,000 uses for salt.1 Salt is used as a feedstock for many chemicals including chlorine, caustic soda (sodium hydroxide), synthetic soda ash (sodium carbonate), sodium chlorate, sodium sulfate, and metallic sodium. By indirect methods, sodium chloride is also used to produce hydrochloric acid and many other sodium salts. In its natural mineral form, salt may take on some color from some of the trace elements and other salts present, however, pure sodium chloride is a white to colorless crystalline substance, fairly soluble in water.2 Also known as halite, the substance... 

The misfit layer compounds are typified by materials with a formula MS +fiTS2)m, in which T is a transition metal atom, Ti, V, Cr, Nb, or Ta, and M is a large atom such as Sn, Pb, Bi, with stereochemically active electron lone pairs, or a lanthanide. The structures are built from S-T-S layers, in which the metal T takes trigonal-prismatic coordination. These layers are interleaved with layers of the halite structure, usually two or three atom layers in thickness, with composition MSx. This leads to a chemical formula of [MSx]n(71S 2)m, where n varies from approximately 1.08-1.24, and m takes values of 1-3, depending upon the nature of T and M. A typical example is the compound [(Lni/3Sr2/3S)i.5]i.i5 NbS2. In all of the misfit layer compounds, the lattice parameter of the interpolated halite layers fit one lattice parameter of the rS2 layer but not the other, so that in this direction, the... 

Should the anions adopt hexagonal close-packing and all of the octahedral sites contain a cation, the hexagonal analogue of the halite structure is produced. In this case, the formula of the crystal is again MX. The structure is the nicolite, (NiAs), structure, and is adopted by a number of alloys and metallic sulphides, including NiAs, CoS, VS, FeS and TiS. 

The method can be illustrated by reference to a classical study of the defects present in iron monoxide1. Iron monoxide, often known by its mineral name of wiistite, has the halite (NaCl) structure. In the normal halite structure, there are four metal and four non-metal atoms in the unit cell, and compounds with this structure have an ideal composition MX 0, (see Chapter 1, Section 1.8). Wiistite has an oxygen-rich composition compared to the ideal formula of FeOi.o- Data for an actual sample found an oxygen iron ratio of 1.059, a density of 5728 kg m 3, and a cubic lattice parameter, a, of 0.4301 nm. Because there is more oxygen present than iron, the real composition can be obtained by assuming either that there are extra oxygen atoms in the unit cell, as interstitials, or that there are iron vacancies present. 

Model A Assume that the iron atoms in the crystal are in a perfect array, identical to the metal atoms in the halite structure and an excess of oxygen is due to interstitial oxygen atoms over and above those on the normal anion positions. The ideal unit cell of the structure contains 4 Fe and 4 O, and so, in this model, the unit cell must contain 4 atoms of Fe and 4(1+x) atoms of oxygen. The unit cell contents are Fc404+4a and the composition is FeOi.059-... 

Model B Assume that the oxygen array is perfect and identical to the non-metal atom array in the halite structure and that the unit cell contains some vacancies on the iron positions. In this case, one unit cell will contain 4 atoms of oxygen and (4-4x) atoms of iron. The unit cell contents are Fc4 4a04 and the composition is Fei/i.058O1.0 or Feo.9440. 

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