Brucite Mg

Magnesium oxide. The natural minerals, i.e., magnesite (MgCO ), brucite [Mg(OH)9], etc., after being crushed to predetermined size, are calcined at temperatures varying from 1055 to 2000 K, depending upon whether a caustic or a dead-burned produc t (periclase) is being... 

Thus brucite (Mg(OH)2) is also commonly found on surfaces under cathodic protection in seawater. Because more hydroxyl ions (higher pH) are required to cause magnesium hydroxide to precipitate, the magnesium is virtually always found in the calcareous deposits associated with calcium and its presence is an indicator of a high interfacial pH and thus either high cathodic current densities or relatively poor seawater refreshment. 

Allmann found that when suitable trivalent ions were introduced during the precipitation of the hydroxides of Mg, Zn, Mn, Fe, Co, and Ni, these were incorporated in the lattice and the structure changed from the brucite (Mg(OH)2) to the pyroaurite ([Mg6Fe2(OH)l6] [CO,- 4H20]) type of structure [68], One of the nickel materials he prepared was an Ni/Al hydroxide. Axmann et al. [69-71] have given the nickel compounds the general formula... 

Magnesium hydroxide Brucite Mg(OH)4 Common flocculated boiler sludge. 

The BW pH level should be above 10.2 to ensure that hydroxyapatite preferentially precipitates. Also, where magnesium is present, the pH level should be above 10.5 so that magnesium hydroxide [brucite, Mg(OH)2] precipitates, rather than the stickier and more adherent magnesium phosphate [Mg3(P04)2]. In any event, where possible, it is... 

Magnesium typically is present as the phosphate [magnesium hydrox-yphosphate, 3Mg3(P04)2Mg(0H)2] or the hydroxide [brucite, Mg(OH)2] in boiler section soft sludges, and in hard deposits as the silicate (serpentine, 2Mg0-2Si022H20). 

In the OH series, two phases were detectable by XRD in the dried precipitate. One was a phase with the pyroaurite structure, carbonate having presumably arisen from atmospheric CO2, and the other brucite, Mg(OH)2, 0 which pyroaurite is closely related structurally. For both the CCP and IP series, the only structure identifiable in the dried precipitate was that of magnesium hydroxy carbonate. X-ray analysis of the calcined precursors showed MgO together with y-Fe203 in the case of the OH series and HT, but -Fe203 with the CCP and IP series. MgFe204 spinel was also detectable in some cases. 

With time, however, the company encountered problems, including caving of the formation into the wellbore and the loss of permeability in zones that had accepted fluid. In June 1987, a number of sidewall cores were taken from the formation (Mehnert et al., 1990). Mineralogic analysis by x-ray diffraction showed that significant amounts of calcite (CaCCb) and brucite [Mg(OH)2], as well as some amorphous matter, had formed from the original dolomite. In some samples, the dolomite was completely consumed and the rock was found to be composed entirely of a mixture of brucite and calcite. 

The structure of the mineral brucite Mg(OH)2 (space group P2>m ) is formed by Mg(OH)g octahedra, which are connected by edges, forming layers parallel to the (001) plane (see Fig. 7). Hydroxyl groups OH lie on the 3-fold axes and each H-atom is equidistant from three oxygen atoms of the next layer, which is not a perfect position for forming hydrogen bonds between layers. 

All obtainable three-dimensional data sets were used to test this methodology. They were the following Aluminium Iron alloy [20], Brucite (Mg(OH)2), CNBA, DMABC, DMACB, Copper Perchlorophthalocyanine, Poly(l-butene) form III, Polyethylene, Silicon surface, Poly (1,4- trans-cyclohexanediyl dimethylene succinate) (T-cds)... 

A formal description of a mineral presents all the physical and chemical properties of the species. In particular, distinctive attributes that might facilitate identification are noted, and usually a chemical analysis of the first or type specimen on which the name was originally bestowed is included. As an example, the complete description of the mineral brucite (Mg(OH)2), as it appears in Dana s System of Mineralogy, is presented as Appendix 3. Note the complexity of this chemically simple species and the range of information available. In the section on Habit (meaning shape or morphology) both acicular and fibrous forms are noted. The fibrous variety, which has the same composition as brucite, is commonly encountered (see Fig. I.ID) and is known by a separate name, nemalite. ... 

This compound is isostructural with brucite (Mg(OH)2) and Cdl2. The unit cell is hexagonal with a = 0.3258 nm and c = 0.4605 nm. The structure consists of sheets of corner-sharing, trigonally distorted Fe(OH)6 octahedra stacked along the [001] direction. The Fe" ions occupy only half the available octahedral interstices and this results in a structure in which each filled layer of sites alternates with an empty layer of sites. The OH radical behaves as a single entity. Amakinite is a rare mineral of the composition (Fe,Mg,Mn)(OH)2, also with brucite structure. Fe(OH)2 is readily oxidized by air and even by water, upon which the colour changes from white to brownish. The structure can be maintained up to a replacement of one tenth Fe" by Fe " (Bernal et al., 1959). 

Oxides Brucite Mg(OFl)2, corundum AI2O3, ruby AI2O3, sapphire AI2O3... 

Fluoride and hydroxide ions are saturated by bondB of total strength 1. This is achieved by two aluminum octahedral bonds, as in hydrar-gillite (Al(OH)t), with the structure shown in Figure 13-17, topaz (AljSiChF ), jmnyite, described below, and many other crystals, and also by three magnesium octahedra in brucite, Mg(OH)t, and other crystals. 

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