Chlorites classification

As a result of chemical, optical, thermal, and X-ray studies of chromium-bearing chlorites, Lapham suggested a definitive classification based on the structural location of Cr. He showed that for Cr203 contents under 2%, there is no noticeable effect of Cr on the structure. He suggested using the accepted Mg-Fe chlorite classification with a Cr prefix for these specimens, for example, Cr-clinochlore or Cr-penninite. For CrjOj contents greater than 2 %, there are appreciable effects on the optical, thermal, and X-ray properties. These effects differ, depending on whether the Cr is present in tetrahedral or octahedral coordination. Lapham recommends use of the name kammererite for specimens with octahedral Cr, and the name kotschubeite for those with tetrahedral Cr. 

Hypochlorites, chlorites, chlorates and perchlorates all represent the same dangers, which are linked to the fact that they are strong oxidants. The danger is not directly linked to the importance of the oxidation state of chlorine atom and this is partly for kinetic reasons. The main factors of the accidents described in the technical literature are not the intrinsic properties of each anion, but rather the frequency with which they are used. So chlorates and perchlorates are more often involved in accidents than hypochlorites and especially chlorites, which are hardly used. Thus the classification below does not provide positive indications about the dangerous properties of each substance mention. ... 

Microlithofacial classification of the sandstones is based on Dott s classification modified by Pettijohn et al. (1972). They are mostly arenites and subarkose and quartz wackes (rare sublithic, sporadically lithic and arkosic). Quartz is the main component of the sandstones (about 60-70 vol. percent). Feldspars (6 vol. percent) are mostly represented by potassium feldspars with plagioclases in lesser amounts. Some micas (muscovite and biotite) and chlorites are observed. Mica content of arenites reaches 3 vol. %, but is higher in the wackes. Heavy minerals present include zircon, sphene, rutile and apatite. Magmatic rocks (volcanic more than Plutonic) are predominant among lithoclasts (about 2 vol. %), but some metamorphic and sedimentary clasts being present too. 

The chemistry of the chlorites has been reviewed by Hey (1954), Foster (1962) and Deer et al. (1962). Hey and Foster have presented classification schemes. All chlorites have replacement of Si by Al which affords the tetrahedral sheets a net negative charge. This charge is balanced by the substitution of Al and Fe3+ for Mg and Fe2+ in the two octahedral sheets. 

Fig. 17. Classification of chlorites based on the two principal types of ionic replacement. (After Foster, 1962.)...

A classification of the chlorites was devised by Foster (1962) based on ionic replacement of Al by Si in the tetrahedral sheet and Mg by Fe2+ in the octahedral sheet. Fig. 17 shows the classification with the location of 150 chlorites. The dividing lines are arbitrary and imply no genetic significance in fact, they probably have some. 

With this framework of component processes in mind, Orbdn et al.58) proposed the following preliminary classification of chlorite oscillators ... 

DOT CLASSIFICATION 5.1 Label Oxidizer SAFETY PROFILE A strong oxidizer. Ignites on contact with potassium thiocyanate. Reaction with CI2 yields explosive CIO2. When heated to decomposition it emits toxic fumes of CT. See also CHLORITES and CALCIUM COMPOUNDS. 

Foster M. D. (1962) Interpretation of the composition and a classification of chlorites. US Geol. Surv. Prof. Pap. 414A, 33. 

Geologically and genetically, clay minerals are difficult to define simply and adequately, but broadly they are layer lattice silicates of secondary origin. In the same classification are the micas, talc, chlorites, and serpentines which are not strictly clay minerals. In this context, secondary origin means that mineral formation has arisen from the weathering of primary or igneous rock, e.g. granites and basalts. 

Briggs-Rauscher) and bromate oscillators (Belousov-Zhabotinskii), these new reactions are chlorite oscillators. For the chlorite oscillators, Orban et al. (1982-3) have also given a preliminary classification. 

IIIL) Orban, M., Dateo, C., De Kepper, P., Epstein, I. R. Systematic Design of Chemical 1982-3 Oscillators, Part 11. Chlorite Oscillators New Experimental Examples. Tristability and Preliminary Classification. J. Am. Chem. Soc. 104, 5911-5918 (IIIL) Orban, M., De Kepper, P., Epstein, I. R., Kustin, K. Systematic Design of Chemical... 

In Ihe early literature dealing with soil acidity, soils were characterized by their percent base saturation at specified pH levels. Soils with low percent base saturation values were considered to be dominated by kaolinite and hydrous oxide minerals, but soils of high percent base saturation were considered to be dominated by 2 1-type minerals, such as montmorillonite, vermiculite, chlorite, and the micas. Base saturation is a criterion of soil taxonomy in the U.S. soil classification scheme. Fifty percent base saturation (based on soil CEC at pH 7) is one criterion for distinguishing between mollic epipedons (dark, high organic horizons) and their umbric (low organic) counterparts. 

Classification Chlorite salt Empirical CINa02 Formula NaCI02... 

Sodium Chiorite Soi n. 50, Tech.] Sodium Chiorite, Tech.. See Sodium chlorite Sodium N-chlorobenzenesulfonamide Sodium, (N-chlorobenzenesulfonamido)-. See Chloramine-B Sodium p-chloro-m-cresol CAS 15733-22-9 EINECS/ELINCS 239-825-8 Synonyms p-Chloro-m-cresol, sodium salt 3-Methyl-4-chlorophenol, sodium salt Sodium p-chloro-m-cresolate Sodium p-chloro-m-methylphenate Sodium 4-chloro-3-methylphenolate Classification Org. compd. 

Orban, M. Dateo, C. De Kepper, P. Epstein, I. R. 1982a. Chlorite Oscillators New Experimental Examples, Tristability and Preliminary Classification, J. Am. Chem. Soc. 104, 5911-5918. 

By studying appropriately perturbed autocatalytic reactions in a flow reactor (cSTR), we have produced a family of some 20 new oscillators containing chlorite ion. In addition, several new bromate oscillators (e.g., BrOs -Mn -Br " and BrOs - ), which are simpler in composition and mechanism than the classic Belous ov-Zhabotinskii system, have been discovered. Mechanistic considerations have given rise to a tentative classification of oxyhalogen based oscillators which shows the linkage and differences between the various classes. 

A major step toward understanding the bromate oscillators was the formulation by Noyes ([ 32]) of a mechanistically based classification scheme for the known (batch) bromate oscillators. Since that time, a variety of additional oxyhalogen (bromate, chlorite, iodide) systems have been shown to oscillate in the... 

M. Orban, C. Dateo, P. De Kepper, and I. R. Epstein, Systematic design of chemical oscillators. 11. Chlorite osdllators new experimental examples, tristability, and preliminary classification, Journal of the American Chemical Society, vol. 104, no. 22, pp. 5911-5918, 1982. 

Specific lithological classification permits placing constraints on the final petrophysical solution. In the case of feldspathic sand, for example, one might wish to predict the presence of illite/smectite, chlorite and kaolinite based on various feldspar decomposition models. Similarly, it might be predicted that calcic dolomite, one of the specific lithologies for carbonate, is composed mainly of dolomite with small amounts of calcite and possibly anhydrite (Pemper et al., 2006). 

Figure 4. Classification of (a) orthochlorites and (b) the oxidised chlorites (after Hey [1954]).

It is difficult to achieve a comprehensive classification scheme for chlorites because of the variety of chemical substitutions that are possible. Furthermore, classifications are subject to change with advances in our knowledge of the compositions, properties, and structures of chlorites. A summary of the main classification schemes follows. These refer primarily to trioctahedral Mg-Fe chlorites. The classifications are grouped into three categories (1) those of historical interest prior to 1920, (2) those in the period 1920 to 1940, and (3) modern classifications in which the crystal structure and the unit-cell contents are utilized. Aside from the names mentioned in connection with the different classifications, no effort will be made in this section to list the large number of species names that have been proposed for chlorites of different compositions and physical properties. 

The most comprehensive of the early classifications was that of Tschermak, who subdivided chlorites into a primary series of orthochlorites and a secondary series of lepto-chlorites. Most chlorites could be classed as orthochlorites, and their compositions could be explained as mixtures of different proportions of two end-member molecules serpentine (Sp = Si2Mg3H409) and amesite (At = SiAl2Mg2H409). This series was further subdivided into six parts, as indicated in Table 1. 

On the basis of new chemical analyses of chlorites, Orcel showed that previous classifications were not suitable. He proposed an empirical classification based on the ratios of the oxides present. He defined the following general and specific ratios ... 

These authors revised Orcel s earlier classification in the light of the known crystal structure of chlorite. They exclude antigorite, cronstedtite, and berthierine (sometimes called... 

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