Group 2 metals index

Several platinum compounds, including trimethylplatinum derivatives, are explosively unstable. Some compounds of the other platinum group metals are also of limited stability. Individually indexed compounds are Amminedecahydroxydiplatinum, 4588 Amminepentahydroxyplatinum, 4566 Ammonium hexachloroplatinate, 4180 Ammonium tetranitroplatinate(II), 4573 Diacetatoplatinum(II) nitrate, 1507 Diamminedichloroamidotrichloroplatinum(IV), 4173... 

International Platinum Group Metals Association. Iridium. http //www. ipa news.com/pgm/iridium/index.htm (accessed February 9, 2010). 

In particular, we have reviewed here how aromaticity can account for the electronic structure of ring-like molecules made of both main group metals and metalloids and transition metals. Of the many ways and indexes to characterize aromaticity, a loosely defined concept in itself, we have demonstrated that the very first of them, namely the analysis of the valence molecular orbitals complanented with the Aufbau principle and the Hund s rule for their occupation, and the Hiickel electron counting rules, yields a very appealing, albeit approximate, picture to assess the aromaticity of any particular ring-like molecule. 

Some examples of metal ion indicators. Numerous compounds have been proposed for use as pM indicators a selected few of these will be described. Where applicable, Colour Index (C.I.) references are given.12 It has been pointed out by West,11 that apart from a few miscellaneous compounds, the important visual metallochromic indicators fall into three main groups (a) hydroxyazo compounds (b) phenolic compounds and hydroxy-substituted triphenylmethane compounds (c) compounds containing an aminomethyldicarboxymethyl group many of these are also triphenylmethane compounds. 

The task of predicting a reasonable structure for this alloy was carried out with no information about the powder X-ray diffraction pattern except that one group of investigators had said that it could not be indexed by any Bravais lattice. The prediction of the structure was made entirely on the basis of knowledge of the effective radii of metal atoms and the principles determining the structure of metals and intermetallic compounds. 

Prior to solving the structure for SSZ-31, the catalytic conversion of hydrocarbons provided information about the pore structure such as the constraint index that was determined to be between 0.9 and 1.0 (45, 46). Additionally, the conversion of m-xylene over SSZ-31 resulted in a para/ortho selectivity of <1 consistent with a ID channel-type zeolite (47). The acidic NCL-1 has also been found to catalyze the Fries rearrangement of phenyl acetate (48). The nature of the acid sites has recently been evaluated using pyridine and ammonia adsorption (49). Both Br0nsted and Lewis acid sites are observed where Fourier transform-infrared (FT IR) spectra show the hydroxyl groups associated with the Brpnsted acid sites are at 3628 and 3598 cm-1. The SSZ-31 structure has also been modified with platinum metal and found to be a good reforming catalyst. 

The name adopted for this group of highly reactive (and in some circumstances intramolecularly self-reactive) compounds is intended to cover both arylmetal halides (halogen bonded to the metal) and haloaryl metals (halogen attached to the aryl nucleus). Individually indexed compounds are ... 

Several members of this (often endothermic) group of compounds which contain heavy metals tend to explosive instability, and most are capable of violent oxidation under appropriate circumstances. Fusion of mixtures of metal cyanides with metal chlorates, perchlorates, nitrates or nitrites causes a violent explosion [1], Addition of one solid component (even as a residue in small amount) to another molten component is also highly dangerous [2], Individually indexed compounds are ... 

This group contains many powerful oxidants, the most common being sodium peroxide. Undoubtedly one of the most hazardous is potassium dioxide or superoxide, readily formed on exposure of the metal to air (but as the monovalent O2 ion it is not a true peroxide). Many transition metal peroxides are dangerously explosive. Individually indexed peroxides are ... 

This group contains compounds with azide groups linked to non-oxygenated non-metals, individually indexed compounds being ... 

Of the 3 possible types of peroxy carbonate esters-dialkyl monoperoxy carbonates, dialkyl diperoxycarbonates and dialkyl peroxydicarbonates-, the latter are by far the least stable group. Several of the 16 alkyl and substituted-alkyl esters prepared decomposed violently or explosively at temperatures only slightly above the temperature of preparation (0-10°C), owing to self-accelerating exothermic decomposition. Several were also explosive on exposure to heat, friction or shock [1], Amines and certain metals cause accelerated decomposition of dialkyl peroxydicarbonates by a true catalytic mechanism [2], Individually indexed compounds are ... 

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