Compounds double nitrates

Although it might be assumed quite reasonably that the coordination chemistry of the some 15 elements known during Werner s lifetime would have developed significantly during that period, the literature contains only a few accounts of synthesis and characterization. Indeed, the 1920 edition of Werner s classic monograph (50) records essentially the same information as the 1908 edition, namely the compositions of a limited number of double nitrates, sulfates, and oxalates. Both Spencer ( 5) and Little in their comprehensive compilations of data at about the same time, describe only certain lanthanide double salts and adducts, but not within the framework of complex compounds or coordination chemistry. 

Praseodymium is difficult to obtain in pure compounds buffi because of its scarcity and close resemblance to other elements. The best methods of separation are as follows (1) Hot. out from a double magnesium nitrate scries such fractions us contain only lanthanum and praseodymium continue the fractionation of the same salt or of double ammonium nitrate, Praseodymium appears at the soluble end, but usually neodymium appears there also, even if its presence is unsuNficctcd at first. (2) Remove from the magnesium double nitrate series the fractions which contain only praseodymium and neodymium and continue the fractionation as the manganese double nitrate, when praseodymium separates in the least soluble portions, Other methods used are Crystallization of the oxalates from nitric add of the double ammonium nitrate or double carbonate. 

Compounds. — In its chemical relations thorium resembles both zirconium and quadrivalent cerium. It is somewhat more markedly electropositive than either of these elements, acidic properties being entirely absent. Its neutral salts are hydrolyzed somewhat in solution, and consequently are acid to indicators. They are however sufficiently stable to permit recrystallization from water solution. In basicity thorium approaches the elements of the yttrium group. Double salts are less common than with cerium and zirconium, but characteristic double nitrates, R2 Th(N03) 6, crystallize well and are iso-morphous with the analogous ceric double nitrates. Thorium resembles cerium in forming a double potassium sulfate which is insoluble in potassium sulfate solution, hut differs from it in... 

There is considerable evidence for the association of Bi3+ ion with nitrate ions in aqueous solution. The nitrate ions appear to be mainly bidentate, and all members of the set Bi(N03) (H20)3 +. .. Bi(N03)4 appear to occur.70 From acid solution various hydrated crystalline salts such as Bi(N03)3 5H20, Bi2(S04)3 and double nitrates of the type M3[Bi(N03)6]2,24H20 can be obtained. Treatment of Bi203 with nitric acid gives bismuthyl salts such as BiO(N03) and Bi202(0H)(N03). Similar bismuthyl salts are precipitated on dilution of strongly acid solutions of various bismuth compounds. Bismuthyl salts are generally insoluble in water. 

Formula weights Th(N03)4 480.15 Th(N03)4 5HgO 570.23. Very readily soluble in HgO and alcohol. Due to hydrolysis, the aqueous solution becomes acid and slowly precipitates a basic salt. The commercial product usually contains about four moles of HgO it usually also contains some sulfate. Combines very readily with alkali and alkaline earth nitrates to yield double nitrates (very beautiful crystals). The alkali salts corresponding to the formula Alkg[Th(N03)s] ciystallize in anhydrous form, and the corresponding alkaline earth compounds with eight moles of HgO. Water-containing alkali thorates Alk[Th(N03)s] have also been described. 

The volume Rare Earth Elements C 9 deals with the rare earth selenides, oxide selenides, selenites, and selenates, as well as the associated alkali double compounds, diselenate nitrates, and the selenide halides. So far as meaningful and as in all earlier volumes of Rare Earth Elements Series C ( Seltenerdelemente Reihe C), comparative data are presented in sections preceding treatment of the individual compounds and systems. 

If the coordination polyhedron approximates the icosahedron, the crystal-field parameters of rank k = 2 and k = 4 will be small. The parameters with k = 6 will be almost in the icosahedral ratio. By observing that in the rare-earth double nitrates the B /B and B /Bq ratios are close to the icosahedral ratios, Judd (1957) concluded that the coordination polyhedron of these compounds can be considered as a slightly distorted icosahedron. It is remarkable that Judd came to this result, before the structure of the double nitrates was solved by X-ray diffraction. For Eu2Zn3(N03)i2-24H2O (Gorller-Walrand et al. 1992) the B BI and B lBl ratios are 1.492 and -1.097, respectively (fitting in a C3V symmetry). Compare these values to the ratios predicted for the ideal icosahedron 1.527 and -0.921. 

Chemical Properties and Reactivity. LLDPE is a saturated branched hydrocarbon. The most reactive parts of LLDPE molecules are the tertiary CH bonds in branches and the double bonds at chain ends. Although LLDPE is nonreactive with both inorganic and organic acids, it can form sulfo-compounds in concentrated solutions of H2SO4 (>70%) at elevated temperatures and can also be nitrated with concentrated HNO. LLDPE is also stable in alkaline and salt solutions. At room temperature, LLDPE resins are not soluble in any known solvent (except for those fractions with the highest branching contents) at temperatures above 80—100°C, however, the resins can be dissolved in various aromatic, aUphatic, and halogenated hydrocarbons such as xylenes, tetralin, decalin, and chlorobenzenes. 

In addition to reactions with HO, tropospheric organic compounds may be oxidized by ozone (via ozonation of non-aromatic carbon/carbon double bonds, Atkinson 1990) and in some cases by reaction with nitrate radical, described below. Table I gives representative trace-gas removal rates for these three processes. In spite of these competing reactions, HO largely serves as... 

The mechanism of oxidation probably involves in most cases the initial formation of a glycol (15-35) or cyclic ester,and then further oxidation as in 19-7. In line with the electrophilic attack on the alkene, triple-bonds are more resistant to oxidation than double bonds. Terminal triple-bond compounds can be cleaved to carboxylic acids (RC=CHRCOOH) with thallium(III) nitrate or with [bis(trifluoroacetoxy)iodo]pentafluorobenzene, that is, C6F5l(OCOCF3)2, among other reagents. 

Because process mixtures are complex, specialized detectors may substitute for separation efficiency. One specialized detector is the array amperometric detector, which allows selective detection of electrochemically active compounds.23 Electrochemical array detectors are discussed in greater detail in Chapter 5. Many pharmaceutical compounds are chiral, so a detector capable of determining optical purity would be extremely useful in monitoring synthetic reactions. A double-beam circular dichroism detector using a laser as the source was used for the selective detection of chiral cobalt compounds.24 The double-beam, single-source construction reduces the limitations of flicker noise. Chemiluminescence of an ozonized mixture was used as the principle for a sulfur-selective detector used to analyze pesticides, proteins, and blood thiols from rat plasma.25 Chemiluminescence using bis (2,4, 6-trichlorophenyl) oxalate was used for the selective detection of catalytically reduced nitrated polycyclic aromatic hydrocarbons from diesel exhaust.26... 

Cha and co-workers reported that the silver nitrate-mediated heterocyclization of the diastereomerically pure aminoallene 192 gave the desired quinolizidine 193 and 194, both possessing the E double bond geometry, as a 7 1 mixture of diastereomers (Scheme 19.36) [43]. Diastereomeric transition states 197 and 198 were proposed. The quinolizidine 201 was expected to form predominantly from 199. They pointed out that interestingly, the cyclization of a 1 1 mixture of diastereomers of 192 gave a 1 2 mixture of 193 and 194. Compound 193 was successfully converted to the target clavepictine A (195) and B (196). 

If ethylene is treated with nitrating acid, nitroethyl nitrate, N02.CH2.CH20N02 is produced, as has already been mentioned. The nitroethyl alcohol which is first formed by addition of nitric acid is fixed by esterification, whereas the addition compound with HNOs which is first formed at the double bond of benzene is decomposed with elimination of H20 for reasons which have been mentioned repeatedly. This case is therefore analogous to the reactions of bromine with ethylene and with benzene (p. 106). 

Condensations with alkyl nitrites and nitrates, however, are not so generally applicable as the true ethyl acetoacetate reaction, and the possibility is not excluded that they proceed in another way compounds with mobile hydrogen might first he added to the inorganic part of the ester by means of an aldol condensation. The fact that fluorene, which contains no active double bond at all, combines with ethyl nitrate (as well as with ethyl oxalate) and sodium ethoxide in the same way, yielding oci-nitrofluorene, seems to support this second theory (W. Wislicenus). 

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