Bases borderline

Hard Bases Soft Bases Borderline Cases... 

Hard bases Soft bases Borderline bases... 

Hard bases Borderline bases Soft bases... 

In accordance with the rules of the HSAB principle, hard acids tend to form complexes with hard bases, and soft acids form complexes with soft bases. Borderline acids form complexes with either soft or hard bases. 

Hard Bases Borderline Bases Soft Bases... 

Inferred reserves are producible, but the assumption of their presence is based on limited physical evidence and considerable geologic extrapolation. This places them on the borderline of being considered undiscovered, and the accuracy of the estimate is very poor. 

To be effective, this method must be carried out on samples which have been blanched, and upon peas from which the skins have been removed. The heat applied in blanching drives off gases entrapped in the tissues, and removal of the skins is required to remove air that may be entrapped under them, although it materially slows up the operation and makes it very tedious. In order that there may be consistency in grading, the test must be conducted under closely standardized conditions of temperature and solution concentration. This becomes of considerable importance in borderline cases, and failure to take it into consideration no doubt accounts for some of the inconsistency in results experienced by the industry. The test is not a true measure of tenderness, in that it accounts for variation in skin texture only in so far as maturity affects skin texture. Skin texture is affected by factors other than maturity (4). Other methods for the estimation of maturity based upon density or specific gravity have been suggested by Jodidi (16) and by Lee (22). 

The low stability of the complex 3.6 is consistent with the hard and soft acids and bases principle of Pearson (1963, 1968 Parr and Pearson, 1983 theoretical aspects Pearson, 1989 Chatteraj et al., 1991 monograph Ho, 1977). According to that principle hard acids will tend to complex with hard bases and soft acids with soft bases. Water is a hard base, whereas the nitrosyl ion is classified by Pearson as a borderline acid with a tendency to be soft. 

Hard acids Borderline acids Hard bases ... 

Ahrland et al. (1958) classified a number of Lewis acids as of (a) or (b) type based on the relative affinities for various ions of the ligand atoms. The sequence of stability of complexes is different for classes (a) and (b). With acceptor metal ions of class (a), the affinities of the halide ions lie in the sequence F > Cl > Br > I , whereas with class (b), the sequence is F < Cl" < Br < I . Pearson (1963, 1968) classified acids and bases as hard (class (a)), soft (class (b)) and borderline (Table 1.23). Class (a) acids prefer to link with hard bases, whereas class (b) acids prefer soft bases. Yamada and Tanaka (1975) proposed a softness parameter of metal ions, on the basis of the parameters En (electron donor constant) and H (basicity constant) given by Edwards (1954) (Table 1.24). The softness parameter a is given by a/ a - - P), where a and p are constants characteristic of metal ions. 

They indicated that the softness parameter may reasonably be considered as a quantitative measure of the softness of metal ions and is consistent with the HSAB principle by Pearson (1963, 1968). Wood et al. (1987) have shown experimentally that the relative solubilities of the metals in H20-NaCl-C02 solutions from 200°C to 350°C are consistent with the HSAB principle in chloride-poor solutions, the soft ions Au" " and Ag+ prefer to combine with the soft bisulfide ligand the borderline ions Fe +, Zn +, Pb +, Sb + and Bi- + prefer water, hydroxyl, carbonate or bicarbonate ligands, and the extremely hard Mo + bonds only to the hard anions OH and. Tables 1.23 and 1.24 show the classification of metals and ligands according to the HSAB principle of Ahrland et al. (1958), Pearson (1963, 1968) (Table 1.23) and softness parameter of Yamada and Tanaka (1975) (Table 1.24). Compari.son of Table 1.22 with Tables 1.23 and 1.24 makes it evident that the metals associated with the gold-silver deposits have a relatively soft character, whereas those associated with the base-metal deposits have a relatively hard (or borderline) character. For example, metals that tend to form hard acids (Mn +, Ga +, In- +, Fe +, Sn " ", MoO +, WO " ", CO2) and borderline acids (Fe +, Zn +, Pb +, Sb +) are enriched in the base-metal deposits, whereas metals that tend to form soft acids... 

On occasion, results from one of the participating laboratories will fail to meet established acceptability criteria. In those cases, acceptance or rejection of the method is determined by the CVM based on overall method performance. For example, a method that has borderline but acceptable performance for both precision and accuracy at two of three participating laboratories and fails badly at a third laboratory would probably fail. A method that was a borderline failure in one laboratory but easily passed in the other laboratories could be accepted. 

Denkert C, Budczies J, Kind T, et al. Mass spectrometry-based metabolic profiling reveals different metabolite patterns in invasive ovarian carcinomas and ovarian borderline tumors. Cancer Res. 2006 66 10795-10804. 

Only 32 of which were conducive to degradation because of drastic changes in seasonal temperature. Any borderline cases based on known analytical deviations are given a question mark following the Yes for degradation to <10% of the initial amount. All systems were active microbiologically over the entire 68 week period. 

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