Type species

Another example of steric selectivity involves the homopoly and heteropoly ions of molybdenum, tungsten, etc. Each molybdenum(VI) and tungsten(VI) ion is octahedraHy coordinated to six oxygen (0x0) ligands. Chromium (VT) is too small and forms only the weU-known chromate-type species having four 0x0 ligands. The abiUty of other cations to participate in stable heteropoly ion formation is also size related. 

Arsinsaure, /. arsonic acid, arsinic acid (better translated arsonic acid when referring to compounds of the formula RAsO(OH)a). Art,/, kind, sort, type, species, variety nature manner, way race, breed pi, manners (Biol.) species. (Used as a suffix to give a generic meaning as, Pecharten, pitches, kinds of pitch.)... 

We can understand this powerful generalization directly from our view of the valence shell in Werner-type complexes as laid out in Chapter 2. Recall that as an extreme limit for Werner-type species, we consider the metal contribution to the valence shell for the first-row elements as 45 and 4p, with 3d orbitals excluded. So,... 

In order to investigate whether COj reacts in a concerted way with surface carbon or whether it dissociates first to CO and adsorbed oxygen and the adsorbed oxygen reacts, infrared spectroscopy, pulse reactor studies and XANES measuremerrts were used. The i.r. spectrum of a prereduced (Ihour at 675K in S /oHj/Nj) Pt/ZrOj catalyst in contact with CO2 at 775K is shown in Fig 6 The spectrum shows the presence of linearly bound CO on Pt at 2053 cm [15]. Additionally, bands of carbonate type species appeared in the region between 1375 and 1540 cm . Over pure supports (in the absence of Pt) the CO band was not seen, but peaks in the carbonate region were observed... 

Finally, we can see that, neutral meolecules, either in nitro-type or in aci-nitro-type, are more stable than acid-dissociated anions the anion formation is a high endothermic reaction. The energy difference between neutral molecules and acid-dissociated anions calculated at the MP2/6311+-I-G level is 1539 kJ/mol for nitro-type species, and 1683 kJ/mol for aci-nitro-type species. It is clear that, in these conditions, the acid dissociation of the neutral molecules can hardly occur.in pure nitromethane solutions. It provides another theoretieal support for nitromethane as an ideal model of aprotic solvents. 

In either neutral molecules or acid-dissociated anions, the nitro-type species are more stable than the aci-nitro-type species. The 1,3-intramolecular hydrogen rearrangment is a high barrier process. In the tautomeric system formed via the 1,3-hydrogen shift, the equilibrium is therefore strongly displaced to the side of nitro-type species. 

During aging and startup/shutdown, the authors found that poisoning by carbonate-type species was not a major issue. Rather, by HR-TEM and CO chemisorption, the authors concluded that sintering of Pt occurred, with clusters growing from about 1.5 nm to 2.7 nm over the aging period. 

Ochtodes Type species from the West Indies and also occurs in... 

Interestingly Gokel has demonstrated the existence of a direct coordination coupling pathway between this ferrocene cryptand and a silver cation. Complexation studies were carried out with [24] and [25] (as well as other ferrocene cryptand-type species) by X-ray crystallography, FAB mass spectral analysis, nmr and UV/Vis spectroscopy. 

Base catalyzed equilibrations of hydroxyl terminated siloxane oligomers can also be achieved, however these systems can sometimes be complicated by the attack of base to the (OH) end groups to form [(CH2)x 0- X+] type species, which may also cleave the siloxane bonds. This generally results in the loss of terminal functionality in the oligomers produced, which is of course not desirable. 

The necessity of forcing activation conditions has been attributed to the production of various carbonaceous species during activation. Under oxidizing atmospheres, the appearance of stretching frequencies consistent with the formation of surface carboxy-lates has been reported. Similarly, several persistent surface bands consistent with coke-type species were identified when activating supported Ru DENs under H2. °... 

In situ EPR experiments in the presence of different substrates (allyl alcohol, benzene, phenol, or toluene) reveal that type A species is involved in epoxidation reactions. Species B is more active than A in ring hydroxylation reactions. A comparison of the toluene results with those of phenol/benzene suggests that while species B is involved in ring hydroxylations, the A-type species are possibly involved in... 

Study title Key study findings Study type Species/strain... 

For the heteronuclear (HEN) A2B-type species, the symmetry operator was = 1(82) Ye 82)- In this case the nuclear operator was a singlet for H parrs and symmetric for D pairs. Finally for the HEN HDT-type isotopomer we had = e(82). Again in all cases the electron operators represented a singlet. For discussion of the construction of the operators, see, for example, the excellent work of Pauncz [73]. 

It is obvious that the projection operators for the different species have different numbers of terms in them. The HON species have 12 terms (3 x 2 ) while the A2B-type species have four terms, and the HDT+ isotopomer has only two terms. This results in different sizes of the spin-projected basis sets, and for this reason the properties obtained in this work are not precisely comparable between the A3, A2B, and ABC systems, although a very good idea of the trends may be obtained from the data in Table XVI. While all of the above are given in terms of the original particles, it should be noted that the permutations used in the internal particle basis functions are pseudo -permutations induced by the permutations on real particles. 

Peck s hrst signihcant contribution was to look at Thiobacillus thioparus (the type species of the genus Thiobacillus) through the eyes of one who knew a lot about sulfate-reducing bacteria and about the enzymes involved in sulfate metabolism in yeast and mammalian tissues. This led him to think maybe the same enzymes are involved in sulfur oxidation as in reduction. The seminal paper of 1960 showed that this was indeed the case. 

Study type Species No. of animals Cost ( thousands) Test material (Factor Q ) Report (weeks)... 

Based on cp-AFM evidence for the simple case of an n-alkanethiolate/Au SAM, the M structures show no evidence for penetration of metal to form conducting filaments that can cause shorts. The resultant junctions, however, do show extensive formation of reaction product layers with complex chemical compositions which may lead to unfavorable characteristics for molecular device operation. Indeed, in recent reports the use of Ti deposition on LB films, which contain water and inorganic salts at the bottom Pt electrode/LB film interface, leads to formation of inorganic titanium oxide type species in the junction but these complex inorganic layers have also been reported to impart fortuitously quite useful device... 

---