Pyramid like

Ammonia (NFl ) is pyramidal like PFl and in its electronic ground state there are two versions of tlie numbered equilibrium structure exactly as shown for PFl in figure Al.4.5. The potential barrier between the... 

The central phosphorus atom has one unshared pair and three bonded atoms. The molecule is of type AX3E it should be a trigonal pyramid (like NH3) with a bond angle somewhat less than 109.5° (actually, 104°). 

Because of the recent rash of hurricanes like Katrina and tsunamis, we have become more aware of the need for protection against their violence. Geotextiles play a major role in this protection. Reinforced soil was used by Babylonians 3000 years ago in the construction of their pyramid-like tower, ziggurats. One of these famous towers, the Tower of Babel, collapsed. For thousands of years, the Chinese used wood, straw, and bamboo for soil reinforcement including the construction of the Great Wall. In fact, the Chinese symbol for civil engineering can be translated as earth and wood. The Dutch have made extensive use of natural fibrous materials in their age-old battle with the sea. The Romans employed wood and reed for foundation reinforcement. By the 1920s, cotton fabrics were tested as a... 

Grainer salt is made by surface evaporation of brine in flat pans open to the atmosphere. Heat usually is furnished by steam pipes located a few inches below tlie tank bottom. Crystals form at the surface of the brine and are held tliere temporarily by surface tension. Thus, they grow laterally for awhile and form thin flakes. But, as they grow, they tend to sink and this process imparts a peculiar, hollow pyramid-like structure to them. Such crystals are called hopper crystals. Ultimately, the crystals sink to the bottom where they are scraped to one end of the pan. The crystals are fragile and during handling they break up, finally assuming a flake-like shape. Thus, tlie term flake salt. 

In stereochemical experiments, it cannot be decided whether the planar form, attained via pyramidal inversion of the chiral intermediates (Scheme 13, first line), is a transition state or an intermediate. By calculation (116, 117), however, it can be shown that 16-electron systems of the type C8H8Mn(CO)2, in contrast to the planar structures of such 18-electron systems as C8H8Co(CO)2, are pyramidal, like ammonia, with a barrier to inversion. This barrier should be higher for an acyl substituent than for an ester substituent, in agreement with the experimental results (117). 

One of the strengths of the approach employed here is that we have freedom over the choice of the transition metal for the tip and also the structure of the tip employed. Usually we use Pt and W tips and represent the tip apex as a pyramid-like cluster epitaxed on a substrate that is orientated along some low Miller index crystal plane (for example, 111, 110, or 100 surface planes). Generally we find that the structure of the tip has quite a big impact on the images obtained. Sharp tips, such as those constructed on Pt 100, Pt 111 or W 100 surfaces tend to yield higher resolution images than those obtained with more blunt tips (for example the 111 surface of (bcc) W as shown in Scheme II). However,... 

Alonso, A., and Klink, R. Differential electroresponsiveness of stellate and pyramidal-like cells of medial entorhi-nal cortex layer II. I Neurophysiol 1993, 70 128-143. 

Fig. 4a—d. Lamellar structures in thin films that are not considered further in detail in the present article a Thin film confined between inequivalent walls, where the lower one favors the B-rich domains and the upper one the A-rich domains. Then an arrangement where the interfaces run parallel to the walls requires that thickness D and wavelength X are related as D=(n+1/2)A, n=0,l, 2... b Thin film on a substrate that favors B-rich domains undergo at the order-disorder transition (ODT) of the block copolymer melt a phase separation into a fraction x of thickness nXh and a fraction 1-x of thickness (n+1) Xh, such that D=[xn+(l-x) (n+l)] K if the air also favors B-rich domains, c If the air favors A-rich domains instead, the phase separation happens in a fraction x of thickness (n-l/2)A and a fraction 1-x of thickness (n+ 1/2)X with n= 1,2,3... d If the block copolymer film undergoes dewetting at the substrate, droplets form with a step-pyramide like structure ( Tower of Babel [30]). 

The thiolate ion [Sn(SPh)3] is pyramidal like the Pb analogue, while a phosphine complex Sn[C(PMe2)3]2 has two P atoms of the anion C(PMe2)3 coordinated in a t(f-tbp structure a similar type of coordination is found in several acylpyrazo-lone derivatives.155... 

So far, the amides described have all been in the -1-4 state, but one rare three coordinate compound is U N(SiMe3)2 3(pyramidal, like the lanthanide analogues). Unusual amides... 

CH2 and SO2 are bent tiiatomics. SO3 and NO3 are equilateral triangles. XeOs is a triangular pyramid like NH3. 

Toluene-2,3-dithiol (tdtH2) reacts with SbCl3 to form [SbCl(tdt)] which is probably trigonal pyramidal like the As analogue (q.v.). A 1 2 SbCl3 tdtH2 reaction ratio formed yellow [Sb(tdt)(tdtH)] from which base removes the final proton, but the product is the purple Sb ... 

The electrode surface roughness at low level of coarseness can be increased in some different ways other than dendrites (spongy-like deposit,33 honeycomb-like structure,76,77 pyramid-like deposit,83 etc.) on the microscale. The properties of electrodeposits on nanoscale should be also taken into consideration.84,85 Further investigation will show which one of them is the best for this purpose. This chapter is written in order to initiate it. 

In Chapter 4 by Popov et al., the aspects of the newest developments of the effect of surface morphology of activated electrodes on their electrochemical properties are discussed. These electrodes, consisting of conducting, inert support which is coated with a thin layer of electrocatalyst, have applications in numerous electrochemical processes such as fuel cells, industrial electrolysis, etc. The inert electrodes are activated with electrodeposited metals of different surface morphologies, for example, dendritic, spongy-like, honeycomblike, pyramid-like, cauliflower-like, etc. Importantly, the authors correlate further the quantity of a catalyst and its electrochemical behavior with the size and density of hemispherical active grain. 

Mutarotation has limited, rather diagnostic, significance in food chemistry and technology. Practical use of this reaction is demonstrated in milk powder manufacture. Evaporation of milk at a rate lower than mutarotation of lactose yields a product with less a-lactose isomer, which crystallizes in prism- or pyramid-like form. Fast milk evaporation gives an amorphous mixture of a- and [3-lactose (5.7b). 

Trialkyl phosphines will be pyramidal like ammonia. For there to be no plane of symmetry, the alkyl groups R1, R2 and R3 must all be different. 

There is another class of liquid crystals, the bowlic liquid crystal phase, whose molecules are bowl-like or pyramid-like, as is shown in Figure 1.13. Because of the breaking down of the up-down symmetry, the bowlic phase shows an even higher order and may be able to show ferroelectricity (Lam, 1986 Wang et al., 1989). 

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