Ball-shaped

Fig. 1. (a) The icosahedral Ceo molecule (soccer ball), (b) The C711 molecule as a rugby-ball-shaped molecule. Two Cgo isomers (c) the Cso molecule as an extended rugby-ball-shaped molecule, (d) The Cgo molecule as an icosahedron. 

Melsens Powder. One of the earlier progressive smokeless powds . Its grains were ball shaped with outer layers burning more slowly than inn r layers... 

Robert Curl, Richard Smalley, and Harold Kroto were awarded the Nobel prize in chemistry in 1996 for the discovery of the soccer-ball-shaped molecule C60. This fundamental molecule was the first of a new series of molecular allotropes of carbon. The enthalpy of combustion of C60 is —25 937 kj-mol, and its enthalpy of sublimation is +233 kj-mol There are 90 bonds in C60, of which 60 are single bonds and 30 are double bonds. Like benzene, C60 has... 

Chemists were greatly surprised when soccer-ball-shaped carbon molecules were first identified in 1985, particularly because they might be even more abundant than graphite and diamond The C60 molecule (10) is named buckminsterfullerene after the American architect R. Buckminster Fuller, whose geodesic domes it resembles. Within 2 years, scientists had succeeded in making crystals of buckminsterfullerene the solid samples are called fullerite (Fig. 14.32). The discovery of this molecule and others with similar structures, such as C70, opened up the prospect of a whole new field of chemistry. For instance, the interior of a C60 molecule is big enough to hold an atom of another element, and chemists are now busily preparing a whole new periodic table of these shrink-wrapped atoms. 

Fig. 10.4 Drawings of students (7th grade) about their ideas of atoms in erystals. Left, angled partieles with bondings between them, right ball-shaped partieles in elosest arrangement. The line in the middle indieated a possible breaking edge...

A variety of phosphorus cores can be used. These cores can be di-, tri-, tetra-or hexafunctionalized, enhancing the possibilities to prepare dendrimers of various forms at least for the lower generations ( cauliflower , bow-tie , bolaform, ball shaped). 

Each GaSb whisker is grown from a ball-shaped center and is capped by a spherule containing amorphous Ga as was shown by SAED (no... 

The 1996 Nobel Prize in chemistry was awarded to three American scientists for their identification of a new allotrope of aromatic carbon molecules called fullerenes. These unusual carbon molecules form a closed-cage structure of joined carbon atoms. The original soccer ball-shaped carbon molecule called buckminsterfullerene contained 60 carbon atoms and was nicknamed Bucky Ball in honor of Buckminster Fuller (1859—1983), who used similar shapes in some of his architectural structures. Since then additional organic pentagon structures beyond the original icosahedral fullerene (C ) have been developed, all with an even... 

The dust-air mixture was ignited in the center of the site by the energy release in a ball-shape volume. 

Figure 14.1c illustrates the reaction rate in the well-developed flame at f = 66 ms. The reaction front is nearly ball-shaped. Some nonsymmetries due to... 

The results show that the dynamics of the reaction zone in a turbulent flame can be traced by the evolution of the volatiles oxidation intensity field. Ignited in the ball-shaped volume, the turbulent flame expands as a relatively wide spherical layer containing strong nonuniformities of the reaction rate. Similar nonuniformities were also detected in the experiments by means of direct optical registration of the flame-ball dynamics [10]. Thus, the numerical results qualitatively reflect the influence of dust concentration nonuniformities that existed... 

The soccer ball shaped framework of Cgg was confirmed for the first time by the X-ray crystal structure of 13 [52]. The bridging of the OSO4 unit occurs in the characteristic 1,2-mode to a [6,6] double bond of the fullerene core. The 17 sets of carbons in the C2v-symmetric 13 were assigned using the 2D NMR INADEQUATE technique on the basis of their connectivities [53]. In these experiments C-enriched material was used. The coupling constants fall into three categories, 48, 54—57 and 65-71 Hz. These values can be attributed to the three types of C-C bonds present in 13, namely C(sp )-C(sp ), the longer [5,6], and the shorter [6,6] bonds, respectively [53]. 

NMR spectroscopy results suggested a soccer ball-shaped structure, as illustrated in the figure. Proof of this structure came in 1991, when Joel M. Hawkins, Frederick J. Hollander, and their colleagues at the University of California, Berkeley, crystallized and studied it with X-ray crystallography. This technique, which generally offers exceptionally high resolution, confirmed the astonishing soccer ball frame. 

FuUerenes are generally stable molecitles, but they do enter into chemical reactions. Researchers have managed to replace some of the carbon atoms in buckminsterfullerene with other atoms such as nitrogen, making molecules such as molecule has a soccer ball shape but... 

D being were looking at a ball, the resultant image is produced by the excitation of a ball-shaped pattern of nerve endings in the spherical retina. Each point on the 3-D ball sends a light ray upsilon to a ballshaped region in the spherical retina (Fig. 3.4). 

Figure 1. Schematic comparison of the pentagonal C5- and Cs-type Mon motifs (dark gray) as present, for example, in the ball-shaped Mon i2-(above corresponding to the anion of compound A) and in the Mon i4-type cluster with view perpendicular to that of Fig. 2 (below corresponding to an anion of compound C without defect).

In the case of giant wheel (molybdenum blue) compounds, the general synthetic strategy involves the acidification (pH 1) and reduction of an aqueous molybdate(VI) solution [possible reducing agents iron powder, tin(II) chloride, molybdenum(V) chloride, ascorbic acid, cysteine, hydroxylamine, hypophos-phorous acid, sodium dithionite, or hydrazine sulfate].On the other hand, an icosahedral ball-shaped cluster can be formed in an aqueous Mo(VI)... 

Figure 3. Polyhedral representation of the ball-shaped cluster anion of compound A highlighting the binuclear spacer units (see Fig. 1 highlighting the pentagons).

As mentioned in Section 6.3, band waggoning in the early 1990s resulted in several proposals for uses of fullerene [30a] which until now have not reached fruition. High-temperature fullerene superconductors and a C60F60 lubricant illustrate the point. The latter, ball shaped perfluorinated hydrocarbon, should have revolutionized industry by minimizing friction losses of energy. The compound was synthesized. However, it proved unstable. Moreover, it... 

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