Geometry linear

If only one p orbital and the s orbital are hybridised together, then two sp hybrid orbitals are formed. How will these two hybrid orbitals be orientated with respect to each other  

The bond angle will be 180°, so that they will be diametrically opposed to each other. There are 

They will be orthogonal to each other, and also to the two sp hybrid orbitals. If two atoms were hybridised into the sp configuration, then the remaining p orbitals could be empty as in beryllium dichloride, BeCl2 or alternatively, they could form two 7t bonds, each orthogonal to the other, but 

The ethyne molecule is linear. There are two n bonds that restrict rotation, but in this case it is not noticeable, because of the cylindrical symmetry around the a bond. 

If the ethyne molecule is deprotonated it gives rise to an anion, C2H. Draw the shape of this anion, and in particular indicate the direction of the lone pair. 

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Since the form of the electronic wave functions depends also on the coordinate p (in the usual, parametric way), the matrix elements (21) are functions of it too. Thus it looks at first sight as if a lot of cumbersome computations of derivatives of the electronic wave functions have to be carried out. In this case, however, nature was merciful the matrix elements in (21) enter the Hamiltonian matrix weighted with the rotational constant A, which tends to infinity when the molecule reaches linear geometry. This means that only the form of the wave functions, that is, of the matrix elements in (21), in the p 0 limit are really needed. In the above mentioned one-elecbon approximation... 

The basis consisting of the adiabatic electronic functions (we shall call it bent basis ) has a seiious drawback It leads to appearance of the off-diagonal elements that tend to infinity when the molecule reaches linear geometry (i.e., p 0). Thus it is convenient to introduce new electronic basis functions by the transformation... 

One more hybridization scheme is important m organic chemistry It is called sp hybridization and applies when carbon is directly bonded to two atoms as m acetylene The structure of acetylene is shown m Figure 2 18 along with its bond distances and bond angles Its most prominent feature is its linear geometry... 

Its linear geometry makes it easy to pick out a triple bond in a molecular model... 

Acetylene is linear and alkynes have a linear geometry of their X—C=C—Y units The carbon-carbon triple bond m alkynes is com posed of a CT and two tt components The triply bonded carbons are sp hybridized The ct component of the triple bond contains two electrons m an orbital generated by the overlap of sp hybndized orbitals on adja cent carbons Each of these carbons also has two 2p orbitals which over lap m parrs so as to give two tt orbitals each of which contains two electrons... 

Because of the linear geometry required of cumulated dienes cyclic allenes like cycloalkynes are strained unless the rings are fairly large 1 2 Cyclononadiene is the smallest cyclic allene that is sufficiently stable to be isolated and stored conveniently... 

Recently, solicon-tethered thastereoselecdve ISOC reactions have been reported, in which effective control of remote acyclic asymmetry can be achieved fEq 8 91) Whereas ISOC occur stereoselecdvely, INOC proceeds v/ith significandy lower levels of diastereoselecdon The reaction pathways presented in Scheme 8 28 suggest a plausible hypothesis for the observed difference of stereocontrol The enhanced selecdvity in reacdons of silyl nitronates may be due to l,3- illylic strain The near-linear geometry of nitnle oxides precludes such differendadng elements fScheme 8 28 ... 

Many of the nitrosyls studied are 5-coordinate, and analysis of crystallographic results indicates that, in general, in the trigonal bipyramid structures NO is found in the equatorial position in a linear geometry whereas in a square pyramidal structure, there is a bent M—N—O linkage in an apical position. A further point of interest is that in compounds like Ir(NO)Cl2(PPh3)2, the nitrosyl group bends in the more hindered (P—Ir—P) plane. 

The effect of methyl substituents is interesting the classical linear geometry still is preferred over the hydrogen or methyl bridged structure. Furthermore, 3 substitution of a methyl group provides very little or no extra stabilization over the unsubstituted parent system, 172a, R = H. On the other... 

J. Loustau and M. Dillon, Linear Geometry with Computer Graphics (1993)... 

Notice that the zinc atom is associated with only four valence electrons. Although this is less than an octet, the adjacent carbon atoms have no lone pairs available to form multiple bonds. In addition, the formal charge on the zinc atom is zero. Thus, Zn has only four electrons in the optimal Lewis structure of dimethyizinc. This Lewis stmcture shows two pairs of bonding electrons and no lone pairs on the inner atom, so Zn has a steric number of 2. Two pairs of electrons are kept farthest apart when they are arranged along a line. Thus, the C—Zn—C bond angle is 180°, and linear geometry exists around the zinc atom. 

A second example of linear geometry comes from the familiar gas, carbon dioxide ... 

Compounds like triethylaluminum and dimethylzinc that have metal-carbon bonds are rather uncommon. Nevertheless, trigonal planar geometry (.s and linear geometry (.S p) occur frequently in nature. As we show in Section 10-1. these geometries and their corresponding hybridizations occur in molecules with double bonds and triple bonds. 

Complexes with coordination number 2 always adopt linear geometry about the metal cation. 

The magnitude of the indirect nOe effect depends on the geometry of the three-spin system. It is maximum with a linear geometry of the spin system (0 = 180°). When 0 decreases, the distance also decreases, and the direct enhancement at C becomes more and more significant. At 0 = 78°, the direct and indirect nOe effects become equal. With smaller values of 0, the direct contribution rapidly starts to dominate the nOe at C, and a strong positive enhancement results. This means that indirect nOe effects are to be expected mainly when the spins are close to having a linear geometry. 

The geometrically optimized model of BD had a roughly linear conformation. This spontaneous ordering was unexpected given the general orientation of dipolar molecules. Azobenzenes that have permanent dipoles parallel to the molecular axis would intuitively be expected to tend to pair with their dipole oriented in the opposite direction. The linear geometry is probably due to the... 

The higher energy features can indeed be associated with transitions of He lCl(K,v" = 0) ground-state complexes with rigid He I—Cl linear geometries. In contrast to the T-shaped band that is associated with transitions to the most strongly bound intermolecular vibrational level in the excited state without intermolecular vibrational excitation, n = 0, the transitions of the linear conformer access numerous excited intermolecular vibrational levels, n > 1. These levels are delocalized in the angular coordinate and resemble hindered rotor levels with the He atom delocalized about the l Cl molecule. 

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