Linear-eclipsed configurations

Fieure 4 The two possible geometries that have been observed for the hf (CO) lu -//)] monoanion—the linear-eclipsed (left) and bent-staggered [ 2 noW2 (right) configurations... 

Of the three 6B group [(/r-H)M2(CO)io] complexes, the molybdenum derivative is least stable both toward dimer dissociation and toward CO lability. X-Ray diffraction studies have revealed that the [HMo2(CO)io] anion can adopt either a linear/eclipsed ([Et4N] salt) or an appreciably bent/staggered ([(Ph3P)2N] salt) configuration. ... 

The magnesium atom of compound 62a lies on a crystallographic inversion center, and consequently the substituents are in awft-configuration. The structure of 62b shows an eclipsed conformation and leads to steric repulsion between the dicyclopropy-Imethyl groups (Figure 36). As a consequence a slight deviation from linear structure is observed. 

Figure 14 Schematic diagram of various configurations of (NH3)2 in terms of Oi and Oz, the angles between the N—N axis and the Cs symmetry axes of the two molecules. CSeometries occurring above the diagonal are symmetrically related to those depicted in the lower right triangle. The linear configuration is of eclipsed type.

Fischer projections choose the cyclic and planar, //-eclipsed conformation of the carbon skeletons of sugars as a basis, then pull the cycle straight to form a line and orient it so that the more highly oxidized end Cl is located at the top. This projection procedure remained alive for almost a century because inherent symmetry properties in carbohydrates become apparent here in the most simple way. Always remember Fischer projection formulas are the short notations of a/l-eclipsed cyclic conformations, although they look linear (Fig. 4.2.1). The terminal chiral center, C5 in hexoses, is usually R- or, in the Fischer notation, D-configured. 

In a series of subsequent papers, Manset Bastien (2000b, 2001, 2003) investigated several young binaries and found a weak periodic modulation of the intrinsic linear polarization in a few of them. In most cases, however, the stochastic variability dominates and masks the periodic low-amplitude variations. In the eclipsing binary HAEBE star MWC 1080, the observed periodic variations can be due to the eccentricity of the orbit and/or the asymmetric configuration of CS or CB material. The maximum of the observed polarization coincides (as in the case of UXORs) with the eclipse of the primary in this system. 

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