Hashed-wedged line notation

Notice that just as there are several ways of depicting a molecule in the hashed-wedged line notation, there are several correct Fischer projections of the same stereocenter. 

As always with stereochemical problems, it is useful to build models. Draw both molecules and their stereochemistry using the hashed-wedged line notation. Then search for symmetry elements mirror planes and rotational axes. 

Hashed and wedged line notation is introduced in Section 3.3.2... 

Figure 1 -23 Hashed (red) and wedged (blue) line notation for (A) a carbon chain (B) methane (C) ethane (D) ethanol and (E) methoxymethane. Atoms attached by ordinary straight lines lie in the plane of the page. Groups at the ends of hashed lines lie below that plane groups at the ends...

In Summary Determination of organic structures relies on the use of several experimental techniques, including elemental analysis and various forms of spectroscopy. Molecular models are useful aids for the visualization of the spatial arrangements of the atoms in structures. Condensed and bond-line notations are useful shorthand approaches to drawing two-dimensional representations of molecules, whereas hashed-wedged fine formulas provide a means of depicting the atoms and bonds in three dimensions. 

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