Different types of bond representations [duplicate]

Question

What do the following different kind of bonds mean?

Although this answer to the question "What are the meanings of dotted and wavy lines in structural formulas?" does describes some of the bonds, it does not provide a complete description and some bonds are not mentioned. Also, the question has a dotted-line bond, which maybe misleading.

Answer 1

Disclaimer: This is topic of ongoing discussion, and different authors use different conventions. This answer is, mostly, based on IUPAC recommendations (2006). This is not a complete list, as there are a vast number of representations for stereochemistry of a compound, Fischer and Newmann projections to name two. Furthermore, in biochemistry, the representations are different.

This page covers the topic in more detail with lots of examples.

Name	Representation	Meaning
Dashed bond		Partial bond in plain of paper or of unspecified stereochemistry. Also represents hydrogen bonds. Also represents bonds with known relative and unknown absolute configuration in an enantiopuric product; similar to hashed wedged bond.
Solid bond		Bond in plain of paper or unspecified stereochemistry.
Hashed wedged bond		Narrow end: towards reader; wide end: away from reader.
Hashed unwedged bond		Both atoms are below the plain of the paper. Also represents configuration of racemates.
Solid wedged bond		Narrow end: away from reader; wide end: towards reader.
Solid unwedged bond		Both atoms are above the plain of the paper. Also represents configuration of racemates.
Hollow unwedged bond		Bonds with known relative and unknown absolute configuration in an enantiopuric product; similar to solid wedged bond
Wavy bond		Bond with unknown stereochemsitry. Also represents an unknown moiety.
Arrow bond		Dative bond in plain of paper or with unknown stereochemsitry.

Controversy Surrounding Hashed Wedged Bond

There is a bit of controversy surrounding the hashed bond.$^\text{1}$

Unfortunately, bonds below the plane of the drawing have historically been represented in many different ways. Each of those representations has involved a bond drawn with small line segments either coincident with or perpendicular to the main axis of the bond. The two schools of thought that prefer the use of a hashed wedge bond assign it two directly opposite interpretations—one school says that the atom at the narrow end should be considered in the plane of the paper, while the other says that the atom at the wide end should be so considered. Additionally, a dashed line often represents a partial bond, delocalization, or a hydrogen bond. The biggest problem is that there is no way to intuit an author’s desired meaning from a chemical structure drawing alone.

Hashed and Solid Wedged Bonds

In the article,$^\text{1}$ IUPAC recommends using the hashed wedge bond in a similar way to that of the solid wedged bond:

In cases where such below-the-plane bonds are required, there is no option that will please everyone. Earlier recommendations 12 proposed the use of an unwedged hashed bond, but today such bonds are in fact encountered in the literature least frequently of all options. This document now recommends the use of a hashed wedged bond interpreted in a sense similar to the solid wedged bond (starting from an atom in the plane of the drawing at the narrow end of the wedge). This recommendation is made primarily because the hashed wedge is easier to analyze visually than the unwedged type, particularly when it is used in a sense similar to the wedged bold bond.

The unwedged hashed or solid bonds are used specifically to indicate that both atoms are below or above the plane, respectively:$^\text{1}$

Strictly speaking, unwedged bold and hashed lines show that both atoms are above or below the plane of the drawing (as is used in Haworth drawings of carbohydrates).

Hashed and Solid Unwedged Bonds

The hollow wedged bond represents bonds with known relative but unknown absolute configuration in enantiopuric compounds. And unwedged hashed and solid bonds are also represents recemates:$^\text{2}$

Wiggly Lines

Although it is not recommended by IUPAC, some authors (e.g., Clayden J., Greeves N., and Warren S. who call it wiggly lines) do use the wavy bond to show an unknown moiety: $^\text{3}$

The Dotted-Line Bond

Note: a dotted-line bond has not been recommended by IUPAC. I have seen it represent an ionic interaction, such as between carboxylate and sodium ions.

References

1. Brecher, J. (2006). Graphical Representation Of Stereochemical Configuration. Pure Appl. Chem., 78(10), 1897–1970. 10.1351/pac200678101897
2. Maehr, H. (2002). Graphic Representation of configuration in Two-Dimensional Space. Current Conventions, Clarifications, and Proposed Extensions. J. Chem. Inf. Comput. Sci, 42, 894-902. 10.1021/ci025518w
3. Clayden J., Greeves N., and Warren S. (2012). Organic Chemistry, $\textit{2}^\textit{nd}$ ed. Oxford University Press Inc., New York