Cyclopropane is an interesting hydrocarbon. Instead of having three carbons in a row, the three carbons form a ring, as shown in this perspective drawing (see Figure 2.18 for a prior example of this kind of drawing):

Cyclopropane was at one time used as an anesthetic, but its use was discontinued, in part because it is highly flammable. (b) The three carbon atoms are necessarily in a plane. What do the different wedges mean?

Verified step by step guidance

1. Identify the structure in the image as a cyclic compound with hydroxyl groups attached to the carbon atoms.
2. Note that the wedges and dashed lines indicate the three-dimensional orientation of the bonds.
3. Solid wedges represent bonds coming out of the plane of the paper towards the observer.
4. Dashed wedges represent bonds going into the plane of the paper away from the observer.
5. The straight lines represent bonds that lie in the plane of the paper.

Key Concepts

Cyclopropane Structure

Cyclopropane is a cyclic hydrocarbon consisting of three carbon atoms arranged in a triangular ring. This unique structure leads to angle strain due to the 60-degree bond angles, which are much smaller than the ideal tetrahedral angle of 109.5 degrees found in alkanes. Understanding this geometry is crucial for grasping the reactivity and properties of cyclopropane.

Wedge and Dash Notation

Wedge and dash notation is a way to represent three-dimensional molecular structures on a two-dimensional surface. Solid wedges indicate bonds that project out of the plane towards the viewer, while dashed lines represent bonds that extend behind the plane. This notation helps visualize the spatial arrangement of atoms, which is essential for understanding stereochemistry and molecular interactions.

Flammability of Cyclopropane

Cyclopropane is highly flammable due to its strained ring structure, which makes it more reactive than linear alkanes. The presence of angle strain allows for easier breaking of C-H and C-C bonds, leading to combustion reactions. This property was a significant factor in the discontinuation of its use as an anesthetic, highlighting the importance of understanding the safety implications of chemical structures.