Final answer:
The structural formula of cyclobutane is represented as a square with vertices that represent carbon atoms. Each carbon atom is bonded to two hydrogen atoms, although these are not always explicitly shown in the shorthand notation.
Step-by-step explanation:
The structural formula of cyclobutane consists of a ring of four carbon atoms, each bonded to two other carbons and two hydrogen atoms.
In its most common representation, the formula is shown as a square to indicate the cyclic nature of the molecule, with the understanding that the vertices of the square are the carbon atoms. Although the actual molecule is not flat but puckered, for simplicity and clarity, it is often depicted in two dimensions.
The carbon atoms are typically not shown explicitly in this shorthand notation, but it is understood that each corner of the square represents a carbon atom with two hydrogen atoms attached, except where carbons are bonded to each other.