Which of the following compounds is represented by the formula BF3?

The compound represented by the formula BF3 is boron trifluoride. This designation is derived from the rules of chemical nomenclature, where the prefix "tri-" indicates the presence of three fluoride ions bonded to a boron atom.

In this case, "B" stands for boron, and "F" represents fluorine. Since the subscript '3' indicates that there are three fluorine atoms in the compound, the full name becomes boron trifluoride. This matches the established systematic naming conventions for binary covalent compounds, which use prefixes to denote the number of each element present in the molecule.

The other options incorrectly suggest different halogen atoms or the number of fluorine atoms. For example, boron trichloride would be represented as BCl3, boron pentafluoride would require the formula BF5, and boron dibromide would be noted as BBr2. This illustrates how the naming and formula structures directly correspond to the number and type of atoms in the compound.