What is the correct IUPAC name for PBr2

What is the correct IUPAC name for PBr2

The Correct Answer and Explanation is:

The correct IUPAC name for PBr₂ is phosphorus dibromide.

Explanation

To determine the correct IUPAC name for the compound PBr₂, we need to follow the naming rules for binary molecular compounds. These are compounds formed between two nonmetals. In this case, the elements involved are phosphorus (P) and bromine (Br).

The naming convention involves:

1. Writing the name of the first element using its full name.
2. Writing the name of the second element as if it were an anion, which means changing the ending of the element’s name to -ide.
3. Using prefixes to indicate the number of atoms of each element in the compound.

Let us apply these rules step-by-step:

1. The first element is phosphorus, which is written as-is.
2. The second element is bromine, and when converted to an anion form for naming, it becomes bromide.
3. The prefixes we use are based on the number of atoms. The prefixes are:
   • 1: mono
   • 2: di
   • 3: tri
   • 4: tetra
   • 5: penta
   • 6: hexa

In the formula PBr₂, there is one phosphorus atom and two bromine atoms. We do not usually write mono- for the first element if there is only one atom, so “phosphorus” is written without a prefix. Since there are two bromine atoms, we use the prefix di-, and the element becomes dibromide.

So, the full name becomes phosphorus dibromide.

This systematic naming allows chemists to understand the composition of the compound just by reading its name. The use of prefixes is important because elements can form multiple compounds with different ratios, and the prefixes help distinguish between them. For example, PBr₃ would be named phosphorus tribromide and has different physical and chemical properties from PBr₂.