The name of the compound NI3 is nitrogen triiodide.
The correct answer and explanation is:
The name of the compound NI₃ is nitrogen triiodide.
Explanation:
NI₃ is a binary compound composed of nitrogen (N) and iodine (I). When naming binary molecular compounds, especially those made of two nonmetals, we follow specific rules called naming covalent compounds or molecular compounds:
- Name the first element using its full elemental name:
The first element in the formula is nitrogen (N), so we start with “nitrogen.” - Name the second element as if it were an anion:
The second element, iodine (I), is named as “iodide” by changing the ending to “-ide.” - Use prefixes to indicate the number of atoms of each element:
Since both nitrogen and iodine are nonmetals, prefixes (mono-, di-, tri-, tetra-, etc.) are used to specify the number of atoms of each element.- For nitrogen: There is 1 nitrogen atom, so usually, the prefix “mono-” could be used. However, when there is only one atom of the first element, the prefix “mono-” is often omitted for simplicity.
- For iodine: There are 3 iodine atoms, so the prefix “tri-“ is used.
Putting it all together:
- “Nitrogen” (no prefix for one atom)
- “Triiodide” (tri- for three iodine atoms, and “iodide” as the anion form of iodine)
Hence, NI₃ is named nitrogen triiodide.
Additional context:
Nitrogen triiodide is a well-known compound for its extreme instability. It is highly sensitive to touch, shock, or even slight disturbance and decomposes explosively, releasing nitrogen gas and iodine vapor. This property makes it a classic demonstration in chemistry education to illustrate explosive decomposition reactions.
The molecular structure consists of one nitrogen atom bonded to three iodine atoms, forming a trigonal pyramidal shape due to the lone pair on nitrogen. The bonds between nitrogen and iodine are relatively weak, which contributes to the compound’s instability.
In summary, the naming of NI₃ as nitrogen triiodide follows standard IUPAC rules for binary covalent compounds — naming the first element fully, the second with an “-ide” ending, and using numerical prefixes to denote the number of atoms present.