Are both the electron domain geometry and molecular geometry of HCN linear?
Yes, since we have only two groups of valence electrons around the central atom, C:
H : C : : : N :
The electron domain geometry of a molecule refers to the arrangement of electron domains (bonding and non-bonding electron pairs) around the central atom. The molecular geometry refers to the arrangement of atoms only.
For HCN (hydrogen cyanide) molecule,
1. Electron domain geometry: HCN has one hydrogen atom (H), one carbon atom (C), and one nitrogen atom (N). The central atom is carbon (C). Carbon has three electron domains: a triple bond with nitrogen and two lone pairs. This results in a linear electron domain geometry.
2. Molecular geometry: The molecular geometry of HCN is linear because there are no lone pairs on the central carbon atom, and the bond angles between atoms are approximately 180 degrees.
So, both the electron domain geometry and molecular geometry of HCN are linear.
To determine whether both the electron domain geometry and molecular geometry of HCN (hydrogen cyanide) are linear, we need to consider the arrangement of electron domains around the central atom.
The Lewis structure of HCN shows that it consists of one hydrogen atom (H) bonded to a carbon atom (C), which is in turn bonded to a nitrogen atom (N). According to the octet rule, hydrogen requires only two electrons to achieve a full outer shell, while carbon and nitrogen require eight.
Considering the electron domain geometry, we count the number of electron domains around the central atom. In this case, the carbon atom is bonded to the hydrogen atom and the nitrogen atom, resulting in a total of two electron domains.
Based on the electron domain geometry and considering that HCN has two electron domains, the ideal electron domain geometry is linear (180° bond angle).
However, the molecular geometry takes into account the presence of lone pairs on the central atom that may affect the bond angles. In the case of HCN, there are no lone pairs on the central carbon atom, so the molecular geometry remains linear.
In conclusion, both the electron domain geometry and molecular geometry of HCN are linear.