Question

The number of oxygen atoms that are directly attached to one chromium in dichromate ion are ___.

Hint:

In dichromate \( (Cr_2O_7^{2-}) \), each Cr has tetrahedral geometry with 4 oxygen atoms around it.

Answer 1

Step 1: Understanding the Concept:
The dichromate ion (\(Cr_{2}O_{7}^{2-}\)) consists of two tetrahedra sharing one corner. Knowing the structure helps determine the coordination number of the central metal.
Step 2: Detailed Explanation:
In the dichromate ion (\(Cr_{2}O_{7}^{2-}\)):
Each Chromium (Cr) atom is at the center of a tetrahedron.
There are three terminal oxygen atoms attached to each Chromium.
There is one oxygen atom that acts as a bridge between the two Chromium atoms (\(Cr-O-Cr\) linkage).
Therefore, for any single Chromium atom, there are 3 terminal oxygens + 1 bridging oxygen = 4 oxygen atoms directly attached to it.
Step 3: Final Answer:
The number of oxygen atoms directly attached to one chromium is 4.