What is the chemical formula for the dichromate ion?

The dichromate ion is represented by the formula Cr₂O₇²⁻. This ion consists of two chromium atoms and seven oxygen atoms, and it carries a net charge of -2. The structure of the dichromate ion exhibits chromium in a +6 oxidation state, which is significant in a variety of chemical processes, including oxidation reactions.

Understanding the configuration of the dichromate ion is essential, especially in inorganic chemistry and analytical chemistry, where it plays a crucial role as an oxidizing agent. The other options represent different species: CrO₄²⁻ corresponds to the chromate ion, CrO₃ is chromium trioxide (not an ion but a molecule), and Cr³⁺ signifies a chromium ion with a +3 charge. Each of these has distinct properties and applications that differ from those of the dichromate ion, highlighting the importance of knowing the specific chemical species involved in various reactions and processes.