Write the formula for the following compound, being sure to use brackets to indicate the coordination sphere.
A) potassium tetrabromo(ortho-phenanthroline)- cobaltate(III)
I have looked for that, extensively, on the web and could not find it.
To write the formula for the compound, we need to understand the coordination and arrangement of atoms in the compound.
First, let's break down the compound name:
- "potassium" indicates the presence of a potassium ion (K+).
- "tetrabromo" suggests there are four bromine atoms (Br) involved.
- "(ortho-phenanthroline)" indicates the presence of the ligand ortho-phenanthroline.
- "cobaltate(III)" indicates that cobalt is present in its +3 oxidation state.
Now, let's construct the formula:
1. Start with the coordination sphere, which includes the central metal (in this case, cobalt) and any ligands directly attached to it (orthophenanthroline).
- "ortho-phenanthroline" acts as a bidentate ligand, meaning it can bond to the metal at two different points.
- The symbol for ortho-phenanthroline is usually denoted as "phen."
- Since there are two binding sites per ligand, we need to multiply the ligand's abbreviation by 2.
- So, ortho-phenanthroline becomes "2phen".
- Attach this to the metal symbol (Co): [Co(2phen)X₄]³⁺, where "X" is a placeholder for the bromine atoms.
2. Since potassium is a cation (K+), it is not part of the coordination sphere but is necessary to balance the charge.
- Add the potassium ion outside the brackets: K[Co(2phen)X₄]³⁺.
3. Finally, we consider the bromine atoms present (tetrabromo).
- "Tetra-" indicates four bromine atoms, so we place a subscript of 4 after the "X" in the coordination sphere.
- The formula now becomes: K[Co(2phen)X₄]³⁺, where X represents Br.
Thus, the formula for the given compound is K[Co(phen)Br₄]³⁺.