Trying to name this compound and figure out its oxidation state
[ CoBr2(NH3)3(H2O) ]+
I came up with triammineaquadibromocobalt(II) ion with a +3 oxidation state...but not sure if this is right...
similarily for
[Fe(ox)(Cl)4]3-
I came up with tetrachlorooxalatoferrate(IV) ion guessing that the oxidation state is +4 but I don't think this is right...having trouble with naming, clearly. Any help is appreciated :)
To name the compound [CoBr2(NH3)3(H2O)]+ and determine the oxidation state of cobalt, we need to follow the rules for naming coordination compounds.
1. Start by identifying the central metal atom. In this case, it is cobalt (Co).
2. Count the total number of ligands attached to the central metal atom. Ligands are the NH3 and H2O molecules in this compound.
- There are three NH3 (ammonia) ligands.
- There is one H2O (water) ligand.
- There are two Br (bromide) ligands.
3. Indicate the number of each ligand in parentheses immediately following the ligand name.
- (NH3)3 indicates three ammonia ligands.
- (H2O) indicates one water ligand.
- (Br2) indicates two bromide ligands.
4. Now, write the name of the ligands in alphabetical order, followed by the metal atom name.
- Bromide (Br) comes before ammonia (NH3) in alphabetical order.
- The metal atom, cobalt (Co), comes last.
5. Use numerical prefixes to denote the number of ligands.
- Tri- indicates three ammonia ligands.
- Di- indicates two bromide ligands.
Putting it all together, the name of the compound is triamminetriaquodibromocobalt(II) ion. Note that "tri-" and "di-" are used instead of "tria-" and "di-" to avoid double vowels.
To determine the oxidation state of cobalt, we need to consider the total charge of the compound. The compound is [CoBr2(NH3)3(H2O)]+, indicating a positive charge.
- The two bromide (Br) ligands have a charge of -1 each, giving a total charge of -2.
- The three ammonia (NH3) ligands are neutral, contributing 0 to the total charge.
- The water (H2O) ligand is neutral, contributing 0 to the total charge.
Since the overall charge of the compound is +1, the oxidation state of cobalt (Co) must be +3. Therefore, you were correct in determining the oxidation state as +3.
Now let's move on to naming [Fe(ox)(Cl)4]3-.
1. Identify the central metal atom. In this case, it is iron (Fe).
2. Count the total number of ligands attached to the central metal atom.
- There is one oxalate (ox) ligand.
- There are four chloride (Cl) ligands.
3. Indicate the number of each ligand in parentheses immediately following the ligand name.
- (ox) indicates one oxalate ligand.
- (Cl)4 indicates four chloride ligands.
4. Write the name of the ligands in alphabetical order, followed by the metal atom name.
- Chloride (Cl) comes before oxalate (ox) in alphabetical order.
- The metal atom, iron (Fe), comes last.
5. Use numerical prefixes to denote the number of ligands.
- Tetra- indicates four chloride ligands.
Putting it all together, the name of the compound is tetrachlorooxalatoferrate(III) ion.
To determine the oxidation state of iron (Fe), we need to consider the total charge of the compound. The compound is [Fe(ox)(Cl)4]3-, indicating a negative charge.
- The one oxalate (ox) ligand has a charge of -2.
- Each chloride (Cl) ligand has a charge of -1.
Since the overall charge of the compound is -3, the oxidation state of iron (Fe) must be +3. Therefore, you were correct in determining the oxidation state as +3.
#1 looks ok to me except the oxidation state of Co is +3 and not +2. (+3 Co + (-2) for 2Br = +1 for the ion.
#2 I would do it a little differently.
tetrachloro(oxalato)ferrate(I)
The parentheses around oxalato are not accidental. Check my thinking.