## roman numerals

Katherine Wu 1H
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Joined: Fri Aug 30, 2019 12:15 am
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### roman numerals

I'm confused to what the roman numeral refers to.
In [Ni(CN)4]^-2, the name is tetracyanonickelate (II), so I'm guessing it refers to the -2?

Cynthia Gong 1L
Posts: 51
Joined: Fri Aug 09, 2019 12:15 am

### Re: roman numerals

I believe the II refers to the +2 charge of the nickel in the compound.

Anna Heckler 2C
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Joined: Wed Sep 18, 2019 12:18 am

### Re: roman numerals

The roman numeral indicates the charge of the ion. They are used for elements that can have ions with multiple different charges as a way to specify.

Naneeta Desar 1K
Posts: 106
Joined: Fri Aug 09, 2019 12:15 am

### Re: roman numerals

Many of the transition metals have multiple charged ions therefore the roman numerals clarifies and distinguishes them.

Megan Cao 1I
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Joined: Sat Sep 07, 2019 12:18 am

### Re: roman numerals

the roman numerals refer to the oxidation number of the metal atom/ion

Mariepahos4D
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Joined: Sat Sep 07, 2019 12:19 am

### Re: roman numerals

The roman numerals refer to the charge of the metal in the compound because many metals have multiple possible oxidation states so when writing out the name you would use the roman numerals to specify the charge of the ion. But when writing out the formula you would not include the numerals.

Jainam Shah 4I
Posts: 130
Joined: Fri Aug 30, 2019 12:16 am

### Re: roman numerals

The roman numeral refers to the oxidation state of the transition metal. Many transition metals can have different charges. Further with the Roman numeral you can figure out the charge of a ligand by comparing the charge on the transition metal and the overall charge on the entire complex. For example if you have a complex with nickel and a ligand and the overall complex charge is -1, you can deduce that the ligand's charge should be -3. Nickel has a +2 charge, the ligand has a -3 charge hence the -1 overall charge.

kristi le 2F
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

### Re: roman numerals

The roman numerals refer to the oxidation number of the central metal atom or ion. It can be determined by finding the difference between the charges of the ligands and the overall charge of the molecule.