Question

What is the name of $Co{{F}_{2}}$?

Answer 1

The "international union of pure and applied chemistry" governs the nomenclature of organic and inorganic chemical compounds. The name of a compound should be systematic and be able to depict and determine the unambiguous formula of a chemical compound.

Complete answer:
Some rules for naming simple inorganic chemical compound are
- Compounds with a single negative charge or anions have the suffix -ide.
For example, ${{H}^{-}}$ is hydride.
- The name of the cation or the compound with a positive charge is usually simply the name of the element and followed by the name of the anion.
For example, $CaC{{l}_{2}}$ is calcium chloride.
- Compounds having more than a single positive charge, or cations are labeled using roman numbers after the name of the cation in brackets.
For example, $M{{n}^{+}}$ is manganese(I) and $M{{n}^{2+}}$ is manganese(II), etc.
- Polyatomic anions containing oxygen or oxyanions have suffix -ite for a lesser quantity of oxygen and suffix -ate for the greater quantity of oxygen.
For example, the anion $NO_{3}^{-}$ is written as nitrate, and the anion $NO_{2}^{-}$ is written as nitrite.
In presence of 4 oxyanions, the prefix hypo- is used for a single oxygen atom, and the prefix per- is used for 4 oxygen atoms.
For example, the anion $Cl{{O}^{-}}$ is written as hypochlorite, and the anion $ClO_{4}^{-}$ is written as perchlorate.
- The presence of hydrogen is depicted by either the name hydrogen or the prefix bi-.
For example, the compound $NaHC{{O}_{3}}$ can be called either sodium hydrogen carbonate or sodium bicarbonate.
Now, $Co{{F}_{2}}$ contains +2 positively charged cobalt cation $C{{o}^{+2}}$ and two singly negatively charged fluoride ions ${{F}^{-}}$.
So the name of the compound will be cobalt(II) fluoride.

Note:
It should be noted that ions can be polyatomic. Cations (which are usually metals and positively polyatomic ions) are named before anions (which are usually non-metals and negative polyatomic ions).
Also, some of the prefixes and suffixes indicating oxidation numbers according to the older system are

Oxidation state	Cations and acids	Anions
Lowest	-ous, hypo-	-ite, hypo-
-ous	-ite
-ic	-ate
-ic, per-	-ate, per-
Highest	-ic, hyper-	-ate, hyper-.