Ionic compounds are a type of chemical compound based on metallic cations (positive ions) and non-metallic anions (negative ions). If you want to name an ionic compound, you just need to determine the name of the cation and anion that are present in the compound, taking care to check the endings of the metal names as necessary. First, you must write the name of the non-metal and its new ending followed by the name of the metal. Also, as an additional step in case you are dealing with a transition metal, you will need to determine the charge of the metal ion.
Method 1 of 3: Naming Basic Ionic Compounds
Step 1. Consult a periodic table of elements
By naming ionic compounds, you will find all the information you need in a periodic table. Ionic compounds are formed from a metal (cation) and a nonmetal (anion). Metals are found on the left and center of the periodic table (for example, barium, radium, and lead), and nonmetals can be found on the right side of the table.
- Anions are generally found in groups 15, 16, or 17 of the periodic table. Most versions of the periodic table are color-coded as a way to indicate what the metallic and non-metallic elements are.
- In case you cannot easily access a copy of the table, you can find it online here.
Step 2. Make a note of the ionic compound formula
Imagine that the ionic compound you are working with is NaCl. Write it down on a piece of paper with a pen or pencil, or write "NaCl" on a white board if you are in a classroom.
This is an example of a basic ionic compound. Basic compounds do not contain transition metals and are made up of only two ions
Step 3. Write the name of the non-metal with the ending "uro"
The first part of an ionic compound is the "anion"; that is, a nonmetal. This constitutes the negatively charged ion in the compound and is always written first in ionic compound names followed by the ending "uro". "Cl" is chlorine, so to incorporate the ending "uro", you must get rid of the last letter (the "o" in this case) and add "uro". So "chlorine" becomes "chloride.
This principle for naming anions applies to all the others as well. For example, in an ionic compound, phosphorus becomes "phosphide" and iodine becomes "iodide."
Step 4. Add the name of the metal
The second component of an ionic compound is the metal cation. If necessary, look at the periodic table to find the name for "Na." Since "Na" is sodium, you must write "sodium."
The name of the metal is always written after the nonmetal regardless of the type of ionic compound you are working with
Step 5. Join the names of the cation and anion
After determining the names of the two components of the ionic compound, you will have done most of the work. The only thing left is to join the parts. "NaCl" can be written as sodium chloride.
Step 6. Practice naming more simple ionic compounds
After determining how to name this ionic compound, you can try a few more that are simple. It can help to memorize some common ionic compounds to better understand their names. Don't forget that you don't need to worry about the number of individual ions when naming compounds. Here are some other common ionic compounds:
- Li2S = lithium sulfide
- Ag2S = silver sulfide
- MgCl2 = magnesium chloride
Method 2 of 3: Naming Ionic Compounds with Transition Metals
Step 1. Make a note of the ionic compound formula
For example, imagine that you are dealing with the compound Fe2OR3. You can find the transition metals in the central part of the periodic table. These metals include platinum, gold, and zirconium. In order to take this into account in the name of the ionic compound, you will need to include a Roman numeral.
A little more work is required to name the transition metals in ionic compounds. This is because their oxidation numbers (or charges) are always changing
Step 2. Name the nonmetal by checking the suffix
Consult the periodic table in case you don't remember the name of the anion. Or it's oxygen, so you can get rid of the ending "geno" and add the ending "gone", calling it "rust."
Anions always acquire the suffix "uro" (except when the nonmetal is oxygen, in which case it is called "oxide"). Therefore, you must name the anions the same way regardless of the type of metal they are paired with in an ionic compound
Step 3. Determine the charge of the metal
In case the metal belongs to group 3 or a higher group on the periodic table, you must determine what its charge is. The subscript of the anion with which the metal is paired indicates the charge of the transition metal. Metals have a positive charge, so in this case, you must translate the number 3 from O3 and write that the charge of Fe is +3.
- You can also do the opposite and write that the charge of O is -2.
- In many high school or college level chemistry assignments, you will be given the metal charge.
Step 4. Name the metal and add a Roman numeral to it as needed
If necessary, refer to the periodic table to determine the chemical code for the metal you are working with. Fe is iron and its charge is +3, so you can write iron (III).
Don't forget that you should only use the Roman numeral when writing the name of the ionic compound and not in the formula
Step 5. Combine the names to generate the ionic compound
This part is the same as writing the name of an ionic compound that does not contain a transition metal. In order to name the ionic compound, you must combine the names of the nonmetal and the metal (including the Roman numeral): Fe2OR3 = iron (III) oxide.
Step 6. Use the old-fashioned way of naming compounds instead of Roman numerals
Following the old method, Roman numerals should be replaced by the endings "bear" and "ico" for transition metals. Consider the two ionic components of the compound. In case the numerical charge of the metal is less than that of the nonmetal, you must use the ending "bear". In case the metal charge is higher, you should use the termination "ico".
- The burden of faith2+ is lower than that of oxygen (the charge of Fe3+ is higher), so "Fe" becomes "ferrous". Likewise, you can write the name of Fe2+Or as ferrous oxide.
- Because "Fe" is the symbol for iron, the terms "ferric" and "ferrous" are used to refer to ions that contain iron.
Step 7. Do not use Roman numerals when naming compounds that contain zinc or silver
Zinc (Zn) and silver (Ag) are the two transition metals that have a definite charge, so in ionic compounds that contain them, it is not necessary to borrow the charge of the metal from the subscript of the anion. The charge of zinc will always be +2 and that of silver will always be +1.
For this reason, when describing these elements, it is not necessary to use Roman numerals or the ancient method of naming compounds
Method 3 of 3: Naming Ionic Compounds with Polyatomic Ions
Step 1. Write the formula for the polyatomic ion
Polyatomic ionic compounds are those that contain more than 2 ions. For the most part, polyatomic compounds are made up of a metallic ion and the rest of their ions are non-metallic. As always, you should consult the periodic table to find the names of each ion. Imagine that you are going to work with the compound FeNH4(SW4)2.
Step 2. Locate the metal charge
First, the charge of the ion SO4 is -2. You also know that the number 2 under the parentheses indicates that there are two of these ions. This ion is known as "sulfate" because it is a combination of oxygen and sulfur. So, 2 x -2 = -4. Then the charge of the ammonium or NH ion4 is +1. It is possible to determine that it has this positive charge because ammonia itself is neutral, while ammonia contains 1 more molecule of hydrogen. (Ammonia is so called because it combines 1 molecule of nitrogen and 4 molecules of hydrogen.) If you add -4 and 1, you get -3, which means that the charge of the iron ion (Fe) must be +3 in order to balance it and make the compound neutral.
- The charge of ionic compounds is always neutral. This information can be used to calculate the charge of the metal.
- The charge of the SO ion4 it is -2 because it is negative without the 2 hydrogen atoms that it had when it existed as sulfuric acid.
Step 3. Make a note of the name of the non-metallic ions
Consult the periodic table to remember that "S" is the symbol for sulfur. While ammonium is not an element, it occurs when 1 nitrogen ion combines with 4 hydrogen ions. So, you are working with ammonium and sulfate, or ammonium sulfate.
Ammonia becomes ammonia by acquiring a positive charge, since ammonia itself has a neutral charge
Step 4. Name the metal ions
How you spell the name will vary depending on whether you are using the newer or older method of naming compounds. So to name the metal ion, you can write iron (III) or ferric.
Step 5. Combine the name of the nonmetals with the name of the metal
To name the compound FeNH4(SW4)2, you can write ammonium iron (III) sulfate.