When a pair of elements form more than one type of covalent compound, Greek prefixes are used to indicate how many of each element are in a compound. For example:
Some of the Greek prefixes are given in the table below:
|Prefix||Number of Particular Element|
Rules for Binary Covalent Compounds
aof a prefix is often dropped when the element begins with a vowel.
For example, for CO the name will be carbon monoxide, and the final
o of mono is dropped. Remember, it's only the final
a. So, the name of ClO2 will be chlorine dioxide, and no
vowels are dropped.
How do you know which element goes first? The element that comes first in the following list "goes" first.
B, Si, C, Sb, As, P, N, H, Te, Se, S, I, Br, Cl, O, F
Finally, H2O, which according to the rules should be called dihydrogen monoxide is always called water, and NH3, or nitrogen trihydride, is always called ammonia.
Before we learn the rule for naming oxyacids, let's learn the rules for naming oxyanions. What are oxyanions? They are anions formed from oxygen and a nonmetal. Here are some examples: ClO4-, ClO3-, ClO2-, ClO-, SO42-, SO32-.
There are two rules for naming these:
Here are examples of the last three rules:
Chemisty, The Central Science, 10th Ed.
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