What is a formula unit?

Think of the formula unit as an “ionic molecule”.

are formed when positively charged ions, or cations, and negatively charged ions, or anions, are bonded together by the electrostatic force of attraction and held in giant lattice structures.

Since the cations and anions are stuck together in this giant structure, you can’t say that you’re dealing with molecules.

Instead you get formula units. A formula unit is the smallest whole number ratio that exists between the cations and anions that form an ionic compound.

For example, sodium chloride, ##NaCl##, is formed when sodium cations, ##Na^(+)##, are to chloride anions, ##Cl^(-)##.

These ions come together to form a lattice structure that looks like this

As you can see, the ions are distributed in a ##1:1## ratio, with each sodium cation being surrounded on all sides by chloride anions and vice versa.

Each unit cell contains an equal number of sodium cations and an equal number of chloride anions.

This means that the formula unit of sodium chloride, i.e. the empirical formula that best describes this ionic compound, is ##NaCl##.

So, as a conclusion, you can think of the formula unit as being for (and for that form covalent networks) what a molecule is for .

Show more

Calculate Your Essay Price
(550 words)

Approximate price: $22

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
The price is based on these factors:
Academic level
Number of pages
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more

Order your essay today and save 10% with the coupon code: best10