# Brackets in chemical formulas

When you have brackets such as $\ce{Zn(NO3)2}$, if there is a coefficient around the formula such as $\ce{2Zn(NO3)2}$, how would you read this? Would there be 2 zinc atoms, 4 nitrogen and 12 oxygen atoms if I am multiplying that out correctly?

• It means $\ce{Zn(NO3)2}$ contains a $\ce{Zn^{2+}}$ ion and 2 $\ce{NO3-}$ ions Sep 27, 2016 at 1:40
• @Atticus283blink the coefficient indicates that there are two units of that molecule.
– JM97
Sep 27, 2016 at 4:28
• @JM97 right i know that but would how does the 2 affect the (NO3)2 ? Would this means there are 4 N and 12 O atoms? Oct 15, 2016 at 21:07
• @Atticus283blink yes, you are right.
– JM97
Oct 16, 2016 at 0:59

$\ce{2Zn(NO3)2}$ can be interpreted differently, depending on the context. The '2' outside of the parenthesis could either refer to two molecules or two moles of substance. In either case, the chemical formula tells you the same thing: that there are two units of $\ce{NO3-}$ for every unit $\ce{Zn^2+}$.
I would write it as zinc (II) nitrate, (read as 'zinc-two-nitrate) The roman numeral (II) refers to the oxidation state of the zinc ion, which is $+2$.