Final answer:
The formula for lithium hydroxide, which is an ionic compound containing the polyatomic ion hydroxide, is written as LiOH. The positive lithium ion and the negative hydroxide ion balance each other out, making parentheses unnecessary.
Step-by-step explanation:
When writing formulas for ionic compounds containing polyatomic ions, we start by writing the symbol and charge of the cation followed by the symbol and charge of the anion. In the case of lithium hydroxide, the cation is lithium (Li+) and the anion is hydroxide (OH−). Since the charges are equal and opposite (one +1 and one -1), they balance each other out without needing additional ions to balance the charge.
Therefore, the formula for lithium hydroxide is LiOH. No parentheses are needed because there's only one hydroxide ion needed to balance the positive charge of one lithium ion.