XPS analysis of this element must be careful not to confuse it with a similar binding energy peak from zinc. Sodium, oxygen, and this element make up Graham’s salt. The Gutmann–Beckett method uses NMR spectroscopy of this element’s 31 isotope. A triphenyl derivative (10[1])of this element (10[1])is found in Vaska’s complex and can also be used to create ylides (10[2])(“ILL-ids”) in the (10[1])Wittig reaction. Oxygen and this element can form anions designated as ortho or pyro, (10[1])and also forms a triprotic acid. Alongside nitrogen and potassium, fertilizers report the content of this element. (10[1])For (10[1])10 points, name this element with red and white varieties (10[2])used to light matches. ■END■ (10[1])