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. (10[2]-5[1])A triphenyl (10[1])derivative of this element is found (10[1])in Vaska’s (-5[1])complex (10[1])and can also be used to create ylides (“ILL-ids”) in the Wittig reaction. (10[1])Oxygen and this element can form anions designated as ortho or pyro, (-5[1])and also forms a triprotic (-5[1])acid. (10[1])Alongside nitrogen and potassium, fertilizers report (10[1])the content of this element. (10[1])For 10 points, name (-5[1])this element with red and white varieties used to light (10[1])matches. (10[1])■END■ (10[2])