An ionic liquid can be formed by adding ZnCl₂ to (2-chloroethyl)trimethylammonium chloride, XCl. When the ratio of ZnCl₂ : XCl = 2 : 1, fast atom bombardment mass spectrometry shows the presence of [Zn_xCl_y]^z− ions with m/z = 171, 307 and 443. Suggest identities for these ions and write a series of equilibria to account for their formation.