Note 347 — Chapter IX · SYSTEMATIC ANALYSIS FOR THE COMMON METAL IONS. THE IONS OF THE ALKALIES AND OF THE ALKALINE EARTHS. ORDER OF PRECIPITATION OF DIFFICULTLY SOLUBLE SALTS WITH A COMMON ION
Reading edition
In that case the salts would be called "complex" salts, salts of a complex ion, MgCl3−. See Chapter XII. They are really "double salts"; cf. Smith, General Inorganic Chemistry, p. 536.