Related Experiment Video
Updated: Jun 1, 2026

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand
Published on: September 8, 2016
Bis[3-(dihydroxy-boryl)anilinium] sulfate
Araceli Vega1, Rolando Luna, Hugo Tlahuext
1Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, CP 62209, Cuernavaca, Mexico.
Abstract:
In the title compound, 2C(6)H(9)BNO(2) (+)·SO(4) (2-), the dihydroxy-boryl group of one of the two independent boronic acid mol-ecules participates in (B)O-H⋯O(B) and N-H⋯O(B) hydrogen bonds, while the second is involved mainly in the formation of the charge-assisted heterodimeric synthon -B(OH)(2)⋯(-)O(2)SO(2) (-). These aggregates are further connected through N-H⋯O(sulfate) inter-actions, forming a complex three-dimensional hydrogen-bonded network.
Related Concept Videos
Determining the pH of Salt Solutions
Diazonium Group Substitution: –OH and –H
Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
Weak Base Solutions
Ions as Acids and Bases
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
Preparation of Acid Anhydrides
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...

