Die Tetracyanoborsäuren H[B(CN)₄]·n H₂O, n = 0, 1, 2

Abstract

Treatment of an aqueous solution of Na[B(CN) 4 ] with an acidic cation exchange resin leads to a solution of the strong tetracyanoboronic acid. Evaporation of the solution at room temperature yields colourless single crystals of [H 5

Rare‐Earth Tetracyanidoborate Salts – Structural Features and Properties Including Luminescence of [RE­(H2O)8][B(CN)4]3·nH2O and [RE­(H2O)7{κ1N‐B(CN)4}][B(CN)4]2 (RE = Y, Tb, Dy, Ho, Er, Tm, Yb, Lu; n ≤ 3)

“…[16] The tetracyanidoboronic acid was obtained through a cation-exchange process according to ref. [11] by rinsing an aqueous solution of K[B(CN) 4 ] (c ≈ 50 g/L) slowly through a column filled with the strongly acidic cation exchanger Dowex HCR-W2 (Merck). The complete exchange was ensured by a 5.5 times molar excess of the ion exchanger.…”

Chains of Alkaline Metal Cations and Tetracyanidoborato Anions – Syntheses, Structures and Properties of the New [AI(18‐crown‐6)][B(CN)4)] (AI = Cs, Rb)

“…Starting from K[B(CN) 4 ], which is available through a solid-state chemical procedure in molar amounts, [6] the potassium cation can be easily exchanged by Cs or Rb (or other) cations by using an ion exchanger or by means of an acid-base reaction with tetracyanidoboronic acid [23] and a corresponding alkaline metal carbonate or hydroxide. An aqueous solution of the crown ether is added to the solution of the tetracyanidoborates.…”

Protonation versus Oxonium Salt Formation: Basicity and Stability Tuning of Cyanoborate Anions

“…TheH 3 O + salts of anions 1-3 are obtained from hydrochloric acid through extraction in 86-91 %yield (Scheme 1). [6] HCN and CO are the major gaseous decomposition products for all three H 3 O + salts [6] at 120-150 8 8C. [6] (H 3 O)2 and (H 3 O)3 are stable up to 125 and 110 8 8C, respectively.Hence,both oxonium salts are less stable than (H 3 O)1 (T dec = 145 8 8C).…”