Structure and Properties of NaBH₄·2H₂O and NaBH₄

Abstract

NaBH 4 ·2H 2 O and NaBH 4 were studied by single-crystal Xray diffraction and vibrational spectroscopy. In NaBH 4 ·2H 2 O, the BH 4 -anion has a nearly ideal tetrahedral geometry and is bridged with two Na + ions through the tetrahedral edges. The structure does not contain classical hydrogen bonds, but reveals strong dihydrogen bonds of 1.77-1.95 Å. Crystal structures and vibrational spectra of NaBr·2H 2 O and

First-principles prediction of phase stability and crystal structures in Li-Zn and Na-Zn mixed-metal borohydrides

“…However, the crystal structures of both NaBH 4 and Zn(BH4) 2 are not as well established. NaBH 4 has been a subject of many reports 26,27,28,29,4 due to the distribution of H atoms in the structure and an order-disorder phase transition. We therefore perform calculations of the crystal structure of NaBH 4 , finding a candidate low-energy structure that we use in our phase stability analysis of mixed-metal borohydrides.…”

Enclosure of Sodium Tetrahydroborate (NaBH4) in Solidified Aluminosilicate Gels and Microporous Crystalline Solids for Fuel Processing

“…The tetrahedral BH4-anion groups of the NaBH4 crystals could be identified by strong vibration modes at 1143 (4), 2286 (2 4), 2241 (3) and 2390 (2+4) ( [28][29][30][31], and more recently [32]) as shown in Fig. 4.…”

“…Below 40°C NaBH4 creates a stable hydrated form NaBH4 · 2H2O in contact with water. This species dehydrates at about 40°C to water and NaBH4 which leads to the uncontrollable reaction with water [32]. For a further check of the reactivity of NaBH4-salt with water an amount of 26.2 mg of NaBH4 was wetted with 10 ml water in the bulb and heated to 70°C.…”

Solution Structure of Alkaline NaBH4 Solution: A sight From X-ray Scattering

“…The s·i(s) curves remain oscillated near the zero axis, showing that the diffraction experiments and data treatment processes are reliable. , and this assignment is suggested by the crystal structure data [10]; The peak at 0.24 nm is ascribed to the Na + -H 2 O interactions within the first hydration shell of hydrated Na + ions on the basis of the crystal structure of NaBH 4 •2H 2 O [10], the previous findings from X-ray diffraction [11,12], computer simulation [13]and ab initio [14], and the sum of the ionic radius of Na + (0.102 nm) and the size of a water molecule (0.14 nm); The peak at about 0.29 nm can be ascribed to the H-Bonding of bulk water [15]; The second peak at 0.34 nm arises mainly from the octahedral vertexes of hydrated Na + (cis O-O Na+ ) according to (2) 1/2 r Na-O(1) =0.340 nm; The peak at 0.35 nm may be assign to B-W(I) the interaction of the hydrated BH 4 -and the interaction of the contact ion pair (CIP) of Na + and BH 4 -, Na-Na interaction with a hydrated dimmer sodium ions; the peak at 0.396 nm is due to the interaction between octahedral vertexes and O B -H 2 O(I) interaction in the hydrated B(OH) 4 -ion. The peak around 0.43 and 0.47 nm is due to the interactions of Na-O(2) and trans O-O(Na + ), respectively.…”

“…However, the interactions above 0.50 nm are so intricate and are usually the overlapping of several bands that it is difficult to make qualitative descriptions. The theoretical DRDFs of the alkaline NaBH 4 solution are gained by inputting the structural parameters(c, r ij , n ij , b ij ) obtained from the preliminary analysis above and previous studies of Na + and OH -ions in water, and the interatomic distances, computed by atomic coordinates, crystal cell parameters and space-group of NaBH 4 , NaBH 4 •2H 2 O [10]. The structural parameters were allowed to vary until the experimental and calculated structural function curves coincide after 20 nm -1 , and the model-calculated D(r)-4πr2ρ 0 curve presented in Fig.2 from Equ.…”