Redetermination of the borax structure from laboratory X-ray data at 145 K

Abstract

The title compound, sodium tetraborate decahydrate (mineral name: borax), Na2[B4O5(OH)4]·8H2O, has been studied previously using X-ray [Morimoto (1956). Miner. J. 2, 1–18] and neutron [Levy & Lisensky (1978). Acta Cryst. B34, 3502–3510] diffraction data. The structure contains tetra­borate anions [B4O5(OH)4]2− with twofold rotation symmetry, which form hydrogen-bonded chains, and [Na(H2O)6] octa­hedra that form zigzag chains [Na(H2O)4/2(H2O)2/1]. The O—H bond distances obtained from the present redetermination at 145 K are shorter than those in the neutron study by an average of 0.127 (19) Å.

Pentaborate(1-) Salts and a Tetraborate(2-) Salt Derived from C2- or C3-Linked Bis(alkylammonium) Dications: Synthesis, Characterization, and Structural (XRD) Studies

“…[28]. The B-O bond lengths, OBO and BOB angles observed for the [B 4 O 5 (OH) 4 ] 2− and B(OH) 3 motifs are in accord with previous tetraborate(2-)[47][48][49][50][51][52][53][54][55][56] and polyborates with co-crystallized B(OH)3 [32,33,39,55,57,58]; for full details see the Supplementary Information.…”

“…Using Etter nomenclature [46] the H-bond interactions per pentaborate are 3 R2 2 (8) and 1 R2 2 (12) for 2, and 3 R2 2 (8) and 1 C(8) for 3, 7, and 8. Compound 7 adopts the familiar ′herringbone′ structure [29,31] The structural characterization of 9 is considered in more detail in this manuscript since it contains a tetraborate(2-) anion and there are far fewer crystallographic reports in the literature featuring this anion; the anion is found partnered with 2Na + in the well-known borax [47,48] but is less commonly found with non-metal cation [40,[49][50][51][52] or transition metal cation salts [53][54][55][56].…”

Control over the Self-Assembly and Dynamics of Metallacarborane Nanorotors by the Nature of the Polymer Matrix: A Solid-State NMR Study

“…To simplify the correlation pattern, we utilized the recently developed the 2D DQ BR2 1 2 NMR correlation technique , that, in contrast to 2D 11 B– 11 B PDSD, suppresses the relayed spin-diffusion transfer and allows for the evolution of autocorrelation signals when equivalent nuclei are spatially close only. To aid in the interpretation of the 11 B– 11 B DQ BR2 1 2 NMR spectra, we analyzed 11 B– 11 B correlations for model crystalline compounds with known structures. , Nevertheless the interpretations presented below are preliminary, and rigorous discussion would require theoretical extensive simulations of 11 B– 11 B double-quantum coherence evolution in these compact multiple-spin systems (e.g., boron atom no. 11 is directly coupled with five other boron sites).…”

Well-crystallized borax prepared from boron-bearing tailings by sodium roasting and pressure leaching

“…The crystal structure was aggregated to a 2-D network through O-H-O hydrogen bonding involving the water molecules and tetraborate anion atoms. 34,35 Such a structure could contribute to the leaching of boron. In other words, it was valuable to obtain higher boron recovery.…”