Bismuth Borates:  One-Dimensional Borate Chains and Nonlinear Optical Properties

Abstract

Three bismuth borates, Bi[B4O6(OH)2]OH (I), BiB2O4F (II), and Bi3[B6O13(OH)] (III), were obtained in boric acid flux at low temperatures and their structures were determined by using single-crystal and powder X-ray diffraction techniques. All these three bismuth borates contain one-dimensional borate chains and crystallize in noncentrosymmetric space groups. I is a hydrated borate, crystallizing in the space group P1 with lattice constants a = 4.300(1) Å, b = 8.587(2) Å, c = 10.518(2) Å, α = 113.11(3)°, β = 100.50(3)°, and γ = 90.36(3)°, and the borate chain consists of a 3-ring (2BO3 + BO4) and a BO3 group. II is a fluoroborate, which crystallizes in the trigonal space group P32 with a = 6.7147(1) Å and c = 6.4688(1) Å, and the borate anion is a 3-fold helix chain formed by extensive linkage of three-membered borate rings (3BO4). III is also a hydrated borate with a structure that is closely related to II, in which one-sixth of the borate groups are in triangular geometry (BO3), which reduces the symmetry to P1, a = 6.6257(1) Å, b =6.6238(1) Å, c = 6.6541(1) Å, and α = 89.998(3)°, β = 89.982(2)°, and γ = 119.992(2)°. All these three bismuth borates exhibit nonlinear optical (NLO) properties.

Structural investigation of bismuth borate glasses and crystalline phases

“…The formation of NBOs expands and weakens the borate structure and consequently lowers T g . We observed that k 0 is approximately constant at 364 nm in the Bi 2 The most interesting result of our UV-visible spectroscopic measurements is the finding of a broad absorption band in the wavelength range of 360-400 nm, just below the optical absorption edge in glasses containing Bi 2 O 3 of 33 mol% and higher. The intensity of this band increases while its center shifts towards longer wavelengths with increase in Bi 2 O 3 concentration (Fig.…”

“…These glasses have some of the highest densities, refractive indices and coefficients for second and third harmonic generation [1][2][3]. Among several inorganic borate crystals for applications in non-linear optical devices [4], bismuth triborate (BiB 3 O 6 ) phase is known to have the highest coefficient for second harmonic generation [2,[5][6][7]. The coefficients of third harmonic generation also increase with Bi 2 O 3 concentration [3].…”

“…The coefficients of third harmonic generation also increase with Bi 2 O 3 concentration [3]. Therefore there is significant interest in the preparation and characterization of bismuth borate glasses, glass ceramics and single crystals for their application in non-linear optics [1][2][3][4][5][6][7].…”

H2InB5O10: A New Pentaborate Constructed from 2D Tetrahedrally Four‐Connected Borate Layers and InO6 Octahedra

“…polyborates, however, are relatively rare, especially for high-valent metal borates. [10][11][12] The small size and high valence imply high local charge accumulation in anhydrous polyborates, which may cause the instability of the structure at high temperature; [13] therefore, it is difficult to synthesize high-valent metal polyborates by conventional solid-state reactions. Recently, remarkable progress has been made in the synthesis of new polyborates by applying improved synthetic routes, such as hydrothermal synthesis [10,11] and boric acid flux methods.…”

“…Recently, remarkable progress has been made in the synthesis of new polyborates by applying improved synthetic routes, such as hydrothermal synthesis [10,11] and boric acid flux methods. [12,14] For example, in the Ln 2 O 3 -B 2 O 3 (Ln = rare earth) system, [15] only three kinds of borates, i.e. oxyborate, [16,17] orthoborate [18,19] and metaborate, [20] tions.…”