Heterologous Isomorphic Substitution Induces Optical Property Enhancement for Deep-UV Crystals: a Case in Rb[B₃O₃F₂(OH)₂]

Hydroxyfluorooxoborate (NH4)[C(NH2)3][B3O3F4(OH)] for exploring the effects of cation substitution on structure and optical properties

“…2 When designing the short-wavelength birefringent crystals, the planar π -conjugated unit [BO 3 ] is favored because of the link between structure and properties. 1–3,5–10 However, the cut-off edge of borates will produce an unfavorable redshift if the hanging bonds of terminal oxygen cannot be fully removed. 4 On the other hand, this issue can be successfully solved by adding the extra electronegative F atoms to the borate system or coupling the nonbonding electron of the terminal oxygen with H + ions.…”

“…4 On the other hand, this issue can be successfully solved by adding the extra electronegative F atoms to the borate system or coupling the nonbonding electron of the terminal oxygen with H + ions. 5–8 The polarizability anisotropy of B–O–F–H groups is higher than that of ordinary B–O groups when they are in a preferential arrangement. 7,8,15 These theories hold that utilizing fluorination and hydroxylation techniques, researchers successfully produced a number of hydroxyfluorooxoborates with large birefringence in the region of ultraviolet (UV) and deep-ultraviolet (deep-UV).…”

“…5–8 The polarizability anisotropy of B–O–F–H groups is higher than that of ordinary B–O groups when they are in a preferential arrangement. 7,8,15 These theories hold that utilizing fluorination and hydroxylation techniques, researchers successfully produced a number of hydroxyfluorooxoborates with large birefringence in the region of ultraviolet (UV) and deep-ultraviolet (deep-UV). 7,8 The investigation of hydroxyfluorooxoborate is, however, still in its early stages since difficult requirements must be met for the simultaneous introduction of hydroxyls and fluorine atoms.…”

“…7,8 The investigation of hydroxyfluorooxoborate is, however, still in its early stages since difficult requirements must be met for the simultaneous introduction of hydroxyls and fluorine atoms. 7,8,15…”

“…Designing new functional materials using cation substitution is a successful method that has grown in interest due to its ability to manipulate both structure and properties. 5–8,14 In this communication, a new metal-free hydroxyfluorooxoborate, (NH 4 )[C(NH 2 ) 3 ][B 3 O 3 F 4 (OH)] (abbreviated as AGBF), which is the rare mixed-cation borate containing guanidine, was synthesized based on the recently published A 2 [B 3 O 3 F 4 (OH)] 15 series with isolated [B 3 O 3 F 4 (OH)] rings. The effects of A-site cation substitution on structure and optical properties were studied.…”