Ba₁₀LuB₁₈O₃₂F₁₃: the first example of borate in the Lu–B–O–F system with the unprecedented FBB [B₉O₂₂]

Abstract

The first example of borate in the Lu–B–O–F system was demonstrated, possessing a short cut-off edge near 190 nm and the novel FBB [B9O22].

Rare-Earth Scandium Borate Fluoride with a Deep-Ultraviolet Cutoff Edge

“…The introduction of fluorine is advantageous to broaden the transmission range and improve the polarizability anisotropy of metal polyhedra, , which is confirmed by the discussion mentioned above. As we all know, rare-earth oxides typically have a high reaction temperature corresponding to a high melting point, while alkali metal fluorides have a relatively low melting point, which makes them easy to decompose and volatilize at high temperatures.…”

“…Additionally, 33 anhydrous rare-earth borate fluorides were discovered (Table S5) based on ICSD and WOSCCD. However, only four cases (12.1%) crystallize in the NCS space group, namely La 2 B 5 O 9 F 3 , Ba 10 LuB 18 O 32 F 13 , Ba 3 La 4 O 4 (BO 3 ) 3 F, and K 11 Sc 5 (B 5 O 10 ) 4 F 6 . This is less than 16.7% in anhydrous rare-earth borate halides and significantly less than 34.9% in all anhydrous borates .…”

“…A wide transmission range is one of the most important considerations in determining the wavelength to reach the DUV region. Generally, it can be considered from the following items: the 2p orbits of B and O in borates are far away from the bottom of the conduction band (CB) and the top of the valence band (VB), so they have high transmittance in a wide wavelength range, which is also one of the important reasons why borates can be used as UV/DUV materials. , Additionally, the absorption edge will also be blue-shifted by introducing the F element with the largest electronegativity, such as AB 4 O 6 F (A = NH 4 , Na, Rb, and Cs) and MB 5 O 7 F 3 (M = Mg, Ca, and Sr) reported by Pan’s group. – As for cations, alkali/alkaline earth metals attract much attention because they do not have d–d or f–f electronic transitions, which is beneficial to the ability of transmission in the DUV region, – such as the short cutoff edge of LiB 3 O 5 (155 nm), CsB 3 O 5 (169 nm), Sr 2 Be 2 B 2 O 7 (165 nm), and Ba 2 Mg­(BO 3 ) 2 (187 nm) et al Moreover, the unfavorable d–d or f–f electronic transitions are absent from trivalent rare-earth cations RE 3+ (RE = Sc, Y, and Lu) with closed-shell electron configurations, which is advantageous to broaden the transparency window of crystals. – The above advantages inspire us to design a compound combining them together with favorable optical properties. However, there have been only 33 cases of reported anhydrous rare-earth borate fluorides so far.…”

Improvement on Magnetocaloric Effect through Structural Evolution in Gadolinium Borate Halides Ba2Gd(BO3)2X (X = F, Cl)

“…Peaks at roughly 739 and 594 cm –1 can be, respectively, assigned as out-of-plane and in-plane degenerate bending vibrations of [BO 3 ] 3– groups. The IR spectra data pinpoint that the coordination modes of B in Ba 2 Gd­(BO 3 ) 2 F are consistent with [BO 3 ] 3– , which confirm the rationality of structure. − …”

BaI3O9H: a new alkaline-earth metal hydroxy iodate with two groups

“…After the test, the collected diffuse reflectance spectrum was converted into absorbance using the Kubellka–Munk remission function: F ( R ) = (1 − R ) 2 /(2 R ) = K / S ( R is reflectance, K is absorption coefficient, S is scattering coefficient), 43,44 and the corresponding experimental band gap value could be estimated in the absorption spectrum by the curve leading part extrapolation method. 45–53…”