Direct observation of monoclinic domains in rhombohedral EuAl3(BO3)4 skeletal microcrystals

Structural, Electronic and Vibrational Properties of YAl3(BO3)4

“…According to the factor group analysis (Table 4) and results of ab initio calculations, one can conclude that two crystallographically independent BO 3 3− ions should produce four spectral bands in the range of ν 1 vibrations, empty gap between 1050-1250 cm −1 and eight spectral bands related to ν 3 vibrations in the range of 1250-1450 cm −1 . Similar characteristics of Infrared spectra observed only for EuAl 3 (BO 3 ) 4 [69] but not for other ReM 3 (BO 3 ) 4 [34,63,[66][67][68].…”

“…Based on current research results the future activities can be aimed to obtain the vibrational spectra of monoclinic domains in ReAl 3 (BO 3 ) 4 , where Re = Y or rare-earth elements (with the exception of EuAl 3 (BO 3 ) 4 [69]), or vibrational spectra of ReAl 3 (BO 3 ) 4 with totally monoclinic structure.…”

“…The presence of the band at 1100 cm −1 has been attributed to the presence of monoclinically ordered domains incorporated into the trigonal structure [68]. Recently, the monoclinic domains have been observed directly in EuAl 3 (BO 3 ) 4 by means of high resolution transmission electron microscopy (HRTEM) investigations [69] and extra bands in Infrared spectra have been also observed. However, the group of extra peaks (in comparison with observed for YAl 3 (BO 3 ) 4 ) clearly seen in Infrared spectra of EuAl 3 (BO 3 ) 4 in the area of stretching vibrations of [BO 3 ] 3− ions at 872, 931, 980 and 1050 cm −1 .…”

Monoclinic SmAl3(BO3)4: synthesis, structural and spectroscopic properties

“…The published unit-cell parameters of monoclinic TbAl 3 (BO 3 ) 4 and HoAl 3 (BO 3 ) 4 are close to those of PrAl 3 (BO 3 ) 4 and NdAl 3 (BO 3 ) 4 (Wang et al, 1991). Comparison of the unit-cell parameters of the monoclinic borates discussed above (Plachinda & Belokoneva, 2008;Wang et al, 1991;Mazilkin et al, 2019) are presented in Table S1 of the supporting information. Crystallographic data related to the monoclinic polytypes of ReAl 3 (BO 3 ) 4 (denoted ReAB) with the remaining rare-earth ions have not been reported.…”

“…There is no detailed information about the main structural parameters of monoclinic (C2/c) SmAl 3 (BO 3 ) 4 (abbreviated as SmAB). The presence of the C2/c polytypic modification is confirmed for EuAl 3 (BO 3 ) 4 , but a structure refinement was not performed (Mazilkin et al, 2019). The published unit-cell parameters of monoclinic TbAl 3 (BO 3 ) 4 and HoAl 3 (BO 3 ) 4 are close to those of PrAl 3 (BO 3 ) 4 and NdAl 3 (BO 3 ) 4 (Wang et al, 1991).…”