Isovalent and aliovalent cation substitutions in the anion sublattice of whitlockite-type ferroelectrics Ca9RE(VO4)7 with RE =Y and Yb

Symmetry Inhomogeneity of Ca9–xZnxEu(PO4)7 Phosphor Determined by Second-Harmonic Generation and Dielectric and Photoluminescence Spectroscopy

“…β-TCP-type compounds are characterized by the variation of the space group based on the degree of distortion of the initial structure induced by heating/cooling and/or isomorphic substitutions. ,, The polar structure with the noncentrosymmetric space group R 3 c and the unit cell parameters a ≈ 10.5 Å and c ≈ 38 Å has a phase transition to a nonpolar structure with the space group R 3̅ c (with the same unit cell) on heating. A further increase in the temperature leads to the formation of another nonpolar structure with the centrosymmetric space group R 3̅ m , characterized by the reduced unit cell parameters a ≈ 10.5 Å and c ≈ 19 Å in comparison with the initial parameters.…”

Gladstone–Dale compatibility, electronic polarizability and vibrational spectroscopy of minerals and inorganic compounds with V4+O and V4+O2 vanadyl groups

“…Note: sherwoodite (Thompson et al, 1958;Evans & Konnert, 1978) is excluded from the table because there are no reliable data on the V 4+ :V 5+ ratio in this mineral and because the 14-vanadoaluminate cluster occurring in its crystal structure might need another treatment in the calculation of optical data. (Zadoya et al, 2020), Ca 9 Y(VO 4 ) 7 (d V-O = 1.562 and 1.595 A ˚) (Titkov et al, 2019), Rb 2 KDy(VO 4 ) 2 (d V-O = 1.637 A ˚) (Rghioui et al, 2019).…”

Three in one: a cadmium bismuth vanadate NLO crystal exhibiting a large second-harmonic generation response and enhanced birefringence

“…[15][16][17][18][19] Notably, Cs 4 V 8 O 22 demonstrates a strong phase-matchable SHG intensity of 12.0 × KDP@1064 nm, largely attributed to the [V 4 O 11 20,21 The rare earth vanadates Ca 9 RE(VO 4 ) 7 (RE = La, Yb, Y) crystallize into a polar space group and exhibit favorable SHG activities of 4 × KDP. 22 Additionally, the main group d 0 transition metal vanadates SrM 2 V 2 O 11 (M = Nb, Ta) feature unique [M 2 V 2 O 11 ] 2− anionic layers, resulting in high SHG efficiencies. 23 These investigations predominantly introduce one or two types of NLO-active units within a single compound.…”