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Hydrothermal crystal growth, piezoelectricity, and triboluminescence of KNaNbOF5

“…In either case, temperature, concentration, and pH are critical factors. Crystal growth of the NCS polymorph of KNaNbOF 5 faces an additional challenge since both polymorphs of KNaNbOF 5 can be grown hydrothermally, sometimes from the same solution [11,[14][15][16][17]. Because hydrothermal crystal growth can take multiple days to weeks to obtain large single crystals, crystal growth conditions that ensure the correct polymorph crystallizes must also be targeted.…”

Internal mobility, phase transitions, and ionic conductivity in (NH4)6KZr4F23 and (NH4)6KHf4F23

“…The crystal system and unit cell parameters of the compounds were determined by the reciprocal lattice method: (NH 4 ) 6 KZr 4 F 23 is orthorhombic, a = 30.178 Å, b = 25.150 Å, c = 6.642 Å, Z = 8; (NH 4 ) 6 KHf 4 F 23 is orthorhombic, a = 30.844 Å, b = 23.496 Å, c = 6.803 Å, Z = 8. The IR spectra of these compounds are similar to the IR spectra of (NH 4 ) 6 Li(Na)Zr 4 F 23 [8]; in addi tion to the X ray diffraction data, this fact allows us to assume that the (NH 4 ) 6 KZr(Hf) 4 F 23 compounds have a chain structure analogous to the structure of (NH 4 ) 6 LiZr 4 F 23 [1,2] and, hence, can be treated as potential candidates for compounds with high ionic conductivity.…”

“…Table 1 presented the X ray crystallographic data for α (NH 4 ) 6 KZr 4 F 23 . The unit cell parameters of the α phase were determined by indexing the X ray powder diffraction pattern by an iterative method using unit cell parameters of (NH 4 ) 6 NaZr 4 F 23 [8] found for a single crystal, and the a parameter was decreased twofold. An analogous transition of the high temperature modification to the initial phase within a few days was previously observed for (NH 4 ) 6 Li(Na)Zr 4 F 23 compounds [2,9].The X ray powder diffraction pattern recorded for sample I after the second heating is somewhat different from the X ray diffraction patterns of the initial compound and α modification.…”

Hexafluoro-, heptafluoro-, and octafluoro-salts, and [MnF5n+1]− (n=2, 3, 4) polyfluorometallates of singly charged metal cations, Li+–Cs+, Cu+, Ag+, In+ and Tl+

“…Mixed alkali cation niobium and tantalum heptafluoro complexes (NaANbF 7 , A = K, Rb; NaATaF 7 , A = K, Rb, Cs) have also been reported [56].…”