Flux Crystal Growth and Structure Determination of K5Y2FSi4O13

Abstract

Single crystals of K 5 Y 2 FSi 4 O 13 were grown out of a molten potassium fluoride flux. Single crystal X-ray diffraction was used to determine the crystal structure. K 5 Y 2 FSi 4 O 13 crystallizes in the monoclinic space group P2 1 /m with a = 7.1567(12) Å , b = 5.7627(9) Å , c = 18.005(3) Å , b = 92.396(4)°, and Z = 2. This compound has a complex three-dimensional structure with corner-sharing YO 5 F and SiO 4 polyhedra. Graphical Abstract Single crystals of K 5 Y 2 FSi 4 O 13 , which crystallize in the monoclinic space group P2 1 /m, were grown out of a molten potassium fluoride flux and characterized by single crystal X-ray diffraction.

Intrinsic blue-white luminescence, luminescence color tunability, synthesis, structure, and polymorphism of K3YSi2O7

“…This is the case for alkali fluoride melts, which are believed to be one of the best solvent systems for oxides, corroborated by the fact that they have been used with great success for the crystal growth of a wide variety of complex oxides, including silicates. 31,32,35,36,[46][47][48] There are of course many reasons why fluoride melts work so well for growing oxide crystals, including their relatively low melt temperatures and extensive capacity for dissolving oxides. In rare earth silicate chemistry, there has been a recent surge in the use of molten fluoride flux growth [49][50][51] as it has been observed that fluorides enable quick dissolution of the rare earth oxides and silicon dioxide 30,31,35,36,[46][47][48][52][53][54][55] so complex oxides can be formed in relatively short reaction times.…”

Fluoride Flux Crystal Growth and Structure Determination of K5Sc2FSi4O13

“…Final unit cell parameters were determined by least-squares refinement of 3813 reflections from the data set. The reported atomic coordinates of K 5 Y 2 FSi 4 O 13 [2] were used as an initial structural model. Difference Fourier calculations and full-matrix least-squares refinement against F2 were performed with WinGX.…”

“…Furthermore, some of these fluxes can act as ''reactive fluxes'' where one or more of the flux components are incorporated into the crystal products. For example, one method to obtain oxyfluoride single crystals, as described herein, is to use molten fluoride fluxes, which are known to act as reactive fluxes in many situations [1][2][3][4].…”

“…The ionic radius of scandium [5] in K 5 Sc 2 FSi 4 O 13 , coupled with the ionic radii of europium and yttrium in K 5 Eu 2 FSi 4 O 13 [6] and K 5 Y 2-FSi 4 O 13 [2], two isostructural compositions that have been published previously, enable us to define the range of trivalent cations that are accommodated by this structure and, thus, to establish the ionic radii size limits of 0.745-0.947 Å for the lanthanide sites in this composition. This extensive size range suggests that this host structure has the ability accommodate other rare earth ions to yield compositions that exhibit luminescence and can be fine tuned to a desired coloring.…”

“…4). The K(1) ion occupies a site in the channel between the fluorine sites that runs down the b axis, the K(2) occupies a site in the channel between the Si(3) tetrahedra down the b axis, K(3) occupies a site in the channel between Si(1) and Si(2), almost in line with O(3) down the b axis, K(4) …”