Flux Synthesis, Crystal Structure, and Luminescence Properties of a New Europium Fluoride−Silicate:  K₅Eu₂FSi₄O₁₃

Abstract

The crystal structure and luminescence properties of flux-grown crystals of a new europium(III) fluoride-silicate, K5Eu2FSi4O13, are reported. The structure consists of octahedral dimers of the composition [Eu2O10F], which are linked by unbranched tetrasilicate chains to form a 3-D framework with 5- and 6-ring channels parallel to the b axis where the K+ cations are located. The sharp peaks in the room-temperature emission spectrum are assigned. The number of lines in the region for the 5D0-->7F0 transition and the relative intensities of the 5D0-->7F1 and 5D0-->7F2 transitions confirm the presence of two local Eu3+ environments and strongly distorted Eu3+-ligand surroundings. The room-temperature fluorescence decay curves are well fit by a single-exponential function yielding a lifetime value of about 2.0 ms. Crystal data: monoclinic, space group P21/m, a=7.1850(2) A, b=5.7981(2) A, c=18.1675(6) A, beta=92.248(2) degrees , and Z=2.

Flux Crystal Growth and Structure Determination of K5Y2FSi4O13

“…Final unit cell parameters were determined by least-squares refinement of 1842 reflections from the data set. The reported atomic coordinates of K 5 Eu 2 FSi 4 O 13 [1] were used as an initial structural model. Difference Fourier calculations and full-matrix least-squares refinement against F2 were performed with SHELXS/L 2 using Shelxle [9,10].…”

“…Rare earth containing silicates have been studied extensively for their magnetic and optical properties with solid state lighting fueling recent drives in silicate materials [1][2][3][4][5]. Fluoride flux crystal growth has been shown to be a good synthetic route for exploratory work in silicates due to the solubility of silica in fluorides, such as NaF and KF [1,[4][5][6][7].…”

“…Fluoride flux crystal growth has been shown to be a good synthetic route for exploratory work in silicates due to the solubility of silica in fluorides, such as NaF and KF [1,[4][5][6][7]. In this work, crystals of K 5 Y 2 FSi 4 O 13 were synthesized using a molten potassium fluoride flux.…”

“…In this work, crystals of K 5 Y 2 FSi 4 O 13 were synthesized using a molten potassium fluoride flux. K 5 Y 2 FSi 4 O 13 is isostructural with K 5 Eu 2 FSi 4 O 13 [1], which was grown out of a molten eutectic flux of MoO 3 and KF. Herein, we report the crystal growth and structure determination of K 5 Y 2 FSi 4 O 13 , which was grown in a reaction that yielded another potassium yttrium silicate with a similar morphology, making separation for property measurements impractical.…”

Hydrothermal synthesis of new rare earth silicate fluorides: A novel class of polar materials

“…However, while partial REE substitution can occur over a wide variety of crystallographic sites (especially substituting for Na, Ca or other rare earth elements) in natural silicate minerals, the occurrence of well-characterized compounds where a lanthanide is the primary occupant of a given site is confined to a much shorter set of silicate fluoride minerals. Several interesting minerals are based on La or Ce [7][8][9][10][11][12][13][14][15], and there are a number of synthetic lanthanide silicate fluorides [16][17][18][19] and alkali-containing lanthanide silicate fluorides [20][21][22][23][24][25][26][27] reported. Focusing on yttrium-based compounds for reasons just discussed we find nine examples among the naturally-occurring silicate fluorides, and these are summarized in Table 1.…”