On the phosphors Na₅M(WO₄)₄ (M = Y, La–Nd, Sm–Lu, Bi) – crystal structures, thermal decomposition, and optical and magnetic properties

Abstract

An exploration of the crystal chemistry of exciting luminescent title compounds – possible phosphors – is discussed also employing magnetic measurements.

Die ersten zwei Bismutborosulfate – eines davon enthält Oxonium und ein tektosilicatanaloges Anion

“…B. die Wolframate Na 5 R(WO 4 ) 4 isotyp zu Na 5 Bi(WO 4 ) 4 . [9] Daher war es für uns nicht verwunderlich, auch ein reines, isotyp zu den Seltenerdborosulfaten R 2 [B 2 (SO 4 ) 6 ] [8] [20][21][22] und alle Koordinationszahlen konnten durch MAPLE-Rechnungen bestätigt werden (siehe Tabelle S3, S4 und S8). [24][25][26] Wie das Oxoniumbismutborosulfat wurde auch Bi 2 [B 2 (SO 4 ) 6 ] mittels FTIR-Spektroskopie (Abbildung 2 a und S4), UV/Vis-Spektroskopie (Abbildung S5) und Thermogravimetrie (Abbildung 2 b) untersucht.…”

“…The absence of an inversion centre within these tetrahedra often leads to interesting optical properties as they foster non-centrosymmetric coordination environments around emitting cations and thus promote high luminescence probabilities or even non-linear optical properties if the whole crystal structure lacks inversion symmetry. [7][8][9] Borosulfates may further be classified as silicate-analogous in two ways: On the one hand, the anionic substructure so far consists exclusively of borate and sulfate tetrahedra. On the other hand, the boron atoms may be treated as coordinated by sulfate tetrahedra yielding supertetrahedra TX 4 like B(SO 4 ) 4 .…”

The First Bismuth Borosulfates Comprising Oxonium and a Tectosilicate‐Analogous Anion

“…Silicate‐analogous materials comprise tetrahedral basic building units as characteristic structural motif. The absence of an inversion centre within these tetrahedra often leads to interesting optical properties as they foster non‐centrosymmetric coordination environments around emitting cations and thus promote high luminescence probabilities or even non‐linear optical properties if the whole crystal structure lacks inversion symmetry [7–9] . Borosulfates may further be classified as silicate‐analogous in two ways: On the one hand, the anionic substructure so far consists exclusively of borate and sulfate tetrahedra.…”

“…[31] For instance, the tungstates Na 5 R(WO 4 ) 4 crystallise isotypically with Na 5 Bi(WO 4 ) 4 . [9] Hence, we were not astonished that we also discovered a pure bismuth borosulfate isotypic to the rare-earth borosulfates R 2 [B 2 (SO 4 ) 6 ]. [8] The bismuth borosulfate Bi 2 [B 2 (SO 4 ) 6 ] was synthesised solvothermally from as-made Bi 2 [CO 3 ]O 2 (phasepure sample according to Figure S8 in the Supporting Information), boric acid , oleum (65 % SO 3 ) and H 2 SO 4 yielding a colourless phase-pure powder containing single crystals (further details see Supporting Information).…”

“…The absence of an inversion centre within these tetrahedra often leads to interesting optical properties as they foster non-centrosymmetric coordination environments around emitting cations and thus promote high luminescence probabilities or even non-linear optical properties if the whole crystal structure lacks inversion symmetry. [7][8][9] Borosulfates may further be classified as silicate-analogous in two ways: On the one hand, the anionic substructure so far consists exclusively of borate and sulfate tetrahedra. On the other hand, the boron atoms may be treated as coordinated by sulfate tetrahedra yielding supertetrahedra TX 4 like B(SO 4 ) 4 .…”