Synthesis and Crystal Structure of the Strontium Beryllate Sr3Be2O5

Beryllates show an interesting and diverse structural chemistry, resembling that of well‐investigated silicates. The coexistence of tetrahedral and trigonal coordination of Be by O atoms in oxoberyllates allows for an even broader variety of structural motives and implies a plurality of possible atomic ratios Be:O in ternary or higher compounds. We have now synthesized the novel strontium oxoberyllate Sr3Be2O5 via a high‐temperature high‐pressure reaction and have structurally characterized the ternary oxide by single‐crystal and powder X‐ray diffraction analysis. Sr3Be2O5, a low condensed oxoberyllate, contains unprecedented [Be2O5]6– double triangles and Sr atoms in both double‐capped trigonal‐prismatic and octahedral coordination. These motifs show striking resemblance to α‐SrBeO2 and SrO, combining their structural properties. Lattice energy (MAPLE) calculations corroborate found parallels to the known phases SrO and α‐SrBeO2

Synthesis and Luminescence Properties of Amber Emitting La7Sr[Si10N19O3] : Eu2+ and Syntheses of the Substitutional Variants RE(8-x)AE(x)[Si10N20-xO2+x] : Eu2+ with RE=La, Ce;AE=Ca, Sr, Ba;0 <= x <= 2

The oxonitridosilicate La7Sr[Si10N19O3] : Eu2+ and its substitutional variants RE(8-x)AE(x)[Si10N20-xO2+x] : Eu2+ with RE=La, Ce;AE=Ca, Sr, Ba and 0 <= x <= 2 were synthesized starting from REN, SrN/Ca3N2/Ba2N, SiO2, amorphous Si3N4 and Eu2O3 as doping agent at 1600 degrees C in a radiofrequency furnace. The crystal structure of La7Sr[Si10N19O3] was solved and refined based on single-crystal X-ray diffraction data. La7Sr[Si10N19O3] crystallizes in the orthorhombic space group Pmn2(1) (no. 31). The crystal structures of the isotypic compounds RE(8-x)AE(x)[Si10N20-xO2+x] were confirmed by Rietveld refinements based on powder X-ray diffraction data using the single-crystal data of La7Sr[Si10N19O3] as starting point. Crystal structure elucidation reveals a 3D network of vertex sharing SiN4 and SiN2(N1/2-x/4O1/2+x/4)(2) (0 <= x <= 2) tetrahedra. When excited with UV to blue light, La7Sr[Si10N19O3] : Eu2+ shows amber luminescence with lambda(em)=612 nm and fwhm=84 nm/2194 cm(-1), which makes it interesting for application in amber phosphor-converted light emitting diodes

HIP to be Square: Simplifying Nitridophosphate Synthesis in a Hot Isostatic Press

(Oxo)Nitridophosphates have recently been identified as a promising compound class for application in the field of solid‐state lighting. Especially, the latest medium‐pressure syntheses under ammonothermal conditions draw attention of the semiconductor and lighting industry on nitridophosphates. In this contribution, we introduce hot isostatic presses as a new type of medium‐pressure synthetic tool, further simplifying nitridophosphate synthesis. In a second step, phosphorus nitride was replaced as starting material by red phosphorus, enabling the synthesis of Ca2PN3 as model compound, starting only from readily available compounds. Moreover, first luminescence investigations on Eu2+‐doped samples reveal Ca2PN3:Eu2+ as a promising broad‐band red‐emitter (λem=650 nm; fwhm=1972 cm−1). Besides simple handling, the presented synthetic method offers access to large sample volumes, and the underlying reaction conditions facilitate single‐crystal growth, required for excellent optical properties