BaP₆N₁₀NH:Eu²⁺ as a Case Study–An Imidonitridophosphate Showing Luminescence

Abstract

Barium imidonitridophosphate BaP 6 N 10 NH was synthesized at 5GPa and 1000 8Cw ith ah igh-pressureh ightemperature approach using the multianvil technique. Ba(N 3 ) 2 ,P 3 N 5 and NH 4 Cl were used as starting materials, applying ac ombination of azide and mineralizer routes.T he structure elucidationo fB aP 6 N 10 NH (P6 3 , a = 7.5633(11), c = 8.512(2) , Z = 2) was performed by ac ombination of transmission electron microscopy and single-crystal diffraction with microfocused synchrotron radiation. Phase purity was verifiedb yR ietveld refinement. 1 Ha nd 31 Ps olid-state NMR and FTIR spectroscopy are consistentw ith the structure model.T he chemical composition was confirmed by energydispersive X-ray spectroscopy and CHNS analyses. Eu 2 + -dopeds amples of BaP 6 N 10 NH show blue emission upon excitationw ith UV to blue light (l em = 460 nm, fwhm = 2423 cm À1 )r epresenting unprecedentedE u 2 + -luminescence of an imidonitride.problem can be resolved with high-pressure high-temperature syntheses according to the principle of Le Chatelier.D espite their challenging syntheses, the structuralc hemistryo fn itridophosphates is intriguing, as they can reach even higher degrees of condensation (i.e.,atomicratio k of tetrahedra centers and ligands) than oxosilicates (k(P 3 N 5 ) = 0.6, k(SiO 2 ) = 0.5). [2][3][4][5][6][7][8] Thus, nitridophosphates feature triply-bridging N [3] atoms or even edge-sharing PN 4 tetrahedra. [9] Moreover,n itridophosphates have recently been investigated as host materials for Eu 2 + -doped phosphors. [10][11][12] Although the number of nitridophosphate-based phosphors is still limited, the known examples almostc over the entire visible spectrum. For example, MP 2 N 4 :Eu 2 + (M = Ca, Sr,B a) showse missions from 450 to 570 nm, featuring full width at half-maximum (fwhm) values comparable to established nitride-based phosphorm aterials. [10] Furthermore, Eu 2 + -doped quaternary zeolite-like nitridophosphates Ba 3 P 5 N 10 X (X = Cl, Br,I )h aveb een investigated concerning their luminescence properties. [11,12] Ba 3 P 5 N 10 Br,f or example, has been discussed as an atural-white-light single emitter. [12] In contrast, quaternary imidonitridophosphates, which have been discussed as possible intermediates on ther eactionp athway to highly condensed nitridophosphates, are completely unexplored concerningt heir luminescence properties. [8] These H-containing compounds can be synthesized using starting materials like amides, NH 4 Cl, or the underlying ternary imide nitrideH PN 2 . [13][14][15][16][17] For years, only the less condensed alkali metal amide/imide compounds Cs 5 P(NH) 4 (NH 2 ) 2 , Rb 8 [P 4 N 6 (NH) 4 ](NH 2 ) 2 andN a 10 [P 4 N 4 (NH) 6 ](NH 2 ) 6 (NH 3 ) 0.5 have been known,s howing discrete tetrahedra and adamantane-like [P 4 N 10Àx (NH) x ] (10Àx)À cages, respectively. [13][14][15] The highly condensed alkaline earth metal imidonitridophosphates MH 4 P 6 N 12 (M = Mg, Ca, Sr) were the first representativess howing layered network structure types. [8,17] In framework-type SrP...

Nitridophosphate‐Based Ultra‐Narrow‐Band Blue‐Emitters: Luminescence Properties of AEP8N14:Eu2+ (AE=Ca, Sr, Ba)

“…However, corresponding Rietveld refinement did not yield reasonable results. Hence, a combination of transmission electron microscopy (TEM) and diffraction of microfocused synchrotron radiation was used for structure determination as described in previous works . For this purpose, micron‐sized crystals of BaP 8 N 14 were identified on a TEM grid by EDX analysis and selected area electron diffraction.…”

Sr3P3N7: Complementary Approach by Ammonothermal and High‐Pressure Syntheses

“…So far,P /N-network and -layer compounds such as MP 2 N 4 (M = Ca, Sr,B a), Ba 3 P 5 N 10 X (X = Cl, Br,I )o rB aP 6 N 10 NH were used as host lattices, covering emission in almost the entire visible spectrum. [6][7][8][9] Especially,B a 3 P 5 N 10 Br,c rystallizing in az eolite-like structure, exhibits intriguing luminescence properties andi s discussed as anatural-white-light single emitter,demonstrating nicely the potentialofn itridophosphate materials. [7] But in contrastt os ilicates, only af ew nitridophosphates could be synthesized under ambient pressure conditions (e.g., Ca 2 PN 3 ,L i 10 P 4 N 10 ).…”

“…Particularly due to their structural diversity, these compounds exhibit diverse, interesting physical properties, for example luminescence upon doping with Eu 2+ . So far, P/N‐network and ‐layer compounds such as M P 2 N 4 ( M =Ca, Sr, Ba), Ba 3 P 5 N 10 X ( X =Cl, Br, I) or BaP 6 N 10 NH were used as host lattices, covering emission in almost the entire visible spectrum . Especially, Ba 3 P 5 N 10 Br, crystallizing in a zeolite‐like structure, exhibits intriguing luminescence properties and is discussed as a natural‐white‐light single emitter, demonstrating nicely the potential of nitridophosphate materials …”

Please Mind the Gap: Highly Condensed P–N Networks in LiP4N7 and Li3−xP6N11−x(NH)x

“…Expansion along [010] and [001] are 9.2(5)×10 À 6 and 16.9(4)×10 À 6 K À 1 , respectively. The volumetric expansion coefficient of α V = 25.2(8)×10 À 6 K À 1 is comparable to other nitridophosphates with k = 6/11 like BaP 6 N 10 NH (α V = 22.2×10 À 6 K À 1 ), [35] Rb 3 P 6 N 11 (α V = 13.9×10 À 6 K À 1 ), [19] or Cs 3 P 6 N 11 (α V = 13.0×10 À 6 K À 1 ). [19] The error margin in Li 3À x P 6 N 11À x (NH) x is higher and deviation of values larger than in LiP 4 N 7 , since the determination of lattice parameters with Ag K α1 is less exact than with Mo K α1 .…”