Synthesis and crystal structure of lithium phosphorus nitride Li7PN4: The first compound containing isolated PN4-tetrahedra

Abstract

Single phase Li7PN4 was synthesized under nitrogen atmosphere at 520°C by solid state reaction of L&N and P,N5 with molar ratio 7: 1. Li7PN4 has cubic symmetry, P43n, a = 936.48(3) pm, Z = 8.(Rietveld profile refinement method; X-ray powder diffraction data; R(wp) = 0.099 and R(I, hkl) = 0.0744; 77 nonzero reflections observed, 9 positional parameters refined.) Li,PN, is an ionic solid containing both lithium cations and isolated PN, anions. Atomic arrangement in the solid derives from an anti-fluorite type of structure. The P-N bond lengths (average: 171 pm) correspond to a bond order of approximately 14 in the PN,-tetrahedra. In the cubic unit cell the phosphorus atoms resemble

Li+ Ion Conductors with Adamantane‐Type Nitridophosphate Anions β‐Li10P4N10 and Li13P4N10X3 with X=Cl, Br

“…Powder X-ray diffraction and FTIR spectroscopic analyses confirmed the phase purity of the P 3 N 5 .A ll further steps were performed with strict exclusion of oxygen and moisture in an argonfilled glove box (Unilab, MBraun, Garching, O 2 < 1ppm, H 2 O < 0.1 ppm). LiPN 2 [20] and Li 7 PN 4 [23] were synthesized in sealed silica ampoules under N 2 atmosphere by reaction of Li 3 N( Rockwood Lithium, 94 %) and P 3 N 5 (LiPN 2 :m olar ratio 1.2:1;L i 7 PN 4 :7 .2:1). After grinding the starting materials, they were transferred to aT ac rucible, which was placed in ad ried silica tube.…”

“…Moreover,t he use of constraintso rr estraints yields no appropriate structure refinement.T ypically,P ÀNd istances in lithium nitridophosphates vary from 1.59 to 1.74 . [20,[22][23][24] Distances in the range 1.48 to 1.79 were found in Li 47 B 3 P 14 N 42 . [33] Consequently,i t can be surmised that the extinction observed in the powder pattern clearly indicates an R-centering.…”

“…[6,[15][16][17][18][19] Reactiono ft he binary nitrides P 3 N 5 and Li 3 Nb etween 620 and 800 8Cl ed to four lithium nitridophosphates with different complex P/N anions in am atrix of Li + ions. [20][21][22][23] Recently,w e succeeded in expanding this substance class with two new complex P/N anions by using the multianvil technique in combination with the Li 3 Ns elf-flux method. [22,24] Li 7 PN 4 (620 8C, ambient pressure) is the lithium nitridophosphate with the lowest P/N atomicr atio and consists of non-condensed [PN 4 ] 7À tetrahedra.…”

“…[22,24] Li 7 PN 4 (620 8C, ambient pressure) is the lithium nitridophosphate with the lowest P/N atomicr atio and consists of non-condensed [PN 4 ] 7À tetrahedra. [23] Non-condensed [P 3 N 9 ] 12À dreier-rings, [25,26] which are isoelectronic with [Si 3 O 9 ] 6À ,a re observed in Li 12 P 3 N 9 (790 8C, ambient pressure). [22] At 820 8Ca nd 6GPa,t hese non-condensed [P 3 N 9 ] 12À dreier-rings polymerize to infinite zweierchains of corner-sharing PN 4 tetrahedra (Li 4 PN 3 ).…”

Chain‐Type Lithium Rare‐Earth Nitridosilicates – Li5Ln5Si4N12 with Ln = La, Ce

“…Hereby, the Li2 positions are surrounded by Li1 atoms in a tetrahedrally distorted way. Interestingly, the Li1-Li1 distances are quite short [Li1-Li1: 225(6) pm for Li 5 [23,31] The planes spanned by Li1-Li1-Li2 enclose almost a right angle δ = 94.9(2)°for Ln = La, δ = 92.1(2)°for Ln = Ce (cf. Figure 4, right).…”