Na₃[BN₂] and Na₂K[BN₂]: A Known and a Novel Alkali Metal Dinitridoborate Obtained via Mild Thermal Dehydrogenation

Abstract

Abstract. Na 3 [BN 2 ] and Na 2 K[BN 2 ] were obtained as white polycrystalline powders from the reaction of the respective binary mixtures NaNH 2 :NaBH 4 and NaNH 2 :KBH 4 in molar ratio 2:1 at 873 K and 683 K, respectively, in an argon stream. According to the results of thermal analysis measurements, both compounds are thermally stable only up to 954 K (Na 3 [BN 2 ]) and 712 K (Na 2 K[BN 2 ]), respectively, decomposing under evolution of alkali metal and nitrogen to yield hexagonal BN as final residue, which was identified from powder patterns.

Sr6(BO3)3BN2: An Oxido–Nitrido–Borate Phosphor Featuring BN2 Dumbbells

“…These values are close to the sum of the effective ionic radii of 1.37 Å and the expected angle of 120°. The B–N distances of 1.29–1.31 Å are also in the range reported for linear BN 2 units. − A detailed list of interatomic distances and angles is given in Table .…”

“…The band positions and the respective assignment are summarized in Table . The IR spectrum comprises mainly the asymmetric stretching vibrations of the BO 3 units in the range 1350–1000 cm –1 and the deformation vibrations thereof in the region 820–550 cm –1 . , The strongest peaks in the Raman spectrum belong to the symmetric stretching vibration of BO 3 at 914 cm –1 and the ν s (BN 2 ) vibration at 1071 cm –1 which is characteristic for linear BN 2 units. ,, The band at 1365 cm –1 in the Raman spectrum stems from BN, which sticks to the surface of the Sr 6 (BO 3 ) 3 BN 2 crystal and which we were not able to remove completely. BN was used as starting material in the synthesis which yielded the single crystals but not a phase pure sample.…”

“…49,50 The strongest peaks in the Raman spectrum belong to the symmetric stretching vibration of BO 3 at 914 cm −1 and the ν s (BN 2 ) vibration at 1071 cm −1 which is characteristic for linear BN 2 units. 27,32,35 The band at 1365 cm −1 in the Raman spectrum stems from BN, which sticks to the surface of the Sr 6 (BO 3 ) 3 BN 2 crystal and which we were not able to remove completely. BN was used as starting material in the synthesis which yielded the single crystals but not a phase pure sample.…”

Li4Ba[BN2]2 – Structure and Vibrational Spectra

“…The linear nitridoborate anion [BN 2 ] 3– is isoelectronic with carbon dioxide and it is one of the basic building units in diverse nitridoborates . Such phases form with the alkali metals lithium (α‐ and β‐Li 3 [BN 2 ]) and sodium (Na 3 [BN 2 ] and an ordered phase Na 2 K[BN 2 ]), and the alkaline earth metals . In the latter case, polymorphism has been observed for the calcium and strontium compound and Ba 3 [BN 2 ] 2 shows a distinctly different arrangement of the [BN 2 ] 3– units.…”

Li3BN2 as a Transition Metal Free, High Capacity Cathode for Li‐ion Batteries

“…Li/Li + match the two voltage plateaus during discharge very well, clearly revealing that discharging of α‐Li 3 BN 2 occurs via two reduction steps. Based on the CV curve, the two cathodic peaks can be assigned to the valence state change of N ions in the BN 2 anion from 2 − to 2.5 − for the peak at 2.10 V and from 2.5 − to 3 − for the peak at 1.65 V. The stepwise oxidation of the BN 2 3− anion has also been pointed out in the melt‐phase N 2 /BN 2 3− electrode and in thermal decomposition of Na 2 KBN 2 …”