%ADissanayaka Mudiyanselage, Ranuri%AKong, Tai%AXie, Weiwei%BJournal Name: Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials; Journal Volume: 77; Journal Issue: 4 %D2021%I %JJournal Name: Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials; Journal Volume: 77; Journal Issue: 4 %K %MOSTI ID: 10314105 %PMedium: X %TCrystal growth and physical properties of an antiferromagnetic molecule: trans -dibromidotetrakis(acetonitrile)chromium(III) tribromide, [CrBr 2 (NCCH 3 ) 4 ](Br 3 ) %XThe synthesis, crystal structure determination, magnetic properties and bonding interaction analysis of a novel 3 d transition-metal complex, [CrBr 2 (NCCH 3 ) 4 ](Br 3 ), are reported. Single-crystal X-ray diffraction results show that [CrBr 2 (NCCH 3 ) 4 ](Br 3 ) crystallizes in space group C 2/ m (No. 12) with a symmetric tribromide anion and the powder X-ray diffraction results show the high purity of the material specimen. X-ray photoelectron studies with a combination of magnetic measurements demonstrate that Cr adopts the 3+ oxidation state. Based on the Curie–Weiss analysis of magnetic susceptibility data, the Néel temperature is found to be around 2.2 K and the effective moment (μ eff ) of Cr 3+ in [CrBr 2 (NCCH 3 ) 4 ](Br 3 ) is ∼3.8 µ B , which agrees with the theoretical value for Cr 3+ . The direct current magnetic susceptibility of the molecule shows a broad maximum at ∼2.3 K, which is consistent with the theoretical Néel temperature. The maximum temperature, however, shows no clear frequency dependence. Combined with the observed upturn in heat capacity below 2.3 K and the corresponding field dependence, it is speculated that the low-temperature magnetic feature of a broad transition in [CrBr 2 (NCCH 3 ) 4 ](Br 3 ) could originate from a crossover from high spin to low spin for the split d orbital level low-lying states rather than a short-range ordering solely; this is also supported by the molecular orbital diagram obtained from theoretical calculations. %0Journal Article