Magnetic Ordering of Ammonium Cations in NH4I, NH4Br, and NH4Cl

Yen, Fei1,2; Meng, Lei1; Gao, Tian3; Hu, Sixia4

2019-09-26

10.1021/acs.jpcc.9b07620

Journal of Physical Chemistry C   影响因子和分区

1932-7447

1932-7455

Different types of magnetism arise mainly from how electrons move and interact with each other. In this work, we show how protons (H+) also exhibit magnetic behavior. We measured the magnetic susceptibility of the ammonium halides and identified pronounced increases at 232, 233, and 243 K for NH4I, NH4Br, and NH4Cl, respectively, all of which coincide with the geometric ordering of their ammonium cations. With extensive literature establishing the fact that the ammonium cations exhibit rotational motion even toward the lowest temperatures, we take into account that the orbital motion of the protons carries a magnetic moment and find it to be larger than that of the paired electrons. Consequently, the structural phase transitions are magnetically driven as the system attempts to lift 8-fold energy degeneracies of the proton orbitals via Jahn-Teller distortions. Our findings identify that NH4+ cations are capable of comprising magnetism which appears to be ubiquitous in ammonia-based molecular solids.

SCI ; EI

英语

通讯

Shanghai Municipal Natural Science Foundation[16ZR1413600]

Chemistry ; Science & Technology - Other Topics ; Materials Science

Chemistry, Physical ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary

WOS:000488334700043

AMER CHEMICAL SOC

20194107520318

Chlorine compounds ; Positive ions ; Ammonia ; Magnetic susceptibility

Magnetism: Basic Concepts and Phenomena:701.2 ; Inorganic Compounds:804.2

Web of Science

1.Harbin Inst Technol Shenzhen, Sch Sci, Shenzhen 518055, Guangdong, Peoples R China
2.Harbin Inst Technol, Key Lab Micronano Optoelect Informat Syst, Minist Ind & Informat Technol, State Key Lab Tunable Laser Technol, Shenzhen 518055, Guangdong, Peoples R China
3.Shanghai Univ Elect Power, Sch Math & Phys, 2588 Changyang Rd, Shanghai 200090, Peoples R China
4.Southern Univ Sci & Technol, Sustech Core Res Facil, 1088 Xueyuan Blvd, Shenzhen 518055, Guangdong, Peoples R China

Yen, Fei,Meng, Lei,Gao, Tian,et al. Magnetic Ordering of Ammonium Cations in NH4I, NH4Br, and NH4Cl[J]. Journal of Physical Chemistry C,2019,123(38):23655-23660.

Yen, Fei,Meng, Lei,Gao, Tian,&Hu, Sixia.(2019).Magnetic Ordering of Ammonium Cations in NH4I, NH4Br, and NH4Cl.Journal of Physical Chemistry C,123(38),23655-23660.

Yen, Fei,et al."Magnetic Ordering of Ammonium Cations in NH4I, NH4Br, and NH4Cl".Journal of Physical Chemistry C 123.38(2019):23655-23660.