Synthesis and Structure of Some MII/MIII Mixed Fluorides with Pyrochlore and Weberite Related Structures

2006 ◽  
Vol 61 (7) ◽  
pp. 808-812 ◽  
Author(s):  
M. A. Subramanian ◽  
W. J. Marshall ◽  
R.-D. Hoffmann ◽  
A.W. Sleight

New NH4MIIMIIIF6 and MIIMIIIF5 ・ 2H2O compounds with the pyrochlore and weberite structures, respectively, are reported. Structures of NH4CoCrF6, AlZnF5 ・ 2H2O, and GaMnF5 ・ 2H2O were refined using X-ray diffraction data from single crystals. The structures of MgIIAlIIIF5 ・H2O and NH4MgIIAlIIIF6 were refined from powder X-ray diffraction data. Magnetic susceptibility data indicates antiferromagnetic ordering in NH4CoIIVIIIF6 at 7 K but no ordering in NH4CoIICrIIIF6 down to 4.2 K. Electrical conductivity presumably due to protons was observed in MgAlF5 ・ (H2O)2.

1996 ◽  
Vol 453 ◽  
Author(s):  
H.-C. Zur Loye ◽  
P. Núñez ◽  
M. A. Rzeznik

AbstractThe one-dimensional compounds Sr3MgPtO6, Sr3MgIrO6, Sr3MgRhO6, Sr3GdRhO6, have been synthesized and structurally characterized by Rietveld refinement of powder X-ray diffraction data. All four compounds are isostructural with the rhombohedral K4CdCl6-type structure. The structure consists of infinite one-dimensional chains of alternating face-shared MO6 octahedra (M = Pt, Ir, Rh) and M′O6 (M′ = Gd, Mg) trigonal prisms. The strontium cations are located in a distorted square antiprismatic environment. Magnetic susceptibility data show that both Sr3MgIrO6 and Sr3MgRhO6 obey the Curie-Weiss law with θ = −6(1) K, and θ= −15(3)K, respectively. Sr3GdRhO6 obeys the Curie law with μeff = 7.80 B.M, consistent with an oxidation state of +3 for both rhodium and gadolinium.


2019 ◽  
Vol 74 (6) ◽  
pp. 485-489
Author(s):  
Yuan Huang ◽  
Xiu-feng Yu ◽  
Zhen Rong ◽  
Yi-chun Ai ◽  
Kun Qian ◽  
...  

AbstractA new complex [Pr3NH]+ [Mn(dca)3]− · H2O (dicyanamide = dca−) was synthesized, in which the Mn2+ cations are bridged by end-to-end dca anions to form three-dimensional [Mn(dca)3]nn− networks and tripropylammonium cations reside in the cavities of these networks. The complex has been characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, and magnetic measurements. Magnetic susceptibility data indicate ferromagnetic interactions among the MnII ions.


2014 ◽  
Vol 67 (11) ◽  
pp. 1618 ◽  
Author(s):  
Ian A. Gass ◽  
Mousa Asadi ◽  
David W. Lupton ◽  
Boujemaa Moubaraki ◽  
Alan M. Bond ◽  
...  

The mononuclear oxazolidine nitroxide complex [MnII(L•)2](ClO4)2 (1) (L•, 4-dimethyl-2,2-di(2-pyridyl)oxazolidine N-oxide) has been synthesized and investigated using single-crystal X-ray diffraction, variable-temperature magnetic susceptibility measurements, and electrochemistry. The structural analysis reveals bond lengths compatible with a linear L•–MnII–L• arrangement where the ligands are in the neutral ligand form and the central MnII ion is high spin (S = 5/2). Although analysis of the variable-temperature magnetic susceptibility data suggests a strong antiferromagnetic metal–radical interaction, the radical–radical intramolecular interaction could not be determined unambiguously from such fits. The resultant isolated S = 3/2 ground state is confirmed by low-temperature magnetization versus field measurements. Electrochemical studies reveal similar square schemes and redox intermediates to the previously reported analogues [FeII(L•)2][BF4]2 and [CoII(L•)2][NO3]2.


2018 ◽  
Vol 73 (8) ◽  
pp. 571-575
Author(s):  
Yang Jie ◽  
Huang Yuan ◽  
Zhong YouQuan ◽  
Fang Ting ◽  
Hao Fan ◽  
...  

AbstractA new complex [(CH3)3NH]2[Co(NCS)4], in which zero-dimensional [Co(NCS)4]n2− anions are balanced by 2n [(CH3)3NH]+ cations, was synthesized. The complex has been characterized by single X-ray diffraction, infrared spectroscopy, elemental analysis, and magnetic measurements. Magnetic susceptibility data indicate ferromagnetic interactions among the CoII ions.


2012 ◽  
Vol 67 (11) ◽  
pp. 1205-1211 ◽  
Author(s):  
Xiaojuan Tang ◽  
Manfred Speldrich ◽  
Andrei L. Tchougréeff ◽  
Richard Dronskowski

The two isotypic compounds Cr(NCNH2)4Cl2 and Mn(NCNH2)4Cl2 have been synthesized and characterized by X-ray diffraction. They crystallize in the cubic space group Im3̄m (Z = 6) with a = 12:643(2) Å for Cr(NCNH2)4Cl2 and a = 12:821(1) Å for Mn(NCNH2)4Cl2. The divalent transition metal ions are octahedrally coordinated by four H2NCN molecules in equatorial and two chloride ions in axial positions. The magnetic susceptibility data of the four Curie-paramagnetic compounds Cr(NCNH2)4Cl2, Mn(NCNH2)4Cl2, Co(NCNH2)4Cl2, and Ni(NCNH2)4Cl2 have been analyzed in greater detail, including many-body quantum theory.


1998 ◽  
Vol 53 (3-4) ◽  
pp. 150-156
Author(s):  
V. Massarotti ◽  
D. Capsoni ◽  
M. Bini ◽  
C. B. Azzonia ◽  
M. C. Mozzati ◽  
...  

The present paper details the way to determine the cation distribution in mixed oxides with transition ions from the diffraction and magnetic susceptibility data. This approach allows one to determine phase abundances and phase compositions by two combined procedures. By X-ray diffraction Rietveld profile refinement and magnetic susceptibility data analysis it is possible to estimate the ratio and the occupancy factor of paramagnetic ions in different oxidation states. A brief discussion of practical cases is reported. In the Li-Ni-O system the lithium cationic fraction of the ordered phase Li2xNi2-2XO2 increases monotonically with the total lithium fraction xtfor 0.31 < xt< 0.46. In the Li-Mn-O system for 0.36 ≤ xt ≤ 0.53 the Li2MnO3 fraction has been determined, and for the coexistent Li [LiyMn2-y]O4 spinel phase the dependence of y on xthas been evaluated.


1981 ◽  
Vol 34 (3) ◽  
pp. 489 ◽  
Author(s):  
NT Moxon ◽  
PE Fielding ◽  
AK Gregson

Powder X-ray diffraction, e.p.r, and magnetic susceptibility studies on copper 4,4',4'',4'''-tetrasulfonated phthalocyanine, Cu(tspc), and α-copper phthalocyanine, αCu(pc), are reported. Cu(tspc) was found, by analogy with the previously reported structures of the α, β and γ forms of Cu(pc), to have a triclinic unit cell of dimensions a 26.9, b 3.8, c 25.6 �, α 89.9, β 90.0 and γ 95.5�. The e.p.r. and magnetic susceptibility data for both Cu(tspc) and αCu(pc) suggest the presence of exchange interaction. The magnetic susceptibility data are best explained by using an S = � Heisenberg chain model with J -0.84 and -0.71 cm-1 respectively.


2013 ◽  
Vol 68 (9) ◽  
pp. 971-978 ◽  
Author(s):  
Inga Schellenberg ◽  
Ute Ch. Rodewald ◽  
Christian Schwickert ◽  
Matthias Eul ◽  
Rainer Pöttgen

The ternary antimonides RE4T7Sb6 (RE=Gd-Lu; T =Ru, Rh) have been synthesized from the elements by arc-melting and subsequent annealing in an induction furnace. The samples have been characterized by powder X-ray diffraction. Four structures were refined on the basis of single-crystal X-ray diffractometer data: U4Re7Si6 type, space group Im3m with a=862.9(2) pm, wR2=0.0296, 163 F2 values for Er4Ru7Sb6; a=864.1(1) pm, wR2=0.1423, 153 F2 values for Yb4Ru7Sb6; a=872.0(2) pm, wR2=0.0427, 172 F2 values for Tb4Rh7Sb6; and a=868.0(2) pm, wR2=0.0529, 154 F2 values for Er4Rh7Sb6, with 10 variables per refinement. The structures have T1@Sb6 octahedra and slightly distorted RE@T26Sb6 cuboctahedra as building units. The distorted cuboctahedra are condensed via all trapezoidal faces, and this network leaves octahedral voids for the T1 atoms. The ruthenium-based series of compounds was studied by temperature-dependent magnetic susceptibility measurements. Lu4Ru7Sb6 is Pauli-paramagnetic. The antimonides RE4Ru7Sb6 with RE=Dy, Ho, Er, and Tm show Curie-Weiss paramagnetism. Antiferromagnetic ordering occurs at 10.0(5), 5.1(5) and 4.0(5) K for Dy4Ru7Sb6, Ho4Ru7Sb6 and Er4Ru7Sb6, respectively, while Tm4Ru7Sb6 remains paramagnetic. Yb4Ru7Sb6 is an intermediate-valent compound with a reduced magnetic moment of 3.71(1) μB per Yb as compared to 4.54 μB for a free Yb3+ ion


2020 ◽  
Vol 235 (1-2) ◽  
pp. 7-13
Author(s):  
Jutta Kösters ◽  
Christian Paulsen ◽  
Frank Stegemann ◽  
Birgit Heying ◽  
Valérie Galéa-Clolus ◽  
...  

AbstractSystematically twinned olivenite (Cu2(AsO4)OH) single crystals from Cap Garonne, Mine du Pradet, France, were studied by X-ray diffraction: P 21/n, a = 822.69(6) pm, b = 861.88(9) pm, c = 594.06(9) pm, β = 90.000(6)°, wR = 0.0224, 1621 F2 values, 79 variables and a domain ratio of 0.501(1)/0.499(1). The temperature dependence of the magnetic susceptibility was well reproduced with a square-spin cluster model and an antiferromagnetic spin-exchange parameter of J/kB = 157(3) K.


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