Quantification of Illite Content in Sedimentary Rocks Using Magnetic Susceptibility--A Rapid Complement or Alternative to X-Ray Diffraction

2004 ◽  
Vol 74 (5) ◽  
pp. 730-735 ◽  
Author(s):  
D. K. Potter ◽  
P. W.M. Corbett ◽  
S. A. Barclay ◽  
R. S. Haszeldine
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


2010 ◽  
Vol 55 (4) ◽  
pp. 673-675
Author(s):  
G. G. Guseinov ◽  
S. S. Ragimov ◽  
J. Hasani Barbaran ◽  
G. M. Agamirzoeva

Clay Minerals ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 191-203 ◽  
Author(s):  
F. Khormali ◽  
A. Abtahi ◽  
H. R. Owliaie

AbstractClay minerals of calcareous sedimentary rocks of southern Iran, part of the old Tethys area, were investigated in order to determine their origin and distribution, and to reconstruct the palaeoclimate of the area. Chemical analysis, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and thin-section studies were performed on the 16 major sedimentary rocks of the Fars and Kuhgiluyeh Boyerahmad Provinces.Kaolinite, smectite, chlorite, illite, palygorskite and illite-smectite interstratified minerals were detected in the rocks studied. The results revealed that detrital input is possibly the main source of kaolinite, smectite, chlorite and illite, whilein situneoformation during the Tertiary shallow saline and alkaline environment could be the dominant cause of palygorskite occurrences in the sedimentary rocks.The presence of a large amount of kaolinite in the Lower Cretaceous sediments and the absence or rare occurrence of chlorite, smectite, palygorskite and illite are in accordance with the warm and humid climate of that period. Smaller amounts of kaolinite and the occurrence of smectite in Upper Cretaceous sediments indicate the gradual shift from warm and humid to more seasonal climate. The occurrence of palygorskite and smectite and the disappearance of kaolinite in the late Palaeocene sediments indicate the increase in aridity which has probably continued to the present time.


1985 ◽  
Vol 49 (352) ◽  
pp. 393-400 ◽  
Author(s):  
P. H. Nadeau ◽  
M. J. Wilson ◽  
W. J. McHardy ◽  
J. M. Tait

AbstractDiagenetic illitic clays from seven North American bentonites of Ordovician, Devonian, and Cretaceous ages and from three subsurface North Sea sandstones of Permian and Jurassic ages have been examined by X-ray diffraction (XRD) and transmission and scanning electron microscopy (TEM and SEM). XRD indicates that the clays from the bentonites are randomly and regularly interstratified illite/smectites (I/S) with 30–90% illite layers, whereas the clays from the Jurassic and Permian sandstones are regularly interstratified I/S, with 80–90% illite layers, and illite respectively. TEM of shadowed materials shows that randomly interstratified I/S consists primarily of mixtures of elementary smectite and ‘illite’ particles (10 and 20Å thick respectively) and that regularly interstratified I/S and illite consist mainly of ‘illite’ particles 20–50 Å thick and > 50 Å thick respectively. Regularly interstratified I/S from bentonites and sandstones are similar with regard to XRD character and particle thickness distribution. These observations can be rationalized if the interstratified XRD character arises from an interparticle diffraction effect, where the smectite interlayers perceived by XRD, result from adsorption of exchangeable cations and water or organic molecules at the interfaces of particles generally < 50Å thick. A neoformation mechanism is proposed by which smectite is converted to illite with increasing depth of burial in sedimentary rocks, based on dissolution of smectite particles and the precipitation/growth of ‘illite’ particles occurring within a population of thin phyllosilicate crystals.


1994 ◽  
Vol 08 (19) ◽  
pp. 1175-1183 ◽  
Author(s):  
G. RAVI CHANDRA ◽  
B. GOPALA KRISHNA ◽  
S. V. SURYANARAYANA ◽  
T. S. N. MURTHY

The effect of the addition of Sn on the superconducting properties of the Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O y system as functions of Sn concentration and heat treatment has been studied by dc electrical resistance, ac magnetic susceptibility, and X-ray diffraction. Tin addition suppresses the volume fraction of the high T c phase. Samples with Sn > 0.1 show metallic behavior up to LNT. The formation of the Ca 2 PbO 4 phase is promoted by Sn. This depletes the amount of Pb and Ca necessary for the formation of the 2223 phase, thus reducing the volume fraction of the 2223 phase. It is possible that at least a small fraction of tin substitutes some of the cationic sites of the starting composition. The results of the different measurements are presented.


2004 ◽  
Vol 848 ◽  
Author(s):  
Evan Lyle Thomas ◽  
Erin E. Erickson ◽  
Monica Moldovan ◽  
David P. Young ◽  
Julia Y. Chan

AbstractA new member of the LnMIn5 family, ErCoIn5, has been synthesized by a flux-growth method. The structure of ErCoIn5 was determined by single crystal X-ray diffraction. It crystallizes in the tetragonal space group P4/mmm, Z = 1, with lattice parameters a = 4.5400(4) and c = 7.3970(7) Å, and V = 152.46(2) Å3. Electrical resistivity data show metallic behavior. Magnetic susceptibility measurements show this compound to be antiferromagnetic with TN = 5.1 K. We compare these experimental results with those of LaCoIn5 in an effort to better understand the effect of the structural trends observed on the transport and magnetic properties.


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.


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.


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