Band-gap tuning by solid-state intercalations of Mg, Ni, and Cu into Mo3Sb7

2003 ◽  
Vol 81 (11) ◽  
pp. 1157-1163 ◽  
Author(s):  
N Soheilnia ◽  
E Dashjav ◽  
H Kleinke

Mo3Sb7 was synthesized by heating the elements in the stoichiometric ratio in a sealed silica tube at 700 °C. The title compounds AδMo3Sb7 (A = Mg, Ni, Cu) were prepared by annealing prereacted Mo3Sb7 with different amounts of A in powder form between 500 and 750 °C. According to our single-crystal structure studies, the A atoms can be intercalated in small amounts into the cubic voids of the Mo3Sb7 structure without noticeable symmetry changes (space group Im[Formula: see text]m). The different cations cause different band-gap decreases that depend on the element as well as its concentration.Key words: thermoelectrics, band-gap tuning, intercalation, antimonide, electronic structure.

2014 ◽  
Vol 69 (7) ◽  
pp. 839-843 ◽  
Author(s):  
Guido D. Frey ◽  
Wolfgang W. Schoeller ◽  
Eberhardt Herdtweck

The crystal structure of 1-(1H-pyrazol-4-yl)ethanone (commonly known as 4-acetylpyrazole; C5H6N2O) was determined from single-crystal X-ray data at 173 K: monoclinic, space group P21/n (no. 14), a = 3.865(1), b = 5.155(1), c = 26.105(8) Å, β = 91.13(1)°, V = 520.0(2) Å3 and Z = 4. The adjacent molecules assemble into a wave-like ribbon structure in the solid state, linked by strong intermolecular N-H...N hydrogen bonds between the pyrazole rings and a weak C-H...O=C hydrogen bond involving the carbonyl group. The ribbons are stacked in the solid state via weak π interactions between the pyrazole rings.


2013 ◽  
Vol 69 (12) ◽  
pp. i84-i84 ◽  
Author(s):  
Aicha Mbarek ◽  
Fadhila Edhokkar

The crystal structure of strontium diarsenate has been reinvestigated from single-crystal X-ray diffraction data. In contrast to the previous determinations of this structure [Weilet al.(2009).Solid State Sci.11, 2111–2117; Edhokkaret al.(2012).Mater. Sci. Eng.,28, 012017] and to all isotypicA2B2O7compounds that crystallize in the space groupP41, the current redetermination revealed theP43enantiomorph of Sr2As2O7with a purity of 96.3 (8)%. The crystal structure is made up from two eclipsed As2O7diarsenate groups (symmetry 1) with characteristically longer As—O bridging bonds [1.756 (4)–1.781 (4) Å] than the terminal As—O bonds [1.636 (4)–1.679 (4) Å] and four Sr2+sites with coordination numbers ranging from seven to nine. The building units are arranged in sheets parallel to (001).


2007 ◽  
Vol 62 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Nachiappan Arumugam ◽  
Eva-Maria Peters ◽  
Martin Jansen

A new potassium molybdenum oxide, K6Mo10O33, was synthesized by solid state reaction from the appropriate quantities of pre-dried MoO3 and K2MoO4, fired at around 650 °C for 2 d. The structure has been solved by using single crystal X-ray diffraction. The compound adopts the space group P1, with the lattice constants a = 7.7100(5), b = 11.9659(8), c = 17.1321(12) A° , α = 86.42 (10), β = 77.18(10), γ = 74.14(10)°. The structure is built up of infinite chains of edge-sharing MoO6 octahedra and groups of four MoO6 octahedra forming Mo4O17 units. These sub-units are connected together by common vertices.


2003 ◽  
Vol 59 (4) ◽  
pp. 472-478 ◽  
Author(s):  
P. Gougeon ◽  
P. Gall ◽  
J.-F. Halet ◽  
R. Gautier

The crystal structures of the rare-earth members of the series RMo5O8 (R = Ce to Eu) have been investigated and compared with those of the La and Gd members previously published in order to understand the influences of the size and the charge of the cation on the different Mo—Mo bonds. The RMo5O8 compounds crystallize in the monoclinic space group P21/c. Their crystal structure is characterized by bioctahedral Mo10 clusters forming extended chains. The results of our single-crystal studies show that the modification of charge predominantly affects the Mo—Mo bonds between the Mo10 clusters and, to a lesser extent, the intra-cluster distances, while the cationic size induces only small variations. Theoretical investigations confirm this statement and allow the understanding of the bonding mode in these compounds.


1995 ◽  
Vol 48 (7) ◽  
pp. 1373 ◽  
Author(s):  
AT Baker ◽  
DC Craig ◽  
AD Rae

The crystal structure of bis (2,2′:6′,2″-terpyridine)nickel(II) bis (perchlorate) hydrate has been determined by single-crystal X-ray diffractometry . The compound is monoclinic, space group P21, with two molecules in a unit cell of dimensions a 8.827(4), b 8.910(2), c 20.148(9) Ǻ, β 98.71(2)°. The structure was refined by least-squares to a residual of 0.065 for 2184 observed reflections. The compound is found to be isomorphic with the iron(II) analogue previously reported: the cation has approximate D2d symmetry, with the main distortion from octahedral symmetry being an axial compression. Both the solid state reflectance and solution spectra have been measured and some significant differences are noted.


1996 ◽  
Vol 51 (7) ◽  
pp. 917-921 ◽  
Author(s):  
D. Trinschek ◽  
M. Jansen

A new modification of Na2Zn2O3 has been synthesized via solid state reaction. According to the single crystal structure determination, the compound crystallizes in the space group P43212 (No. 96) with lattice parameters a = 6.1812(2), c = 9.4479(4) Å, Z = 4. The structure consists of ZnO4 tetrahedra connected via edges and corners forming a threedimensional network. The structure can be described as an distorted anti spinel.


Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group


1997 ◽  
Vol 52 (5) ◽  
pp. 663-668 ◽  
Author(s):  
B. Mertens ◽  
Hk. Müller-Buschbaum

Abstract Single crystals of I RbCd4V3O12 and TlCd4V3O12 II have been prepared by solid state reactions in closed iron tubes. The compounds crystallize closely related to the Johillerite structure in the space group C62h- C2/c with I: a = 13.058(3); b - 13.528(3), c = 7 .0 6 0 (2 )Å , β = 114.88(2)°; II: a = 12.999(6), b = 13.527(7), c = 7.055(3) Å , β = 114.88(4)°, Z = 4. Special features are the loss of Cu2+ in order to gain an additional Cd2+ position. The crystal structure is discussed with respect to related compounds of the Johillerite type.


2020 ◽  
Vol 75 (8) ◽  
pp. 765-768
Author(s):  
Bohdana Belan ◽  
Dorota Kowalska ◽  
Mariya Dzevenko ◽  
Mykola Manyako ◽  
Roman Gladyshevskii

AbstractThe crystal structure of the phase Ce5AgxGe4−x (x = 0.1−1.08) has been determined using single-crystal X-ray diffraction data for Ce5Ag0.1Ge3.9. This phase is isotypic with Sm5Ge4: space group Pnma (No. 62), Pearson code oP36, Z = 4, a = 7.9632(2), b = 15.2693(5), c = 8.0803(2) Å; R1 = 0.0261, wR2 = 0.0460, 1428 F2 values and 48 variables. The two crystallographic positions 8d and 4c show Ge/Ag mixing, leading to a slight increase in the lattice parameters as compared to those of the pure binary compound Ce5Ge4.


2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.


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