ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural-electronic relationships in inorganic solids: powder neutron diffraction studies of the rutile and anatase polymorphs titanium dioxide at 15 295 KJeremy K. Burdett, Timothy Hughbanks, Gordon J. Miller, James W. Richardson Jr., Joseph V. SmithCite this: Am. Chem. Soc. 1987, 109, 12, 3639–3646Publication Date (Print):June 1, 1987Publication History Published online1 May 2002Published inissue 1 June...

A temperature-dependent, single crystal x-ray diffraction study of the giant magnetocaloric material, Gd5(Si2Ge2), across its Curie temperature (276 K) reveals that simultaneous orthorhombic to monoclinic transition occurs by a shear mechanism in which (Si, Ge)-(Si,Ge) dimers are richer Ge increase their distances 0.859(3) and lead twinning. The structural changes electronic structure, provides an atomic-level model for change magnetic behavior with Gd5(SixGe1-x)(4).

The "coloring problem," as applied to the field of solid state chemistry, addresses issues structural preference well distribution different elements within a given structure. Both connectivity and arrangement in affect physical chemical properties, so clear understanding forces controlling how will arrange themselves structure creates ability predict structure-composition-property relationships. There are two fundamental energetic contributions that influence order: site energy bond energy....

Results are presented of single crystal structural, thermodynamic, and reflectivity measurements the double-perovskite Ba2NaOsO6. These characterize material as a 5d^1 ferromagnetic Mott insulator with an ordered moment ~0.2 Bohr magnetons per formula unit TC = 6.8(3) K. The magnetic entropy associated this phase transition is close to Rln2, indicating that quartet groundstate anticipated from consideration structure split, consistent scenario in which ferromagnetism orbital ordering.

The anisotropic physical properties of single crystals orthorhombic PtSn4 are reported for magnetic fields up to 140 kOe, applied parallel and perpendicular the crystallographic b-axis. susceptibility has an approximately temperature independent behavior reveals anisotropy between ac-plane Clear de Haas-van Alphen oscillations in as low 5 kOe at temperatures high 30 K were detected magnetization isotherms. thermoelectric power resistivity show strong field dependencies. A change H = is...

A study of the anisotropy in magnetic, transport, and magnetotransport properties ${\mathrm{FeSb}}_{2}$ has been made on large single crystals grown from Sb flux. Magnetic susceptibility shows diamagnetic to paramagnetic crossover around 100 K. Electrical transport along two axes is semiconducting, whereas third axis exhibits a metal-semiconductor at temperature ${T}_{\mathrm{cr}}$ which sensitive current alignment ranges between 40 80 In $H=70\mathrm{kOe}$ semiconducting restored for...

Composition, crystal structure, and stability of the thermoelectric material, known in literature as "Zn4Sb3", has been characterized using low- room-temperature single-crystal X-ray diffraction techniques, well situ room- high-temperature powder methods. We have found that Zn4Sb3 phase does not exist below 767 K (the β−γ transition temperature); it is Zn6-δSb5 erroneously assigned composition considered to be a promising material. The structure similar "Zn4Sb3" but no Zn/Sb mixture observed...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFragment formalism in main-group solids: applications to aluminum boride (AlB2), calcium silicide (CaAl2Si2), barium-aluminum (BaAl4), and related materialsJeremy K. Burdett Gordon J. MillerCite this: Chem. Mater. 1990, 2, 1, 12–26Publication Date (Print):January 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://pubs.acs.org/doi/10.1021/cm00007a004https://doi.org/10.1021/cm00007a004research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic structure of transition-metal borides with the AlB2 structureJeremy K. Burdett, Enric. Canadell, and Gordon J. MillerCite this: Am. Chem. Soc. 1986, 108, 21, 6561–6568Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://pubs.acs.org/doi/10.1021/ja00281a020https://doi.org/10.1021/ja00281a020research-articleACS PublicationsRequest reuse permissionsArticle...

Temperature and dc magnetic-field dependencies of the electrical resistivity (4.3--300 K, 0--40 kOe) heat capacity (3.5--14 0--100 polycrystalline ${\mathrm{Gd}}_{5}{\mathrm{Ge}}_{4}$ have been measured. The shows a transition between low-temperature metallic high-temperature insulatorlike states at \ensuremath{\sim}130 K. In state both electronic indicate possible presence narrow conduction band. Both low- behaviors correlate with crystallographic magnetic phase transitions induced by...

Composition, crystal structures, polymorphic transformations, and stability of the thermoelectric material known in literature as "Zn4Sb3" have been studied on a polycrystalline sample Bi-flux-grown single crystals using X-ray diffraction techniques, resistance, Seebeck coefficient measurements at various temperatures ranging from 4 to 773 K. Microprobe analysis yields composition flux-grown be close Zn13Sb10, with minor Bi doping. High-temperature studies show that phase is unstable high...

This work presents a detailed, combined experimental and theoretical study on the structural stability of s−p bonded compounds with BaAl4 structure type (space group I4/mmm, Z = 2) as part broad program to investigate complex questions formation atomic arrangements in polar intermetallics. From ab initio calculations employing pseudopotentials plane wave basis set, we extracted optimized parameters, binding energies, electronic systems AeX(III)4, AeX(II)2X(IV)2, AeX(II)2X(III)2 (Ae Ca, Sr,...

The crystal structures, atomic distributions, and theoretical electronic structures of five different Cu5-xZn8+x γ-brass compounds (x = −0.59(3), −0.31(3), 0.00(3), 0.44(3), 0.79(3)) are reported with the goal identifying chemical influences on observed phase width. These have been refined by both neutron X-ray powder diffraction to obtain accurate parameters. All crystallize in space group I4̄3m (No. 217) (Z 4), unit cell parameters a 8.8565(4), 8.8612(5), 8.8664(3) , 8.8745(4), 8.8829(7)...

A crystallographic study and theoretical assessment of the Gd/Y site preferences in Gd 5- x Y Tt 4 ( = Si, Ge) series prepared by high-temperature methods is presented. All structures for Si system belong to orthorhombic, 5Si 4-type (space group Pnma). For Ge system, phases with < 3.6 >or= 4.4 adopt Sm 5Ge structure. composition range <or= 4.2, a monoclinic, U 2Mo 3Si structure P2 1/ c) occurs as majority phase. This type has not been previously observed RE 5 T (T Ge, Ga) differs from known...

The enhanced stability and modified electronic structure of intermetallic compounds provide discovery superior catalysts for chemical conversions with high activity, selectivity, stability. We find that the NaAu2 is an active catalyst CO oxidation at low temperatures. From density functional theory calculations, a reaction mechanism suggested to explain observed barrier by NaAu2, in which molecule reacts directly adsorbed O2 form OOCO* intermediate. presence surface Na increases binding...

Single-phase ${\mathrm{Pr}}_{5}{\mathrm{Ni}}_{1.9}{\mathrm{Si}}_{3}$ and PrNi were prepared characterized by using differential thermal analysis, single crystal, powder x-ray diffraction. Their magnetic properties studied measuring heat capacity as a function of temperature in fields up to 100 kOe magnetization field 50 over the range from 5 400 K. orders magnetically at K, it undergoes second transition 25 As inferred behavior magnetocaloric effect (MCE), both ferromagnetic...

The first-order monoclinic-to-orthorhombic (beta-->gamma) phase transition of the giant magnetocaloric material Gd(5)Si(2)Ge(2) was studied using in situ high-temperature single-crystal X-ray diffraction. A special crystal mounting procedure developed to avoid contamination by oxygen or nitrogen at high temperatures. elastic beta-->gamma transformation occurs 300-320 degrees C during heating, and it is reversible fast slow heating cooling but irreversible rapid cooling. Contrary theoretical...