Icosahedral packing of B12 icosahedra in boron suboxide (B6O)

Hubert, H.; Devouard, Bertrand; Garvie, L. A. J.; O’Keeffe, Michael; Buseck, Peter R.; Petuskey, William T.; McMillan, Paul F.

doi:10.1038/34885

Cited by 249 publications

(225 citation statements)

References 20 publications

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“…Total energies calculated at the relaxed geometries both with siesta 33 and octopus 27 confirm that the tubular structure a is the lowest lying isomer of the B 20 . This is in agreement with the previous findings of Ref.…”

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confidence: 73%

“…7, except for cluster f, which was not considered in Ref. 7 as a low energy candidate for B 20 . This discordance can be attributed to the basis set used in Ref.…”

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confidence: 99%

“…In fact, bulk boron appears in several crystalline and amorphous phases, the best know of which are the α-and β-rombohedral, and the α-tetragonal, also known as low temperature or red boron. In these three phases, boron is arranged in B 12 icosahedra 1, 19,20 (in the α-tetragonal phase these icosahedra are slightly distorted). However, the small clusters appear in four distinct shapes: 16 convex, spherical, quasi-planar, and nanotubular -totally unrelated to the B 12 icosahedra.…”

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confidence: 99%

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The planar-to-tubular structural transition in boron clusters from optical absorption

Marques

Botti

2005

The Journal of Chemical Physics

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The optical response of the lowest energy isomers of the B20 family is calculated using timedependent density functional theory within a real-space, real-time scheme. Significant differences are found among the absorption spectra of the clusters studied. We show that these differences can be easily related to changes in the overall geometry. Optical spectroscopy is thus an efficient tool to characterize the planar to tubular structural transition, known to be present in these boron based systems.PACS numbers: 78.67. Bf, 64.70.Nd, 71.15.Mb For the past years, boron nanostructures have attracted the attention of both theoretical and experimental physicists. This is due to the remarkable properties of boron, that make it an unique element in the periodic table, with important technological applications. 1,2 Boron is characterized by a short covalent radius and has the tendency to form strong and directional chemical bonds. 1,2 These characteristics lead to a large diversity of boron nanostructures -clusters, 3,4,5,6,7 nanowires, 8 and nanotubes 9,10 -that have already been observed.Many experimental studies of small boron-based clusters have been performed in the last decade, namely using mass and photo-electron spectroscopies. 3,4,5,7 However, we still have very limited information regarding the geometries and electronic properties of these systems. From the theoretical point of view, there have been extensive ab initio quantum chemical and density functional calculations about the structural properties of neutral, 3,5,7,11,12,13,14,15,16 cationic, 15,17,18 and anionic clusters. 5,7 The findings were fairly surprising. In fact, bulk boron appears in several crystalline and amorphous phases, the best know of which are the α-and β-rombohedral, and the α-tetragonal, also known as low temperature or red boron. In these three phases, boron is arranged in B 12 icosahedra 1,19,20 (in the α-tetragonal phase these icosahedra are slightly distorted). However, the small clusters appear in four distinct shapes: 16 convex, spherical, quasi-planar, and nanotubular -totally unrelated to the B 12 icosahedra.The most stable members of the B n family with n 20 are known to be planar. 3,5,11,12,13,14,15 Recent calculations showed that B n clusters with n = 24 and n = 32 prefer tubular structures. 16 In a recent study 7 Kiran et al. placed the transition between these two topologies at n = 20. However, their results were not totally conclusive: while the theoretical calculations (using density functional theory at the B3LYP/6-311+G * level) yielded a double ring arrangement as the lowest energy isomer of B 20 and B − 20 , the experimental photo-electron spectra of anionic aggregates of the same size were only compatible with planar structures. Such a incongruity can be explained by the difficulties associated both to the experimental and numerical techniques. Experimentally, the clusters were produced by laser evaporation of a disk target, with the formation of the fragments being mainly controlled by kinematics. The situation is...

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confidence: 73%

“…7, except for cluster f, which was not considered in Ref. 7 as a low energy candidate for B 20 . This discordance can be attributed to the basis set used in Ref.…”

mentioning

confidence: 99%

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confidence: 99%

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The planar-to-tubular structural transition in boron clusters from optical absorption

Marques

Botti

2005

The Journal of Chemical Physics

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“…To the best of our knowledge, it is the first time to perform the first-principles DFT-D calculations of N 2 and CH 4 adsorption on B 12 cluster, α-B 12 and γ-B 28 . Our results demonstrate the adsorption energies of N 2 on these materials are much higher than those of CH 4, which indicates the boron crystals have high selectivity in capturing N 2 from natural gas.…”

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confidence: 99%

Nitrogen removal from natural gas using solid boron: A first-principles computational study

Sun

Wang

et al. 2013

Fuel

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. (2013). Nitrogen removal from natural gas using solid boron: A firstprinciples computational study. Fuel, 109 (2013), 575-581. Nitrogen removal from natural gas using solid boron: A first-principles computational study AbstractSelective separation of nitrogen (N2) from methane (CH4) is highly significant in natural gas purification, and it is very challenging to achieve this because of their nearly identical size (the molecular diameters of N2 and CH4 are 3.64 Å and 3.80 Å, respectively). Here we theoretically study the adsorption of N2 and CH4 on B12 cluster and solid boron surfaces a-B12 and c-B28. Our results show that these electron-deficiency boron materials have higher selectivity in adsorbing and capturing N2 than CH4, which provides very useful information for experimentally exploiting boron materials for natural gas purification.Keywords natural, gas, solid, nitrogen, boron, removal, first, principles, computational, study Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsSun, Q., Wang, M., Li, Z., Li, P., Wang, W., Tan, X. & Du, A. (2013). Nitrogen removal from natural gas using solid boron: A first-principles computational study. Fuel, 109 (2013) AbstractSelective separation of nitrogen (N 2 ) from methane (CH 4 ) is highly significant in natural gas purification, and it is very challenging to achieve this because of their nearly identical size (the molecular diameters of N 2 and CH 4 are 3.64 Å and 3.80 Å, respectively). Here we theoretically study the adsorption of N 2 and CH 4 on B 12 cluster and solid boron surfaces α-B 12 and γ-B 28 . Our results show that these electron-deficiency boron materials have higher selectivity in adsorbing and capturing N 2 than CH 4 , which provides very useful information for experimentally exploiting boron materials for natural gas purification.

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“…2c); pentagonal symmetry is formally forbidden in single crystals but has been observed in in®nitely twinned crystals e.g. B 6 O (Hubert et al, 1998).…”

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confidence: 99%

Separation and crystallization ofT= 3 andT= 4 icosahedral complexes of the hepatitis B virus core protein

Zlotnick

Palmer

Kaufman

et al. 1999

Acta Crystallogr D Biol Crystallogr

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The icosahedral nucleocapsid of human hepatitis B virus is a homopolymer of the dimeric capsid protein also known as hepatitis B core antigen or HBcAg. Puri®ed capsid protein obtained from an Escherichia coli expression system was reassembled into a mixture of T = 3 and T = 4 icosahedral particles consisting of 90 and 120 dimers, respectively. The two types of capsid were separated on a preparative scale by centrifugation through a sucrose gradient. In addition to this heterogeneity, the capsid protein has three cysteines, one of which has a great propensity for forming disul®de bonds between the two subunits, forming a dimer. To eliminate heterogeneity arising from oxidation, alanines were substituted for the cysteines. T = 3 and T = 4 capsids crystallized under similar conditions. Crystals of T = 3 capsids diffracted to $8 A Ê resolution; crystals of T = 4 capsids diffracted to 4 A Ê resolution.

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Icosahedral packing of B12 icosahedra in boron suboxide (B6O)

Cited by 249 publications

References 20 publications

The planar-to-tubular structural transition in boron clusters from optical absorption

The planar-to-tubular structural transition in boron clusters from optical absorption

Nitrogen removal from natural gas using solid boron: A first-principles computational study

Separation and crystallization ofT= 3 andT= 4 icosahedral complexes of the hepatitis B virus core protein

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