トポロジカル対化学のオーダーリングは,ネットワークグラスで,中間の長さや長さのスケールでオーダーされます
Philip S Salmon1, Richard A Martin, Philip E Mason
1Department of Physics, University of Bath, Bath BA2 7AY, UK. p.s.salmon@bath.ac.uk
Nature
|May 6, 2005
まとめ
ネットワークグラスの原子順序は,ガラスの亜鉛塩化物 (ZnCl2) の中性子 difraktion を用いて研究されました. 研究は,これらの材料の最も近い隣人を超えるオーダーリングを規定する2つの異なる長さスケールを明らかにしました.
科学分野:
- マテリアルサイエンス 材料科学
- 凝縮物質物理学 凝縮物質物理学
- 固体化学 固体化学
背景:
- 最寄りの隣人相互作用を超えたネットワークグラスの原子順序は,議論の余地のある話題です.
- ガラスネットワークの性質と形成を理解するには,詳細な実験データが必要です.
研究 の 目的:
- 構造的に無秩序なAX2システムにおけるトポロジカルおよび化学的順序を調査する.
- ニュートロン difraktion で,ガラスの亜鉛塩化物 (ZnCl2) に同位素置換を適用する.
主な方法:
- 同位体置換による中性子 difraktion を利用しました.
- 分析したガラスのZnCl2は,ガラスを形成するプロトタイプのイオンネットワークとして.
- 比較のために,ガラスの GeSe2 を調べました.
主要な成果:
- ガラスのZnCl2.2の最も近い隣人を越えてオーダーするための2つの長さスケールを特定しました.
- 1.09(3) A(-1) で最初の鋭い difraktion ピークが観察され,中間の範囲の順序を示しています.
- 62(4) Aまでのオーダーが検出され,拡張範囲のオーダーを意味しています.
- これらのオーダーリングの特徴は,ガラスの GeSe2.2 にも存在することを確認しました.
結論:
- ネットワークグラスのトポロジカルおよび化学的順序は,中間および延長された長さスケールの両方で発生します.
- この発見は,超冷却液体とガラスの現象学に関する構造的洞察を提供します.
- この研究は,ネットワークを形成するガラスの長距離原子の配列を明らかにしている.
関連する概念動画
02:54Trends in Lattice Energy: Ion Size and Charge
23.4K
An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure of the strength of this attraction. The lattice energy (ΔHlattice) of an ionic compound is defined as the energy required to separate one mole of the solid into its component gaseous ions. For the ionic solid sodium chloride, the lattice energy is the enthalpy change of the process:
23.4K
02:37Metallic Solids
16.5K
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and...
16.5K
02:18Network Covalent Solids
12.9K
Network covalent solids contain a three-dimensional network of covalently bonded atoms as found in the crystal structures of nonmetals like diamond, graphite, silicon, and some covalent compounds, such as silicon dioxide (sand) and silicon carbide (carborundum, the abrasive on sandpaper). Many minerals have networks of covalent bonds.
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
12.9K
02:52Stereoisomerism
11.1K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
11.1K
02:58Crystal Field Theory - Octahedral Complexes
28.5K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
28.5K
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.3K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.3K