نتایج جستجو برای: atom bond connectivity index

تعداد نتایج: 571151  

2012
Consiglia Tedesco Marina Lamberti Mina Mazzeo

In the title compound, [Ni(C24H36P3)Cl], the Ni(II) atom adopts a distorted square-planar geometry with the two neutral P atoms of the tridentate ligand trans to one another. Bond lengths and angles of the phosphide P atom feature a pyramidal geometry of the donor atom, which forms a single bond with the Ni(II) atom, retaining a stereochemically active lone pair.

Journal: :Acta crystallographica. Section B, Structural science 2004
Daniel E Lynch Glyn D Jones

The geometry of the R2(2)(8) graph set formed between a 2-aminoheterocyclic ring containing an Nsp2 atom (in the 1-position of the ring) and a carboxylic acid has been studied. Collating data from known co-crystal structures containing five- and six-membered heterocyclic rings from the Cambridge Structural Database revealed unexpected differences between two kinds of non-hydrogen contact distan...

Journal: :Journal of Molecular Liquids 2023

The hydrogen-bonded structure of methanol – water mixtures is investigated over the entire alcohol concentration range (from xMethanol = 0.1 to 1.0) at several temperatures, from 300 K down freezing point given mixture. Classical molecular dynamics simulations have been carried out, using all-atom OPLS-AA force field for and TIP4P/2005 model molecules. Simulation trajectories (‘particle configu...

2012
Tzvetalin S. Vassilev

In this talk we consider some results and open problems from the Chemical Graph Theory, mainly concerning structural indices/properties. The Atom Bond Connectivity index, also known as ABC index was defined by Estrada [4] with relation to the energy of formation of alkanes. It was quickly recognized that this index reflects important structural properties of graphs in general. The ABC index was...

2012
Akbar Raissi Shabari Fahimeh Sabbaghi Mehrdad Pourayoubi Marek Nečas Michal Babiak

The P atom in the title compound, C(16)H(20)NO(2)PS, is bonded in a distorted tetra-hedral P(S)(O)(2)N environment with the bond angles at the P atom in the range 99.37 (7) to 115.68 (5)°. The angles at the amido N atom (with bond-angle sum of 357.8°) confirm its sp(2) character. The C-O-P bond angles are 119.78 (11) and 119.39 (12)°.

Journal: :transactions on combinatorics 2013
buzohragul eskender elkin vumar

let $g=(v,e)$ be a connected graph. the eccentric connectivity index of $g$, $xi^{c}(g)$, is defined as $xi^{c}(g)=sum_{vin v(g)}deg(v)ec(v)$, where $deg(v)$ is the degree of a vertex $v$ and $ec(v)$ is its eccentricity. the eccentric distance sum of $g$ is defined as $xi^{d}(g)=sum_{vin v(g)}ec(v)d(v)$, where $d(v)=sum_{uin v(g)}d_{g}(u,v)$ and $d_{g}(u,v)$ is the distance between $u$ and $v$ ...

N. ARIF R. HASNI

The m-order connectivity index (G) m of a graph G is     1 2 1 1 2 1 ... ... 1 ( ) i i im m v v v i i i m d d d  G where 1 2 1 ... i i im d d d  runs over all paths of length m in G and i d denotes the degree of vertex i v . Also,        1 2 1 1 2 1 ... ... 1 ( ) i i im m v v v i i i ms d d d X G is its m-sum connectivity index. A dendrimer is an artificially manufactured or synth...

Journal: :Eur. J. Comb. 2011
Zdenek Dvorak Bernard Lidický Riste Skrekovski

The Randić index R(G) of a nontrivial connected graph G is defined as the sum of the weights (d(u)d(v))− 1 2 over all edges e = uv ofG. We prove that R(G) ≥ d(G)/2, where d(G) is the diameter of G. This immediately implies that R(G) ≥ r(G)/2, which is the closest result to the well-known Grafiti conjecture R(G) ≥ r(G) − 1 of Fajtlowicz [4], where r(G) is the radius of G. Asymptotically, our res...

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