scholarly journals Understanding ring strain and ring flexibility in six- and eight-membered cyclic organometallic group 14 oxides

2006 ◽  
Vol 761 (1-3) ◽  
pp. 177-193 ◽  
Author(s):  
Jens Beckmann ◽  
Dainis Dakternieks ◽  
Allan E.K. Lim ◽  
Kieran F. Lim ◽  
Klaus Jurkschat
Keyword(s):  
Group 14 ◽  
Ring Strain ◽  
Organometallic Group

Structure and spectroscopic properties of porphyrinato group 14 derivatives: Part I – Phenylacetylido ligands

2017 ◽  
Vol 72 (11) ◽  
pp. 801-811 ◽  
Author(s):  
Stefan Stadlbauer ◽  
Roland Fischer ◽  
Michaela Flock ◽  
Peter W. Zach ◽  
Sergey M. Borisov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Electron Pair ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Properties ◽  
Group 14 ◽  
Functional Theory ◽  
Structure Determinations ◽  
Fluorescence And Phosphorescence ◽  
Organometallic Group

AbstractA series of bis(phenylacetylido)(porphyrinato) E(IV) (E=Si, Ge, Sn) derivatives were obtained by reacting lithium phenylacetylide with the corresponding bis(chlorido)(porphyrinato) E(IV) precursors. Crystal structure determinations demonstrated that the trans-coordinated acetylide ligands deviate from their expected ideal geometry. Density functional theory calculations and comparison of the packing of the molecules among the homologous series of Si(IV), Ge(IV) and Sn(IV) revealed causes for the deviation from the simple valence shell electron pair repulsion model. Fluorescence and phosphorescence of these organometallic group 14 derivatives were studied and the results are compared to the literature-known properties of the related bis(chlorido)(porphyrinato) E(IV) compounds (E=Si, Ge, Sn). The first crystal structure of a porphyrinato Ge(IV) compound with σ-bonded acetylide ligands is reported.

A Tem Study of Slip Systems in MoSi2/WSi2 Alloys

1991 ◽  
Vol 49 ◽  
pp. 942-943
Author(s):  
Stuart A. Maloy
Keyword(s):  
Solid Solution ◽  
Solid Solution Hardening ◽  
Slip Systems ◽  
High Melting ◽  
Group 14 ◽  
Solution Hardening ◽  
Brittle To Ductile Transition ◽  
High Melting Temperature ◽  
Tetragonal Unit Cell ◽  
Structural Applications

MoSi2 has recently been investigated as a potential material for high temperature structural applications. It has excellent oxidation resistance up to 1700°C, a high melting temperature, 2030°C, and a brittle-to-ductile transition temperature at 900-1000°C. WSi2 is isomorphous with MoSi2 and has a body-centered tetragonal unit cell of the space group 14/mmm. The lattice parameters are a=3.20 Å and c=7.84 Å for MoSi2 and a=3.21 Å and c=7.88 Å for WSi2. Therefore, WSi2 was added to MoSi2 to improve its strength via solid solution hardening. The purpose of this study was to investigate the slip systems in polycrystalline MoSi2/WSi2 alloys.

Hearing Outcome of Stapes Surgery in NIENT, Bangladesh

2020 ◽  
Vol 26 (1) ◽  
pp. 31-36
Author(s):  
Md Zakaria Sarkar ◽  
AHM Ferdows Nur ◽  
Utpal Kumar Dutta ◽  
Muhammad Rafiqul Islam ◽  
Debabrota Roy ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cross Sectional Study ◽  
Surgical Trauma ◽  
Group 14 ◽  
Progressive Hearing Loss ◽  
Cross Sectional ◽  
Hearing Gain ◽  
Hearing Outcome

Objective: The aim of this study was to evaluate hearing outcome after stapedotomy in patients with Otosclerosis. Methods: This cross sectional study was carried out from July 2017 to January 2019 in National Institute of ENT, Unit V. About 22 patients with Otosclerosis were included in this study. Diagnosis of Otosclerosis was based on the history, medical status with Otoscopy, Tuning fork tests and Audiometric tests. We compiled data on the pre and post operative air-bone gap (ABG) at 0.5, 1, 2 KHZ. The ABG was Calculated using AC and BC thresholds on the same audiogram. Post operative hearing gain was then Calculated from the ABG before the operation minus the ABG of the last follow up examination Results: In this study most of the cases were age group 14-30 years (72.7%), female (54.5%). Most common symptoms was progressive hearing loss, tinnitus (77.8%).The average preoperative hearing loss in this study was (AC) was 48.31±7.68. The average post opt. hearing (AC) at follow up was 28.95±10.30 with an average hearing gain of 15.40±8.53 dB which was significant. The average pre-operative ABG was 28.99 dB ± 8.10. The average post opt. ABG was analyzed at 1 follow up showed ABG 13.18±8.09 dB which was found to be significant. Conclusion: Stapedotomy is an effective surgical procedure for the treatment of otosclerosis which leads to improvement in patient’s quality of life. A favorable hearing outcome can be obtained by the combination of experienced hands with minimal surgical trauma and appropriate surgical technique. Bangladesh J Otorhinolaryngol; April 2020; 26(1): 31-36

Bond-length distributions for ions bonded to oxygen: Results for the non-metals and discussion of lone-pair stereoactivity and the polymerization of PO4

2017 ◽  
Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne
Keyword(s):  
Metal Ions ◽  
Bond Length ◽  
Lone Pair ◽  
Group 14 ◽  
Oxygen Lone Pair

Bond-length distributions are examined for three configurations of the H+ ion, sixteen configurations of the group 14-16 non-metal ions and seven configurations of the group 17 ions bonded to oxygen. Lone-pair stereoactivity for ions bonded to O<sup>2-</sup> is discussed, as well as the polymerization of the PO<sub>4</sub> group.

To Bend or Not to Bend, the Dilemma of Multiple Bonds

2019 ◽  
Author(s):  
Michele Pizzocchero ◽  
Matteo Bonfanti ◽  
Rocco Martinazzo
Keyword(s):  
First Principles ◽  
2D Materials ◽  
Main Group ◽  
First Principles Calculations ◽  
Group 14 ◽  
Multiple Bonds ◽  
Main Group Elements ◽  
Structural Distortions

The manuscript addresses the issue of the structural distortions occurring at multiple bonds between high main group elements, focusing on group 14. These distortions are known as trans-bending in silenes, disilenes and higher group analogues, and buckling in 2D materials likes silicene and germanene. A simple but correlated \sigma + \pi model is developed and validated with first-principles calculations, and used to explain the different behaviour of second- and higher- row elements.

Recent Advances in Group 14 Cross-Coupling: Si and Ge-Based Alternatives to the Stille Reaction

2004 ◽  
Vol 1 (3) ◽  
pp. 211-226 ◽  
Author(s):  
Alan Spivey ◽  
Christopher Gripton ◽  
Joseph Hannah
Keyword(s):  
Cross Coupling ◽  
Stille Reaction ◽  
Group 14 ◽  
Recent Advances

ChemInform Abstract: Activation of Phosphorus by Group 14 Elements in Low Oxidation States.

ChemInform ◽  
2012 ◽  
Vol 43 (23) ◽  
pp. no-no
Author(s):  
Shabana Khan ◽  
Sakya S. Sen ◽  
Herbert W. Roesky
Keyword(s):  
Oxidation States ◽  
Group 14 ◽  
Group 14 Elements

(thf)2Ln(Ge9{Si(SiMe3)3}3)2 (Ln = Eu, Sm): the first coordination of metalloid germanium clusters to lanthanides

2021 ◽  
Author(s):  
Andreas Schnepf ◽  
Svetlana Klementyeva ◽  
Claudio Schrenk ◽  
Marat M Khusniyarov ◽  
Minghui Zhang
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Crystallographic Analysis ◽  
Rare Earth Complexes ◽  
Group 14 ◽  
X Ray ◽  
Germanium Clusters

We report the synthesis, structure and magnetic properties of the first rare earth complexes of metalloid group 14 clusters [(thf)2Ln(Ge9Hyp3)2] (Ln = Eu, Sm, Hyp = Si(SiMe3)3). X-ray crystallographic analysis...

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