Sunday 24 March 2019

Education sites

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https://youtu.be/KK2aXtjdLYg
(Chemcore Academy)


*_SOME USEFUL  WEBSITES  ONLINE EDUCATIONAL SUPPORT_*

https://youtu.be/KK2aXtjdLYg (Chemcore Academy)
www.khanacademy.org
www.academicearths.org
www.coursera.com
www.edx.org
www.open2study.com
www.academicjournals.org
codeacademy.org
youtube.com/education

*BOOK SITES*
www.bookboon.com
http://ebookee.org
http://sharebookfree.com
http://m.freebooks.com
www.obooko.com
www.manybooks.net
www.epubbud.com
www.bookyards.com
www.getfreeebooks.com
http://freecomputerbooks.com
www.essays.se
www.sparknotes.com
www.pink.monkey.com

*ONLINE EDUCATIONAL SUPPORT*
http://www.ocwconsortium.org/
http://www.ocwconsortium.org/en/courses/ocwsites
http://ocw.tufts.edu -Tuft University
http://ocw.upm.es -Univesidad Politechnica, Madrid
http://www.open.edu/openlearn/
http://ocw.usu.edu/ -Utah State University
http://open.umich.edu/ -University of Michigan
http://ocw.nd.edu/ -Nore Dame University

*ANSWERS TO QUESTIONS*
www.ehow.com
www.whatis.com
www.howstuffwork.com
www.webopedia.com
www.plagtracker.com
www.answers.com

*SEARCH SITES*
■ About.com (www.about.com)
■ AllTheWeb (www.alltheweb.com)
■ AltaVista (www.altavista.com)
■ Ask Jeeves! (www.askjeeves.com)
■ Excite (www.excite.com)
■ HotBot (www.hotbot.com)
■ LookSmart (www.looksmart.com)
■ Lycos (www.lycos.com)
■ Open Directory (www.dmoz.org)
■ Google (www.google.com)
■ Mamma (www.mamma.com)
■ Webcrawler (www.webcrawler.com)
■ Aol (www.aol.com)
■ Dogpile (www.dogpile.com)
■ 10pht (www.10pht.com)

*SEARCHING FOR PEOPLE*
■ AnyWho (www.anywho.com)
■ InfoSpace (www.infospace.com)
■ Switchboard (www.switchboard.com)
■ WhitePages.com (www.whitepages.com)
■ WhoWhere (www.whowhere.lycos.com)

*SEARCHING FOR THE LATEST NEWS*
■ ABC News (www.abcnews.com)
■ CBS News (www.cbsnews.com)
■ CNN (www.cnn.com)
■ Fox News (www.foxnews.com)
■ MSNBC (www.msnbc.com)
■ New York Times (www.nytimes.com)
■ USA Today (www.usatoday.com)

*SEARCHING FOR SPORTS HEADLINES AND SCORES*
■ CBS SportsLine (www.sportsline.com)
■ CNN/Sports Illustrated (sportsillustrated.cnn.com)
■ ESPN.com (espn.go.com)
■ FOXSports (foxsports.lycos.com)
■ NBC Sports (www.nbcsports.com)
■ The Sporting News (www.sportingnews.com)

*SEARCHING FOR MEDICAL INFORMATION*
■ healthAtoZ.com (www.healthatoz.com)
■ kidsDoctor (www.kidsdoctor.com)
■ MedExplorer (www.medexplorer.com)
■ MedicineNet (www.medicinenet.com)
■ National Library of Medicine
(www.nlm.nih.gov)
■ Planet Wellness (www.planetwellness.com)
■ WebMD Health (my.webmd.com)

*JOURNALS*
http://www.indexcopernicus.com Multidisciplinary
http://www.ajol.info/ - African Journal Online
www.africanjournalseries.com -
www.devconsortservices.com.ng
www.doaj.org - directory of open access journal
www.sabinet.co.za - South African Journals.
www.oajse.com - Open Access Journal Search Engine
http://www.lub.lu.se/en.html - Lund University
http://www.dovepress.com/ - Free Scientific & Medical Materials
http://www.copernicus.org/ - Access & Publication

ACADEMIC SEARCH/WEB RESEARCH TOOLS/REFERENCE MANAGERS
http://academic.research.microsoft.com - Multidisciplinary
http://www.scirus.com
www.scholar.google.com
http://dbis.uni-trier.de/DBL-Browser/ - Digital Bibliography Library Browser
http://academic.live.com - Live Search Academic
http://www.science.gov/ - USA government for Science
http://citeseerx.ist.psu.edu/index - Computing & Information Sciences
http://www.mendeley.com/ - academic social network/collaboration
http://www.worldcat.org/ - Multidisciplinary
http://libserver.cedefop.europa.eu - Voc & Tech Education
http://inspirehep.net/ - Stanford physics information retrieval system

Monday 11 March 2019

why NiCl4 is tetrahedral but PtCl4 is square planar? co-ordination chemistry

The two main factors that differentiate the Ni(II) complex from the Pd(II) complex are therefore:
  1. The orbitals of PdX2+ are more radially diffuse (i.e. bigger) and therefore form stronger overlap with the orbitals on ClX, as compared to the orbitals of NiX2+. This leads to larger splitting of the d orbitals - or the relevant MOs (I'm too lazy to check their symmetry labels) - and hence a larger Î”E.
  2. Again because the orbitals are more diffuse, the pairing energy  is smaller in the palladium complex (it basically costs less energy to stuff them into the same orbital).
Together, these two factors ensure that practically all  and   MLX4 complexes adopt a square planar geometry, even if the ligand is not a strong-field ligand. Other examples of such square planar complexes are [PtClX4]X2 and [AuClX4]X.
In fact,  same factors also cause the octahedral complexes to be almost invariably low-spin. For example, the  complex [Fe(ox)X3]X3 has five unpaired electrons, indicating a high-spin configuration, (t2g)3(eg)2. However, [Ru(ox)X3]X3 has one unpaired electron, which implies a low-spin configuration (t2g)5.

ANCIENT SCIENCE

  https://www.youtube.com/watch?v=1eetRjqkUkQ&list=PLuR244LTfD1Dlu2JBzy6yKTCU1DBJv6oy&index=5 https://youtu.be/1eetRjqkUkQ