Title Density functional study of low-lying isomers of $SiO_{4}$, $GeO_{4}$ and $CO_{4}$, and their relation to tetrahedral solid phases Author Cabria, I. López, M.J. Alonso, J.A. March, N.H. Faculty/Department Faculty of Sciences. Physics Publication type article Publication 2012 Berlin , 2012 Subject Physics Source (journal) European physical journal : D : atomic, molecular and optical physics. - Berlin Volume/pages 66(2012) :4 , p. 105,1-105,4 ISSN 1434-6060 Article Reference 105 ISI 000304411200008 Carrier E-only publicatie Target language English (eng) Full text (Publishers DOI) Affiliation University of Antwerp Abstract In silica (SiO2) and in most silicates, atomic associations exist with composition SiO4 and a structure with four O atoms in tetrahedral coordination around the Si atom. A similar feature is observed in germania (GeO2) and some solids containing Ge instead of Si, although the number of phases containing GeO4 tetrahedra is smaller. In contrast, and in spite of the fact that C is in the same column of the periodic table as Si and Ge, CO2 is a molecular solid, and crystalline and amorphous phases of CO2 showing CO4 tetrahedra are only obtained under extremely high pressures. We have investigated the relation between free SiO4, GeO4 and CO4 clusters and the tetrahedral associations found in the solids mentioned above. The lowest energy structure of those three free clusters is planar, but they have near-tetrahedral and distorted-tetrahedral isomers. The promotion energy from the planar structure to the distorted tetrahedral is low in SiO4, large in CO4, and intermediate in GeO4. This correlates with the facility to form tetrahedral associations in the solids. E-info https://repository.uantwerpen.be/docman/iruaauth/0889c1/0072056.pdf http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000304411200008&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000304411200008&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 Handle