caa a22 4500 463217551 CHVBK 20180405153201.0 cr unu---uuuuu 170326e20071001xx s 000 0 eng 10.1007/s00269-007-0167-5 doi (NATIONALLICENCE)springer-10.1007/s00269-007-0167-5 Experimental multipole-refined and theoretical charge density study of LiGaSi2O6 clinopyroxene at ambient conditions [Elektronische Daten] [R. Bianchi, A. Forni, F. Cámara, R. Oberti, H. Ohashi] The synthetic LiGaSi2O6 clinopyroxene is monoclinic C2/c at room-T. Its experimental electron density, ρ(r), has been derived starting from accurate room-T single-crystal diffraction data. Topological analysis confirms an intermediate ionic-covalent character for Si-O bonding, as found by previous electron-density studies on other silicates such as diopside, coesite and stishovite. The non-bridging Si-O bonds have more covalent character than the bridging ones. The Ga-O bonds have different bonding characters, the Ga-O2 bond being more covalent than the two Ga-O1 bonds. Li-O bonds are classified as pure closed-shell ionic interactions. Similar to spodumene (LiAlSi2O6), Li has sixfold coordination, but the bond critical points associated to the two longest bonds are characterized by very low electron density values. Similar to what previously found in spodumene and diopside, O···O interactions were detected from the topological analysis of ρ(r), and indicate a cooperative interaction among the lone pairs of neighbouring oxygen atoms. In particular, this kind of interaction has been obtained for the O1···O1 edge shared between two Ga octahedra. Integration over the atomic basins gives net charges of −1.39(10), 2.82(10), 1.91(10) and 0.82(8) e for O (averaged), Si, Ga and Li atoms, respectively. Periodic Hartree-Fock and DFT calculations confirm the results obtained by multipole refinement of the experimental data. Moreover, the theoretical topological properties of the electron density distribution on the Si2O6 group are very similar to those calculated for spodumene. Springer-Verlag, 2007 Clinopyroxene nationallicence Multipole refinement nationallicence First-principles calculations nationallicence Bianchi R. CNR-Istituto di Scienze e Tecnologie Molecolari, via Golgi 19, 20133, Milan, Italy aut Forni A. CNR-Istituto di Scienze e Tecnologie Molecolari, via Golgi 19, 20133, Milan, Italy aut Cámara F. CNR-Istituto di Geoscienze e Georisorse (Sezione di Pavia), via Ferrata 1, 27100, Pavia, Italy aut Oberti R. CNR-Istituto di Geoscienze e Georisorse (Sezione di Pavia), via Ferrata 1, 27100, Pavia, Italy aut Ohashi H. HASHI Institute for Silicate Science Nishinakanobu, 1-9-25 Shinagawa, 142-0054, Tokyo, Japan aut Physics and Chemistry of Minerals Springer-Verlag 34/8(2007-10-01), 519-527 0342-1791 34:8<519 2007 34 269 https://doi.org/10.1007/s00269-007-0167-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00269-007-0167-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bianchi R. CNR-Istituto di Scienze e Tecnologie Molecolari, via Golgi 19, 20133, Milan, Italy aut NATIONALLICENCE 700 1- Forni A. CNR-Istituto di Scienze e Tecnologie Molecolari, via Golgi 19, 20133, Milan, Italy aut NATIONALLICENCE 700 1- Cámara F. CNR-Istituto di Geoscienze e Georisorse (Sezione di Pavia), via Ferrata 1, 27100, Pavia, Italy aut NATIONALLICENCE 700 1- Oberti R. CNR-Istituto di Geoscienze e Georisorse (Sezione di Pavia), via Ferrata 1, 27100, Pavia, Italy aut NATIONALLICENCE 700 1- Ohashi H. HASHI Institute for Silicate Science Nishinakanobu, 1-9-25 Shinagawa, 142-0054, Tokyo, Japan aut NATIONALLICENCE 773 0- Physics and Chemistry of Minerals Springer-Verlag 34/8(2007-10-01), 519-527 0342-1791 34:8<519 2007 34 269 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer