10.1021/ja806737k.s001 Sung-Jin Kim Sung-Jin Kim Florian Kraus Florian Kraus Thomas F. Fässler Thomas F. Fässler Na<sub>6</sub>ZnSn<sub>2</sub>, Na<sub>4.24</sub>K<sub>1.76(1)</sub>ZnSn<sub>2</sub>, and Na<sub>20</sub>Zn<sub>8</sub>Sn<sub>11</sub>: Three Intermetallic Structures Containing the Linear {Sn−Zn−Sn}<sup>6−</sup> Unit American Chemical Society 2009 structure types band structure calculations Zintl phase LMTO Na 20Zn Na 6ZnSn Na 4.24K alkali metal counterions Compound 3 NBO Intermetallic Structures Containing quantum chemical methods AIM HF Zn 7Sn icosahedra Gaussian 03 Magnetic susceptibility measurements show theory level ELF calculations isovalent CO 2 2009-02-04 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Na_sub_6_sub_ZnSn_sub_2_sub_Na_sub_4_24_sub_K_sub_1_76_1_sub_ZnSn_sub_2_sub_and_Na_sub_20_sub_Zn_sub_8_sub_Sn_sub_11_sub_Three_Intermetallic_Structures_Containing_the_Linear_Sn_Zn_Sn_sup_6_sup_Unit/2881375 The novel intermetallic compounds Na<sub>6</sub>ZnSn<sub>2</sub> (<b>1</b>), Na<sub>4.24</sub>K<sub>1.76(1)</sub>ZnSn<sub>2</sub> (<b>2</b>), and Na<sub>20</sub>Zn<sub>8</sub>Sn<sub>11</sub> (<b>3</b>) were obtained from direct fusion of the pure elements, and their structures were determined by single crystal X-ray diffraction. All three compounds adopt new structure types and contain linear anionic {Sn−Zn−Sn}<sup>6−</sup> units with rather short Zn−Sn contacts (2.55−2.58 Å), separated by alkali metal counterions. Compound <b>3</b> comprises layers of interconnected heteroatomic {Zn<sub>7</sub>Sn<sub>5</sub>} icosahedra as an additional unique structural motif. The bonding situation in this 16 valence-electron anion is analyzed by quantum chemical methods. The results of NBO, AIM, and ELF calculations (Gaussian03 on HF/3−21G level) reveal covalent bonding between Sn and Zn. The relationship to isovalent CO<sub>2</sub> is discussed. Band structure calculations on the density functional theory level (LMTO) show that <b>1</b> can be understood as a Zintl phase containing a {Sn−Zn−Sn}<sup>6−</sup> anion; however, Na−Sn contacts must also be considered. Magnetic susceptibility measurements show a temperature-independent, weak diamagnetism for Na<sub>6</sub>ZnSn<sub>2</sub> (<b>1</b>).