Stannide

A stannide can refer to an intermetallic compound containing tin combined with one or more other metals; an anion consisting solely of tin atoms or a compound containing such an anion, or, in the field of organometallic chemistry an ionic compound containing an organotin anion (e.g.see[1] an alternative name for such a compound is stannanide.)

Binary alkali and alkaline earth stannides

When tin is combined with an alkali or alkaline earth metal some of the compounds formed have ionic structures containing monatomic or polyatomic tin anions (Zintl ions), such as Sn4− in Mg2Sn[2] or Sn4−
9 in K4Sn9.[3] Even with these metals not all of the compounds formed can be considered to be ionic with localised bonding, for example Sr3Sn5, a metallic compound, contains {Sn5} square pyramidal units.[4]

Ternary alkali and alkaline earth stannides

Ternary (where there is an alkali or alkaline earth metal, a transition metal as well as tin e.g. LiRh3Sn5[5] and MgRuSn4[6]) have been investigated.

Other metal stannides

Binary (involving one other metal) and ternary (involving two other metals) intermetallic stannides have been investigated. Niobium stannide, Nb3Sn is perhaps the best known superconducting tin intermetallics. This is more commonly called "niobium-tin".

Stannide ions, Sny−
x

Some examples of stannide Zintl ions are listed below. Some of them contain 2-centre 2-electron bonds (2c-2e), others are "electron deficient" and bonding sometimes can be described using polyhedral skeletal electron pair theory (Wade's rules) where the number of valence electrons contributed by each tin atom is considered to be 2 (the s electrons do not contribute).[7] There are some examples of silicide and plumbide ions with similar structures, for example tetrahedral Si4−
4, the chain anion (Si2−)n, Pb4−
4 and Pb4−
9.[2][8]

  • Sn4− found for example in Mg2Sn.[2]
  • Sn4−
    4    , tetrahedral with 2c-2e bonds e.g. in CsSn.[2]
  • Sn2−
    4    , tetrahedral closo-cluster with 10 electrons (2n + 2).[9]
  • (Sn2−)n zig-zag chain polymeric anion with 2c-2e bonds found for example in BaSn.[2]
  • Sn2−
    5     closo-cluster, 12 electrons (2n + 2), (i.e. trigonal bipyramidal) in (2,2,2-crypt-Na)2Sn5.[10]
  • (Sn4−
    8    )
    n     polymeric two-dimensional anion in NaSn2.[11]
  • Sn4−
    9     nido-cluster 22 electrons (2n + 4), capped square antiprismatic with as per polyhedral skeletal electron pair theory, in the intermetallic K4Sn9,[3] and a distorted ion in the salt Na4Sn9·7 en.[12]
  • Sn3−
    9     a paramagnetic, 21 electrons, closo- cluster anion (D3h symmetry), 1 more electron than the 20 (2n + 2) predicted by polyhedral skeletal electron pair theory.[13]
  • (Sn7−
    12    )
    n     polymeric two-dimensional anion in Na7Sn12[14]

References
  1. Flacke, F.; Jacobs, H. (1997). "[Li(NH3)4] [Sn(SnPh3)3].C6H6, Crystal structure of a stannide with trigonal pyramidal tin skeleton". European journal of solid state and inorganic chemistry. 34 (5): 495–501.
  2. S.M. Kauzlarich,(1994), Zintl Compounds, Encyclopedia of Inorganic Chemistry, John Wiley & sons, ISBN 0-471-93620-0
  3. Hoch, C.; Wendorff, M.; Röhr, C. (2002). "Tetrapotassium nonastannide, K4Sn9". Acta Crystallogr C. 58 (4): i45–i46. doi:10.1107/S0108270102002032. PMID 11932511.
  4. Klem, M. T.; Vaughey, J. T.; Harp, J G.; Corbett, J D. (2001). "A3Tt5 Phases Sr3Sn5, Ba3Pb5, and La3Sn5. Structure and Bonding in a Series of Isotypic Metallic Compounds with Increased Electron Count and Their Comparison with the Nominal Zintl Phase La3In5". Inorg. Chem. 40 (27): 7020–7026. doi:10.1021/ic010804v.
  5. Sreeraj, P; Johrendt, D.; Müller, H.; Hoffmann, R.-D.; Wu, Zhiyun; Pöttgen, R. (2005). "The stannide LiRh3Sn5: Synthesis, structure, and chemical bonding". Zeitschrift für Naturforschung B. 60 (9): 933–939. doi:10.1515/znb-2005-0904.
  6. Schlüter, M.; Kunst, A.; Pöttgen, R. (2002). "The Ternary Stannides MgRuSn4 and MgxRh3Sn7−x (x = 0.98–1.55)". Zeitschrift für anorganische und allgemeine Chemie. 628 (12): 2641–2646. doi:10.1002/1521-3749(200212)628:12<2641::aid-zaac2641>3.0.co;2-y.
  7. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  8. Yong, Li; Stephan D. Hoffmann; Thomas F. Fässler (1 December 2006). "A low-dimensional arrangement of [Pb9]4− clusters in [K(18-crown-6)]2K2Pb9·(en)1.5". Inorganica Chimica Acta. Elsevier. 359 (15): 4774–4778. doi:10.1016/j.ica.2006.04.017.
  9. Critchlow, S. C.; Corbett, J. D. (1981). "Stable homopolyatomic anions: the tetrastannide (2–) and tetragermanide(2–) anions, Sn2−
    4     and Ge2−
    4     X-ray crystal structure of [K+(crypt)]
    2    Sn2−
    4    . ethylenediamine". J. Chem. Soc. Chem. Commun. 1981 (5): 236–237. doi:10.1039/C39810000236.
  10. Edwards, P. A.; Corbett, J. D. (1977). "Stable homopolyatomic anions. Synthesis and crystal structures of salts containing the pentaplumbide(2−) and pentastannide(2−) anions". Inorg. Chem. 16 (4): 903–907. doi:10.1021/ic50170a036.
  11. Dubois, F.; Schreyer, M.; Fässler, T. F. (2005). "NaSn2: A Novel Binary Zintl Phase with 2D Polyanions of Realgar-Type Units [Sn8]4−". Inorg. Chem. 44 (3): 477–479. doi:10.1021/ic048770p.
  12. Diehl, L.; Khodadadeh, K.; Kummer, D.; Strähle, J. (1976). "Anorganische Polyederverbindungen, III. Zintl's Polyanionige Salze: Darstellung und Eigenschaften der kristallinen Verbindungen [Na4·7 en]Sn9, [Na4·5 en]Ge9 und [Na3·4 en]Sb7 und ihrer Lösungen Die Kristallstruktur von [Na4·7 en]Sn9". Chemische Berichte. 109 (100): 3404–3418. doi:10.1002/cber.19761091018.
  13. Critchlow, S. C.; Corbett, J. D. (1983). "Homopolyatomic anions. The synthesis and characterization of the novel paramagnetic nonastannide(3−) anion Sn3−
    9    , a D3h cluster with 21 skeletal electrons". J. Am. Chem. Soc. 105 (17): 5715–5716. doi:10.1021/ja00355a045.
  14. .Fässler, T.F.; Hoffmann, S. (2003). "Na7Sn12: A Binary Zintl Phase with a Two-Dimensional Covalently Bonded Tin Framework". Inorg. Chem. 42 (18): 5474–5476. doi:10.1021/ic030148u.
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