A stannide can refer to an

intermetallic An intermetallic (also called an intermetallic compound, intermetallic alloy, ordered intermetallic alloy, and a long-range-ordered alloy) is a type of metallic alloy that forms an ordered solid-state compound between two or more metallic eleme ...

compound containing

tin Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal. Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...

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 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 The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are al ...

metal some of the compounds formed have ionic structures containing monatomic or polyatomic tin anions ( Zintl ions), such as Sn⁴⁻ in Mg₂SnS.M. Kauzlarich,(1994), Zintl Compounds, Encyclopedia of Inorganic Chemistry, John Wiley & sons, or in K₄Sn₉. 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 square pyramidal units.

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 and MgRuSn₄) 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,

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 In chemistry the polyhedral skeletal electron pair theory (PSEPT) provides electron counting rules useful for predicting the structures of clusters such as borane and carborane clusters. The electron counting rules were originally formulated by ...

(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). There are some examples of

silicide A silicide is a type of chemical compound that combines silicon and a (usually) more electropositive element. Silicon is more electropositive than carbon. Silicides are structurally closer to borides than to carbides. Similar to borides and carb ...

and plumbide ions with similar structures, for example tetrahedral , the chain anion (Si²⁻)_''n'', and . *Sn⁴⁻ found for example in Mg₂Sn. *, tetrahedral with 2c-2e bonds e.g. in CsSn. *, tetrahedral ''closo''-cluster with 10 electrons (2''n'' + 2). *(Sn²⁻)_''n'' zig-zag chain polymeric anion with 2c-2e bonds found for example in BaSn. * ''closo''-cluster, 12 electrons (2''n'' + 2), (i.e. trigonal bipyramidal) in (2,2,2-crypt-Na)₂Sn₅. * polymeric two-dimensional anion in NaSn₂. * ''nido''-cluster 22 electrons (2''n'' + 4), capped square antiprismatic with as per

, in the intermetallic K₄Sn₉, and a distorted ion in the salt Na₄Sn₉·7 en. * a paramagnetic, 21 electrons, ''closo''- cluster anion (D_3h symmetry), 1 more electron than the 20 (2''n'' + 2) predicted by

. * polymeric two-dimensional anion in Na₇Sn₁₂.

References

{{reflist, 30em Tin Intermetallics Anions Cluster chemistry