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 an alternative name for such a compound is stannanide.) 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 an alternative name for such a compound is stannanide.) 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 or Sn4−9 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 {Sn5} square pyramidal units. 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. 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'. 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). 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.