Sulfidostannates, or thiostannates are chemical compounds containing

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...

s composed of

tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored 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, a bar of tin makes a sound, the ...

linked with

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

. They can be considered as

stannate In chemistry, the term stannate or tinnate refers to compounds of tin (Sn). Stannic acid (Sn(OH)4), the formal precursor to stannates, does not exist and is actually a hydrate of SnO2. The term is also used in naming conventions as a suffix; for ...

s with sulfur substituting for oxygen. Related compounds include the

thiosilicate In chemistry and materials science, thiosilicate refers to materials containing anions of the formula . Derivatives where some sulfide is replaced by oxide are also called thiosilicates, examples being materials derived from the oxohexathiodisilica ...

s, and

thiogermanate Sulfidogermanates or thiogermanates are chemical compounds containing anions with sulfur atoms bound to germanium. They are in the class of chalcogenidotetrelates. Related compounds include thiosilicates, thiostannates, selenidogermanates, tellur ...

s, and by varying the chalcogen: selenostannates, and tellurostannates. Oxothiostannates have oxygen in addition to sulfur. Thiostannates can be classed as chalcogenidometalates, thiometallates, chalcogenidotetrelates, thiotetrelates, and chalcogenidostannates. Tin is almost always in the +4 oxidation state in thiostannates, although a couple of mixed sulfides in the +2 state are known, Some thiostannate minerals are known. In nature the tin can be partly replaced by arsenic, germanium, antimony or indium. Many thiostannate minerals contain copper, silver or lead. In the field of mineralogy, these compound can be termed sulfostannates or sulphostannates. Different cluster anions are known: nS₄sup>4–, nS₃sup>2–, n₂S₅sup>2–, n₂S₆sup>4–, n₂S₇sup>6–, n₂S₈sup>2–, n₃S₇sup>2–, n₄S₉sup>2–, n₅S₁₂sup>4–, or n₄S₁₀sup>4–. The number of sulfur atoms coordinated around the tin atom is most commonly four. However there are also complexes with five or six sulfur atoms surrounding the tin. The behaviour for selenium and tellurium differs as only five selenium or four tellurium atoms can bind to a tin atom. The smaller germanium atom can only accommodate four sulfur atoms. For lead it is hard for it to be in the +4 oxidation state. The SnS_n polyhedrons can be standalone in strongly alkaline conditions, or at higher concentrations or less alkaline can condense together. Polyhedra shapes are

tetrahedron In geometry, a tetrahedron (: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular Face (geometry), faces, six straight Edge (geometry), edges, and four vertex (geometry), vertices. The tet ...

for four,

trigonal bipyramid A triangular bipyramid is a hexahedron with six triangular faces constructed by attaching two tetrahedra face-to-face. The same shape is also known as a triangular dipyramid or trigonal bipyramid. If these tetrahedra are regular, all faces of a t ...

for five, and

octahedron In geometry, an octahedron (: octahedra or octahedrons) is any polyhedron with eight faces. One special case is the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at each vertex. Many types of i ...

for six sulfur atoms. The polyhedra can be connected at a vertex (corner), or at an edge. Where connected at an edge, four membered rings of -SnSSnS- with internal angles close to 90°. n₂S₇sup>6– is corner bridged. Tetrahedra linked by at the corner by a disulfur bridge are unknown. Sn₁₀O₄S₂₀^8- is a supertetrahedron made from 1, 3 and 6 tin atoms connected by oxygen on the interior and sulfur on the surface. For anions with formula Sn_xS_y the condensation ratio c is given by . It can vary from to just below .

Synthesis

The first human production of a thiostannate heated tin oxide with sodium carbonate and sulfur: 2SnO₂ + 2Na₂CO₃ + 9S → 2Na₂SnS₃ + 2CO₂ + 3SO₂ Transition metal complexes may be prepared by crystallisation from the ligand solvent. Copper(II) is normally reduced by sulfide S^2- in thiostannates to copper(I).

Anions

Reactions

Some hydrates are unstable, where water reacts with the sulfide to make

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...

gas.

List

References

{{Sulfides Tin compounds Sulfides