Polyatomic sulfur ions

Sulfur may be oxidized by different oxidizing agents to yield a variety of polyatomic cations. The currently known species that have been characterized by X-ray diffraction are S, Sg+, and S -, the structures of which are shown in Fig. 16.4.2. 

In crystalline (S4+)(S7l+)4(AsFg 6, the cation S -1- takes the form of a square-planar ring of edge 198 pm. As this is significantly shorter than a typical S-S single bond (206 pm), the S-S bonds in S -1 have some double-bond character. 

In crystalline (S )(AsFg )2, the S cation consists of two seven-membered rings j oined by a five-atom chain. One of the rings has a boat conformation while the other is disordered, existing as a 4 1 mixture of chair and boat conformations. The S-S distances vary greatly from 187 to 239 pm, and S-S-S angles from 91.9° to 127.6°. 

The majority of polysulfide anions have acyclic structures. The configurations of S2 species are in accord with their bond valence (b)  

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Sulfuric acid, on the other hand, is made up of the polyatomic sulfate ion, which has a charge of -2. Because it has a charge of -2, a sulfate ion requires two hydrogen ions (each of which have a charge of+1) to make it stable. Therefore, sulfuric acid is made up of two hydrogen ions and one sulfate ion, and its chemical formula is H2S04. The subscript number two after the symbol for hydrogen... 

There are also some polyatomic ions that end with the letters -ite. S032- and N02 are examples of polyatomic ions with -ite endings. The ion S032- is called a sulfite ion and N02 is a nitrite ion. To name an acid that contains a polyatomic ion that ends in -ite, change the -ite to -ous and add the word acid. Therefore, the name for H2SOs is sulfurous acid and HN02 is nitrous acid. 

Sulfide ions in solution react with sulfur to produce polyatomic anions known as the polysulfides. When... 

Sulfuric acid, H2S04, loses two protons to form what polyatomic ion ... 

Jensen et al. [125] investigated an HPLC/ICP-MS with sulfur-specific detection, as a method for obtaining metabolite profiles for omeprazole administered as 1 1 mixture of 32S- and 34S-labeled material. Analysis based on the monitoring of the chromatographic eluent at either m/z 32 or m/z 34 was not successful due to insufficient sensitivity caused by interferences from polyatomic ions. However, reaction of sulfur with oxygen in the hexapole collision cell, combined with monitoring at m/z 48 (for 32S) or m/z 50 (for 34S), provided a facile method for metabolite profiling. Detection at m/z 48 was superior in sensitivity to detection of m/z 50. 

The charge on a polyatomic ion is equal to the sum of the oxidation numbers for the species present in the ion. For example, the sulfate ion, SO42, has a total charge of -2. This comes from adding the -2 oxidation number for 4 oxygen (total -8) and the +6 oxidation number for sulfur. 

The base ate ions do not always have three oxygen atoms like chlorate does. Consider the polyatomic ions that contain sulfur and oxygen. In this case, the base ion, sulfate, S042-, contains four oxygen atoms. The sulfite ion, S032-, therefore contains three oxygen atoms. 

The prefix "thio" in the name of a polyatomic ion means that an oxygen atom in the root "ate" ion has been replaced by a sulfur atom. For example, the sulfate ion is SCfi2-, while the thiosulfate ion is S2032-. Notice that the valence does not change. 

Step 3 Balance any polyatomic ions, such as sulfate, SCU2-, that occur on both sides of the chemical equation as an ion unit. That is, do not split a sulfate ion into 1 sulfur atom and 4 oxygen atoms. Balance this ion as one unit. 

Solution The first two ions are single atom anions and are called sulfide and nitride. The next two are binary ionic compounds, calcium fluoride and potassium sulfide. The polyatomic ions hydroxide and sulfate are present in sodium hydroxide and sodium sulfate. Finally, the last two compounds are covalently bonded and are called sulfur trioxide and carbon tetrachloride. 

You already know how to name monatomic ions. How do you name polyatomic ions Most polyatomic ions are oxyanions. An oxyanlon is a polyatomic ion composed of an element, usually a nonmetal, bonded to one or more oxygen atoms. Many oxyanions contain the same nonmetal and have the same charges but differ in the number of oxygen atoms. More than one oxyanion exists for some nonmetals, such as nitrogen and sulfur. These ions are easily named using the following conventions. 

Sulfite ion, 803, is an example of a polyatomic ion of the AB3U type. It is a trigonal pyramidal ion with an unshared pair on the sulfur atom. 

The Group VIA elements below oxygen form some covalent compounds of the ABg type by sharing their six valence electrons with six other atoms. Sulfur hexafluoride, SFg (mp — 51 °C), an unreactive gas, is an example. Sulfur hexafluoride molecules are nonpolar octahedral molecules. The hexafluorophosphate ion, PFg, is an example of a polyatomic ion of the type AB. ... 

We can now consider the effect of the size and shape of the anion on the symmetry and dimensions of the unit cell. For minerals, the anion can vary widely. So far, we have talked only about monatomic (single atom) anions, but many minerals contains polyatomic anions such as carbonate, sulfate, phosphate, vanadate, and, of course, silicates. These are all oxy anions that is, they contain some central atom surrounded by oxygens. It is important to understand that in these anions the oxygens are attached to the central atom by covalent bonds (the bonds may, of course, contain some ionic character). The sulfate, phosphate, vanadate, and nesosilicate ions are tetrahedral in shape. For example, the snlfate ion contains a sulfur at the center of a tetrahedron, as shown below (remember the entire species has a charge of 2-, which is not shown in this structural representation) ... 

Figure 2-1 shows the nuclear notation (a way of writing elements that gives information about the nucleus of element) for the 82 polyatomic ion with 16 neutrons on each sulfur atom, or nuclide. 

Nuclear notation forSr polyatomic ion with 16 neutrons on each sulfur atom. 

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