The Sulfur Nitrides

The sulfur nitrides have been the subject of several reviews (206—208). Although no commercial appHcations have as yet been developed for these compounds, some interest was stimulated by the discovery that polythiazyl, a polymeric sulfur nitride, (SN), with metallic luster, is electroconductive (see Inorganic highpolymers) (208,209). Other sulfur nitrides are unstable. Tetrasulfur nitride is explosive and shock-sensitive. 

The sulfur nitrides S15N2 and S sN2 are (formally) derived from cyclo-Sg (or S7NH) and can be prepared by reacting S7NH with SCI2 and S2CI2 respectively ... 

Acetone-Pis an unstable, white powder or crystalline mass with a melting point of 90 to 93 Celsius. The solid is insoluble in water, but soluble in ether and tetrahydrofuran. It is quite unstable and is rarely used in military or commercial explosives. However it can be utilized as a primary explosive in blasting caps or detonators when desensitized with appropriate materials. To do so, it should be mixed with gum Arabic, carbon black, tri sodium phosphate, chalk, or silicon dioxide powder, and then mixed with a small amount of paraffin s or saturated oils prior to use. Acetone-P can also be slurried with 10% water and 5% hexane for use in blasting caps or detonators. Pure acetone-P should not be used by itself, as it will decay over time potentially leading to explosions. Acetone-P is rather volatile, and a small sample left out in the open will completely evaporate after several days—partly due to decomposition. Acetone-P can also be used in initiating compositions when mixed with sulfur nitride or other primary explosives, and then added to a small amount of a saturated oil. The sulfur nitride and other primary explosives can be replaced by bari urn chromate, copper perchlorate, or lead chromate. Even when acetone-P has been successfully desensitized, it should be used withi n 2 weeks of preparation. ... 

This synthesis can be extended to the preparation of the sulfur nitride complexes of other transition and post-transition metals. Furthermore, Ni(S2N2H)2 can serve as a starting material for the synthesis of many derivatives of this compound by replacement of the acidic N—H proton. Such compounds include substituents on one or two of the nitrogen atoms, as well as groups that bridge the cis-nitrogen atoms. 

The conducting polymer poly(sulfur nitride) is unusual in that it is crystalline, consisting of chains of sulfur and nitrogen packed in parallel. 

Polymer and chain formation is another property of chalcogen-nitrogen compounds that distinguishes them from their oxygen analogues. In addition to the unique, superconducting poly(sulfur nitride) (SN) (1.24) (Section 14.2), a variety of poly(thiazyl) chains such as RS5N4R (1.25) (Section 14.3) have been characterized. Interest in these chains stems from their possible use as models for the behaviour of (SN) and as components in molecular materials, e.g., as molecular wires. 

A. J. Banister and I. B. Gorrell, Poly(sulfur nitride) The Fkst Polymeric Metal, Adv. Mater., 10, 1415 (1998). 

Unlike nitric oxide, NO, the monomeric radical sulfur nitride, NS, is only known as a short-lived intermediate in the gas phase. Nevertheless the properties of this important diatomic molecule have been thoroughly investigated by a variety of spectroscopic and other physical techniques (Section 5.2.1). The NS molecule is stabilized by coordination to a transition metal and a large number of complexes, primarily with metals from Groups 6, 7, 8 and 9, are known. Several detailed reviews of the topic have been published. ... 

Another possible modification of poly(sulfur nitride) that is expected to produce conducting polymers is the replacement of alternating sulfur in the thiazyl chain by an RC unit, i.e., [(R)CNSN]x. This type of polymer would have five r-electrons per four atoms in the repeating unit and, consequently, would have a partially occupied conducting band. The prospect of tuning the electronic properties of this polymer by... 

It will be convenient to describe first the binary. sulfur nitrides SjN,. and then the related cationic and anionic species, S,Nv. The sulfur imides and other cyclic S-N compounds will then be discus.sed and this will be followed by sections on S-N-halogen and S-N-O compounds. Several compounds which feature i.solated S<—N, S-N, S = N and S=N bonds have already been mentioned in the. section on SF4 e.g. F4S NC,H, F5S-NF2. F2S = NCF3, and FiS=N (p. 687). Flowever. many SN compounds do not lend themselves to simple bond diagrams, - and formal oxidation states are often unhelpful or even misleading. 

Sulfur reacts with nitrogen to form polymeric sulfur nitrides (SNx) or polythiazyls. These polymers were found to have the optical and electrical properties of metals. ... 

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