Nitrides sulfur

Sulfur-nitrogen compounds are currently the subject of intense research. Structurally, these compounds call to mind the allotropes of sulfur discussed in the last section, but their preparations and properties are not easily rationalized. 

Deuterosulfuric acid prepared in this way melts at about 11°. It can be purified if necessary by fractional freezing to maximum melting point (14.10° after 5 cycles). 

The physical properties of anhydrous sulfuric and deuterosulfuric acids are compared in the following table.1,2 

Checked by William L. Jolly, Ulrich de la Camp, James D. Macom-BER,f and H. Fritz Woeller  

The following procedures give the synthesis of tetrasulfur tetranitride, disulfur dinitride, polymeric sulfur nitride, and tetrasulfur dinitride. 

For the preparation of this compound the reaction between ammonia and disulfur dichloride, S2CI2, is employed. Besides tetrasulfur tetranitride, sulfimide, S7NH, some sulfur, and ammonium chloride also are formed. 

The chloride anion produced then carries out a nucleophilic displacement on one of the silyl groups, producing trimethylsilyl chloride in the process  

An intramolecular nucleophilic displacement, followed by chloride-mediated desilylation, leads to the formation of a bis(trimethylsilyl)-S2N2 ring  

The nitrogens in these rings are nucleophilic, and further N-on-S attacks leads to the creation of a tetrakis(trimethylsilyl)-S4N4 ring, whieh seems clearly indicated as a precursor of the final product, S4N4  

The silylated S4N4 ring now needs to be oxidized (the trimethylsilyl group may be viewed as a hydrogen surrogate) and that is accomplished with SO2CI2, as follows  

The cationic nitrogen intermediate thus produced is expected to be stabilized by the adjacent sulfiirs. The departing chloride anion now attacks another silyl group, followed by 

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In 1975, University of Pennsylvania scientists reported synthesis of polymeric sulfur nitride. 

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

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. 

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. 

M. M. Labes, P. Love and L. F. Nichols, Poly(sulfur nitride) A Metallic, Superconducting Polymer, Chem. Rev., 79, 1 (1979). 

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. 

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 ... 

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. ... 

Nitrogen Sulfide. (Sulfur Nitride, Nitrogen Tetrasuifide). See under List of Nitride Compounds in this Vol... 

See Lithium nitride Transition metal halides Sulfur nitrides... 

See Trimethylsilyl azide Selenium halides See also Poly (sulfur nitride) See other nitrides See related N-S COMPOUNDS... 

The endothermic nitride is susceptible to explosive decomposition on friction, shock or heating above 100°C [1], Explosion is violent if initiated by a detonator [2], Sensitivity toward heat and shock increases with purity. Preparative precautions have been detailed [3], and further improvements in safety procedures and handling described [4], An improved plasma pyrolysis procedure to produce poly (sulfur nitride) films has been described [5], Light crushing of a small sample of impure material (m.p. below 160°C, supposedly of relatively low sensitivity) prior to purification by sublimation led to a violent explosion [6] and a restatement of the need [4] for adequate precautions. Explosive sensitivity tests have shown it to be more sensitive to impact and friction than is lead azide, used in detonators. Spark-sensitivity is, however, relatively low [7],... 

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