Tetrasulfur tetranitride

Tetrasulfur tetranitride
Tetrasulfur tetranitride
CAS number 28950-34-7
PubChem 141455
ChemSpider 124788 YesY
Jmol-3D images Image 1
Image 2
Molecular formula N4S4
Molar mass 184.287 g mol-1
Appearance Vivid, orange, opaque crystals
Melting point

187 °C, 460 K, 369 °F

 YesY tetranitride (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Tetrasulfur tetranitride is an inorganic compound with the formula S4N4. This gold-poppy coloured solid is the most important binary sulfur nitride, which are compounds that contain only the elements sulfur and nitrogen. It is a precursor to many S-N compounds and has attracted wide interest for its unusual structure and bonding.[1][2]

Nitrogen and sulfur have similar electronegativities. When atoms are so evenly matched, they often form extensive families of covalently bonded structures. Indeed, a large number of S-N and S-NH compounds are known with S4N4 as their parent.



S4N4 adopts an unusual “extreme cradle” structure, with D2d point group symmetry. It can be viewed as a derivative of a hypothetical eight-membered ring of alternating sulfur and nitrogen atoms. The pairs of sulfur atoms across the ring are separated by 2.586 Å, resulting in a cage-like structure as determined by single crystal X-Ray diffraction.[3] The nature of the "transannular" S–S interactions remains a matter of investigation because it is significantly shorter than the sum of the van der Waal's distances[4] but has been explained in the context of molecular orbital theory.[1] The bonding in S4N4 is considered to be delocalized, which is indicated by the fact that the bond distances between neighboring sulfur and nitrogen atoms are almost the same.


S4N4 is stable to air. It is, however, unstable in the thermodynamic sense with a positive enthalpy of formation of +460 kJ mol−1. This endothermic enthalpy of formation anticipates its inherent instability, and originates in the difference in energy of S4N4 compared to its highly stable decomposition products:

2 S4N4 → 4 N2 + S8

Although many complex molecules are unstable in a thermodynamic sense yet stable kinetically, this is uncommon for very simple compositions, such as sulfur nitride.

Because one of its decomposition products is a gas, S4N4 is an explosive.[1] Purer samples tend to be more explosive. Small samples can be detonated by striking with a hammer.

S4N4 is thermochromic, changing from pale yellow below −30 °C to orange at room temperature to deep red above 100 °C.[1]


S4N4 was first prepared in 1835 by W. Gregory, by the reaction of sulfur monochloride with ammonia.[5]

Until recently, S4N4 was prepared by the reaction of ammonia with SCl2 in carbon tetrachloride followed by extraction into dioxane, producing sulfur and ammonium chloride as side-products:[6]

24 SCl2 + 64 NH3 → 4 S4N4 + S8 + 48 NH4Cl

A related synthesis employs sulfur monochloride and NH4Cl instead:[1]

4 NH4Cl + 6 S2Cl2 → S4N4 + 16 HCl + S8

A more recent synthesis entails the use of [(Me3Si)2N]2S as a precursor with pre-formed S–N bonds. [(Me3Si)2N]2S is prepared by the reaction of lithium bis(trimethylsilyl)amide and SCl2.

2 [(CH3)3Si]2NLi + SCl2 → [((CH3)3Si)2N]2S + 2 LiCl

The [((CH3)3Si)2N]2S reacts with the combination of SCl2 and SO2Cl2 to form S4N4, trimethylsilyl chloride, and sulfur dioxide:[7]

[((CH3)3Si)2N]2S + SCl2 + SO2Cl2 → S4N4 + 4 (CH3)3SiCl + SO2

Acid-base reactions


S4N4 serves as a Lewis base by binding through nitrogen to strongly Lewis acidic compounds such as SbCl5 and SO3. The cage is distorted in these adducts, thus delocalization of electrons may be disrupted.[1]

S4N4 + SbCl5 → S4N4·SbCl5
S4N4 + SO3 → S4N4·SO3

The reaction of [Pt2Cl4(PMe2Ph)2] with S4N4 is reported to form a complex where a sulfur forms a dative bond to the metal. This compound upon standing is isomerised to a complex in which a nitrogen atom forms the additional bond to the metal centre.

It is protonated by HBF4 to form a tetrafluoroborate salt:

S4N4 + HBF4 → [S4N4H+][BF

The soft Lewis acid CuCl forms a polymer containing intact S4N4 rings as the bridging ligands:[1]

n S4N4 + n CuCl → (S4N4)n-μ-(-Cu-Cl-)n

S4N4 is sensitive to hydrolysis in the presence of base. Dilute NaOH hydrolyzes S4N4 as follows, yielding thiosulfate and trithionate:[1]

2 S4N4 + 6 OH + 9 H2O → S2O2−
+ 2 S3O2−
+ 8 NH3

More concentrated base yields sulfite:

S4N4 + 6 OH + 3 H2O → S2O2−
+ 2 SO2−
+ 4 NH3

Reactions with metal complexes

This area has been reviewed.[2][8]

Reactions of S4N4 where the ring remains intact

S4N4 reacts with Vaska's complex ([Ir(Cl)(CO)(PPh3)2] in an oxidative addition reaction to form a six coordinate iridium complex where the S4N4 binds through two sulfur atoms and one nitrogen atom. This compound arises by the formal breaking of one S-N bond in the oxidative addition, followed by the coordination of the lone pair on another sulfur atom to form a dative bond. A related Pt(IV) compound arises from Zeise's salt.

Reactions of S4N4 where the ring does not remain intact

The reaction of S4N4 with the [Pd2Cl6]2− anion forms a series of three palladium complexes in which the S4N4 ring has been fragmented.

S4N4 as a precursor to other S-N compounds

Many important S-N compounds are prepared from S4N4.[9] Reaction with piperidine generates [S4N5]:

3 S4N4 + 4 C5H10NH → (C5H10NH2)+[S4N5] + (C5H10N)2S + ⅜ S8 + N2

It is indicative of the richness of this area that a related cation is also known, i.e. [S4N5]+.

Treatment with tetramethylammonium azide produces the heterocycle [S3N3]:

S4N4 + NMe4N3 → NMe4[S3N3] + ⅛ S8 + 2 N2

In the language of electron counting, [S3N3] has 10 pi-electrons: 2e/S plus 1e/N plus 1e for the negative charge.

In an apparently related reaction, the use of PPN+N3 gives a salt containing the blue [NS4] anion:[10]

2 S4N4 + PPN(N3) → PPN[NS4] + ½ S8 + 5 N2

The anion NS4 has a chain structure described using the resonance [S=S=N-S-S] ↔ [S–S–N=S=S].

Reaction with acetylenes

S4N4 reacts with electron poor acetylenes.[11]


Passing gaseous S4N4 over silver metal yields the low temperature superconductor polythiazyl or polysulfurnitride (transition temperature (0.26±0.03) K[12]), often simply called "(SN)x". In the conversion, the silver first becomes sulfided, and the resulting Ag2S catalyzes the conversion of the S4N4 into the four-membered ring S2N2, which readily polymerizes.[1]

S4N4 + 8 Ag → 4 Ag2S + 2 N2
S4N4 → (SN)x

Miscellaneous facts

S4N4 has been shown to co-crystallize with benzene and the C60 molecule.[13]


The selenium compound Se4N4 is known and has been the subject of some research.[14][15] In addition, adducts of aluminium chloride with Se2N2 have been isolated, this is formed from Se4N4.[16]


S4N4 is shock-sensitive, thus grinding solid samples should be avoided. Purer samples are reportedly more sensitive than those contaminated with elemental sulfur.


  1. ^ a b c d e f g h i Greenwood, N. N.; Earnshaw, A. Chemical Elements; 2nd edition; Butterworth-Heinemann: Boston, MA, 1997, pp 721-725.
  2. ^ a b Chivers, T. “A Guide To Chalcogen-Nitrogen Chemistry” World Scientific Publishing Company: Singapore; 2004. ISBN 981-256-095-5
  3. ^ Brahama D. Sharma and Jerry Donohue (1963). "The crystal and molecular structure of sulfur nitride, S4N4". Acta Crystallographica 16 (9): 891–897. doi:10.1107/S0365110X63002401. 
  4. ^ H. S. Rzepa and J. D. Woollins (1990). "A PM3 SCF-MO Study of the Structure and Bonding in the Cage Systems S4N4 and S4N4X (X=N [+], N[-], S, N2S, P[+], C, Si, B[-] and Al[-])". Polyhedron 9 (1): 107. doi:10.1016/S0277-5387(00)84253-9. 
  5. ^ Jolly, W. L.; Steven A. Lipp (January 1971). "Reaction of tetrasulfur tetranitride with sulfuric acid". Inorganic Chemistry 10 (1): 33–38. doi:10.1021/ic50095a008.  edit
  6. ^ Villena-Blanco, M.;Jolly, W.L.; Tyree (1967). "Tetrasulfur Tetranitride, S4N4". Inorg. Synth. 9: 98–102. doi:10.1002/9780470132401.ch26. 
  7. ^ Maaninen, A.; Shvari, J.; Laitinen, R.S.; Chivers, T; (2002). Inorg. Synth. 33: 196–199. doi:10.1002/0471224502.ch4. 
  8. ^ Paul. F. Kelly, Alexandra. M.Z. Slawin, David J. Williams and J. Derek Woollins (1992). "Caged explosives: metal-stabilized chalcogen nitrides". Chemical Society Reviews 21 (4): 245. doi:10.1039/CS9922100245. 
  9. ^ Bojes, J.; Chivers, T; Oakley, R. D. (1989). "Binary Cyclic Nitrogen-Sulfur Anions". Inorg. Synth. 25: 30–40. doi:10.1002/9780470132562.ch7. 
  10. ^ Bojes, J.; Chivers, T; Oakley, R. D. (1989). "Binary Catena-Nitrogen-Sulfur Anions". Inorg. Synth. 25: 35–38. doi:10.1002/9780470132562.ch8. 
  11. ^ P. J. Dunn and H. S. Rzepa (1987). "The Reaction between Tetrasulphur Tetranitride (S4N4) and Electron-deficient Alkynes. A Molecular Orbital Study". Journal of the Chemical Society, Perkin Transactions 2 (11): 1669–1670. doi:10.1039/p29870001669. 
  12. ^ R. L. Greene, G. B. Street and L. J. Suter, Superconductivity in Polysulfur Nitride (SN)x, Phys. Rev. Lett. 34, 577–579 (1975) doi:10.1103/PhysRevLett.34.577
  13. ^ Konarev, D.V. et al. (2000). "Donor-acceptor Complexes of Fullerene C60 with Organic and Organometallic Donors". Journal of Materials Chemistry 10 (4): 803–818. doi:10.1039/a907106g. 
  14. ^ Kelly, P.F. and Woollins, J.D., (1993). "The Reactivity of Se4N4 in Liquid Ammonia". Polyhedron 12 (10): 1129–1133. doi:10.1016/S0277-5387(00)88201-7. 
  15. ^ Kelly, P.F., Slawin, A.M.Z. and Soriano-Rama, A. (1997). "Use of Se4N4 and Se(NSO)2 in the preparation of palladium adducts of diselenium dinitride, Se2N2; crystal structure of [PPh4]2[Pd2Br6(Se2N2)". Dalton Transactions (4): 559–562. doi:10.1039/a606311j. 
  16. ^ Kelly, P.F. and Slawin, A.M.Z. (1996). "Preparation and crystal structure of [(AlBr3)2(Se2N2)], the first example of a main-group element adduct of diselenium dinitride". Dalton Transactions (21): 4029–4030. doi:10.1039/DT9960004029. 

Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • tetrasulfur tetranitride — noun a simple binary compound of sulfur and nitrogen, SN, having a ring structure; it is explosive See Also: sulfur nitride …   Wiktionary

  • tetrasulphur tetranitride — noun alternative spelling of tetrasulfur tetranitride …   Wiktionary

  • nitride — /nuy truyd, trid/, n. Chem. a compound, containing two elements only, of which the more electronegative one is nitrogen. [1840 50; NITR + IDE] * * * ▪ chemical compound Introduction       any of a class of chemical compounds in which nitrogen is… …   Universalium

  • Inorganic chemistry — For the journal, see Inorganic Chemistry (journal). Inorganic compounds show rich variety: A: Diborane features unusual bonding B: Caesium chloride has an archetypal crystal structure C: Fp2 is an organometallic complex D …   Wikipedia

  • Дитиодихлорид — Дитиодихлорид …   Википедия

  • Sulfur — This article is about the chemical element. For other uses, see Sulfur (disambiguation). phosphorus ← sulfur → chlorine …   Wikipedia

  • Nitride — In chemistry, a nitride is a compound of nitrogen where nitrogen has a formal oxidation state of −3. Nitrides are a large class of compounds with a wide range of properties and applications.[1] The nitride ion, N3–, is never encountered in… …   Wikipedia

  • List of inorganic compounds — Tentative listing related to this page, inorganic compounds by element (presently under construction), as well as . This list is not necessarily complete or up to date ndash; if you see an article that should be here but isn t (or one that… …   Wikipedia

  • Contact explosive — generally refers to any substance that will explode when relatively small quantities of energy are applied to the substance, whether that be heat, light, sound, or physical pressure and even Alpha radiation. Examples include: Compound Sensitivity …   Wikipedia

  • Sulfur nitride — can refer to a number of sulfur nitrogen compounds: tetrasulfur tetranitride, S4N4 disulfur dinitride, S2N2 polythiazyl, (SN)x Additionally, some unstable species are known: mononitrogen monosulfide, SN, analogous to nitrogen monoxide, NO SN2,… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”