Hexachlorophosphazene
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| Hexachlorophosphazene | |
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| General | |
| Systematic name | Hexachlorotriphosphazene |
| Other names | Phosphonitrilic chloride 1,3,5,2,4,6-Triazatriphos- phorine-2,2,4,4,6,6-hexachloride 1,3,5-Triaza-2,4,6-triphos- phorin-2,2,4,4,6,6-hexachloride Hexachlorocyclotriphosphazene |
| Molecular formula | N3Cl6P3 |
| SMILES | ? |
| Molar mass | 347.66 g/mol |
| Appearance | colorless crystals |
| CAS number | [940-71-6] |
| Properties | |
| Density and phase | 1.98 g/mL at 25 °C |
| Solubility in water | dec. |
| Other solvents | soluble in chlorocarbons |
| Melting point | 112-115 °C |
| Boiling point | decomp. |
| Crystal structure | ? |
| Dipole moment | 0 D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | mild irritant |
| NFPA 704 | |
| Flash point | n.a. |
| R/S statement | R: 14-34 S: 26-36/37/39-45 |
| RTECS number | ? |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Related compounds | PCl5 POCl3 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Hexachlorophosphazene is the chemical compound with the formula N3Cl6P3. It is a cyclic compound, whose chemical formula is more descriptively written as (PNCl2)3. It is a trimer of the hypothetical compound N≡PCl2.
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[edit] Synthesis
The reaction of PCl5 and NH4Cl affords substances with the empirical formula PNCl2:[1] Purification by sublimation gives mainly the trimer (PNCl2)3 and tetramer (PNCl2)4. These rings were characterized by Liebig in his study of the reaction of PCl5 and NH3:
- PCl5 + NH4Cl → 1/n(NPCl2)n + 4 HCl
Typical solvents are chlorobenzene.
[edit] Inorganic rings
Chemists have long known of rings containing carbon, e.g. benzene, pyridine, and cyclohexane. Related cyclic compounds lacking in carbon have been the subject of focused study. Hexachlorophosphazene is an archetype of this class of inorganic rings. Others include borazine, S4N4, and cyclic siloxanes.
[edit] "Inorganic rubber"
Hexachlorophosphazene has attracted considerable interest as a precursor to "inorganic rubber".[2] Upon heating to ca. 250 °C, the trimer polymerizes to give the linear polymer (PNCl2)n via a ring-opening polymerization process. This polymer is soluble in organic solvents such as THF and benzene, wherein it can be derivatized by replacement of the P-Cl bonds with P-OR or P-NR2 bonds (R = alkyl, aryl). The organically modified polymer is hydrolytically stable and exhibits some attractive properties such as low glass transition temperatures.
[edit] References
- ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- ^ Mark, J. E.; Allcock, H. R.; West, R. “Inorganic Polymers” Prentice Hall, Englewood, NJ: 1992. ISBN 0-13-465881-7.
