**Hexachlorocyclotriphosphazene** (chemical formula: **(NPCl?)?**) is an important organophosphorus compound. Below are its key details:  

### **Chemical Properties**  

- **Structure**: Cyclic phosphazene structure, consisting of alternating three phosphorus atoms and three nitrogen atoms, with each phosphorus atom bonded to two chlorine atoms.  

- **Appearance**: Typically a white crystalline solid.  

- **Molecular Weight**: 347.66 g/mol.  

### **Main Applications**  

1. **Polymer Synthesis**: Used as a precursor for polyphosphazenes, which are applied in high-performance elastomers, flame-retardant materials, etc.  

2. **Flame Retardant**: Utilized in the synthesis of efficient flame retardants for plastics, rubber, and textiles.  

3. **Chemical Intermediate**: Employed in the synthesis of pharmaceuticals, agrochemicals, and other specialty chemicals.  

### **Safety Information**  

- **Hazards**: Irritating to skin, eyes, and respiratory tract. Should be handled in a well-ventilated environment.  

- **Storage Conditions**: Store in a sealed container, avoiding moisture and high temperatures.  

### **Additional Information**  

- **CAS Number**: 940-71-6  

- **EINECS Number**: 233-782-3  

If you need more detailed technical data or application examples, please refer to chemical databases or related literature.