Niobium diselenide is a binary inorganic compound of niobium and selenium with the formula NbSe 2 , dark gray crystals.
| Niobium diselenide | |
|---|---|
| Are common | |
| Systematic name | Niobium diselenide |
| Traditional names | Seleny Niobium |
| Chem. formula | NbSe 2 |
| Physical properties | |
| condition | dark gray crystals |
| Molar mass | 250.83 g / mol |
| Density | 6.3 g / cm³ |
| Thermal properties | |
| T. melt. | > 1300 ° C |
| Classification | |
| Reg. CAS number | 12034-77-4, 845890-99-5 |
| Pubchem | |
| Reg. EINECS number | 234-811-8 |
| SMILES | |
| Inchi | |
| Chemspider | |
Content
Getting
- Fusion of stoichiometric amounts of pure substances:
- {\ displaystyle {\ mathsf {Nb + 2Se \ {\ xrightarrow {500 ^ {o} C}} \ NbSe_ {2}}}}
Physical Properties
Niobium diselenide forms dark gray crystals of several modifications [1] :
- 1T-NbSe 2 , high-temperature modification (T> 910 ° C);
- 2H-NbSe 2 , hexagonal system , space group P 3m1 or P 6 3 / mmc [2] , cell parameters a = 0.3447 nm, c = 1.2561 nm, Z = 2;
- 3R-NbSe 2 , trigonal system , space group R 3m ;
- 4H (a) -NbSe 2 , hexagonal syngony;
- 4H (d) -NbSe 2 , hexagonal syngony, high-temperature modification (T> 910 ° C).
At a temperature of 8.6 K, it transforms into a superconducting state.
Notes
- ↑ О.К. Sinelnichenko, J. I. Tishkovets, M.V. Karpets, O. Yu. Hijun Electronic structure of 3R-polytypes with dis- elenes in a new type of molibden / / Add. NAS of Ukraine. - 2008. - T. 7 . - p . 86-93 .
- ↑ EA Antonova, KV Kiseleva, SA Medvedev. Superconductivity of layered structures. investigation of the solutions in the NbSe 2 -NbTe 2 system // Soviet Physics JETP. - 1971. - V. 32 , № 1 . - pp . 31-33 .
Literature
- State diagrams of double metal systems / Ed. N. P. Lyakishev. - M .: Mashinostroenie, 2001. - T. 3 Book 1. - 972 p. - ISBN 5-217-02843-2 .