EPA Extremely Hazardous Substances List. Reported in EPA TSCA Inventory.

OSHA PEL: TWA 0.02 ppm (Te)
ACGIH TLV: TWA 0.02 ppm (Te)
DOT Classification:  2.3; Label: Poison Gas

The Tellurium hexafluoride, with the CAS registry number 7783-80-4 and EINECS registry number 232-027-0, has the systematic name of hexafluoro-λ⁶-tellane. And the molecular formula of this chemical is TeF₆. It is a colorless, highly toxic gas with an extremely unpleasant smell. And it is often used as chemical medicine.

The physical properties of Tellurium hexafluoride are as following: (1)ACD/LogP: -1.94; (2)# of Rule of 5 Violations: 1; (3)ACD/LogD (pH 5.5): -1.94; (4)ACD/LogD (pH 7.4): -1.94; (5)ACD/BCF (pH 5.5): 1; (6)ACD/BCF (pH 7.4): 1; (7)ACD/KOC (pH 5.5): 2.1; (8)ACD/KOC (pH 7.4): 2.1; (9)#H bond acceptors: 9; (10)#H bond donors: 5; (11)#Freely Rotating Bonds: 12; (12)Polar Surface Area: 83.07 Å²; (13)Index of Refraction: 1.622; (14)Molar Refractivity: 92.74 cm3; (15)Molar Volume: 263 cm³; (16)Polarizability: 36.76×10^-24cm³; (17)Surface Tension: 59.4 dyne/cm; (18)Density: 1.415 g/cm³; (19)Flash Point: 342.4 °C; (20)Enthalpy of Vaporization: 99.67 kJ/mol; (21)Boiling Point: 642.6 °C at 760 mmHg; (22)Vapour Pressure: 2.17E-17 mmHg at 25°C.

Properties of Tellurium hexafluoride: It is a highly symmetric octahedral molecule, and its physical properties resemble the sulfur and selenium analogs. Due to the increase in molecular weight, it is less volatile. At temperatures below -38 °C, this chemical condenses to a volatile white solid.

Preparation of Tellurium hexafluoride: It can be prepared by passing fluorine gas over tellurium metal at 150 °C. It can also be prepared by passing fluorine gas over TeO₃ or indirectly by reacting TeO₂ with SeF₄ to produce TeF₄ and then heating TeF4 in excess of 200 °C to make TeF₆ and Te.

You should be cautious while dealing with this chemical. It is harmful by inhalation, and it may also cause burns. Besides, if contact with acids, it will liberate toxic gas. Therefore, you had better take the following instructions: Keep container tightly closed in a cool place; Keep container in a well-ventilated place; Wear suitable protective clothing, gloves and eye/face protection; In case of accident or if you feel unwell, seek medical advice immediately (show label where possible).

You can still convert the following datas into molecular structure:
(1)SMILES: F[Te](F)(F)(F)(F)F
(2)InChI: InChI=1/F6Te/c1-7(2,3,4,5)6
(3)InChIKey: NNCGPRGCYAWTAF-UHFFFAOYAP

The toxicity data is as follows: