Teflic acid

Names
IUPAC name Pentafluoroorthotelluric acid
Other names Teflic acid
Identifiers
CAS Number	57458-27-2 Y
3D model (JSmol)	Interactive image
ChemSpider	10331773 Y
ECHA InfoCard	100.161.534
PubChem CID	15243876
CompTox Dashboard (EPA)	DTXSID60570416
InChI InChI=1S/F5HOTe/c1-7(2,3,4,5)6/h6H Y Key: OAOSLENTGBMCNC-UHFFFAOYSA-N Y InChI=1/F5HOTe/c1-7(2,3,4,5)6/h6H Key: OAOSLENTGBMCNC-UHFFFAOYAO
SMILES F[Te](F)(F)(F)(F)O
Properties
Chemical formula	HOTeF5
Molar mass	239.60 g·mol−1
Appearance	colorless solid
Melting point	39.1 °C (102.4 °F; 312.2 K)
Boiling point	59.7 °C (139.5 °F; 332.8 K)
Acidity (pKa)	8.8 (in Ac2O)[1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	corrosive, toxic
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314
Precautionary statements	P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Teflic acid is a chemical compound with the formula HOTeF₅. This strong acid is related to orthotelluric acid, Te(OH)₆. Teflic acid has a slightly distorted octahedral molecular geometry.

Preparation

Teflic acid was accidentally discovered by Engelbrecht and Sladky. Their synthesis did not yield the anticipated telluryl fluoride TeO₂F₂, but a mixture of volatile telluric compounds, containing HOTeF₅:^[2]

BaTeO₄ + 10 FSO₂OH → HOTeF₅ (25%)

Teflic acid can also be prepared from fluorosulfonic acid and barium tellurate:^[3]

5 FSO₂OH + Ba²⁺[TeO₂(OH)₄]²⁻ → HOTeF₅ + 4 H₂SO₄ + BaSO₄

It is also the first hydrolysis product of tellurium hexafluoride:

TeF₆ + H₂O → HOTeF₅ + HF

Teflates

The conjugate base of teflic acid is called the teflate anion, F₅TeO⁻ (not to be confused with triflate). Many teflates are known, one example being B(OTeF₅)₃, that can be pyrolysed to give acid anhydride O(TeF₅)₂.^[3]

2 B(OTeF₅)₃ → 2 B(OTeF₅)₂F + O(TeF₅)₂

The teflate anion is known to resist oxidation. This property has allowed the preparation several highly unusual species such as the hexateflates M(OTeF₅)−6 (in which M = As, Sb, Bi). Xenon forms the cation Xe(OTeF₅)⁺.^[4]