The salt [F
5SN(H)
Xe][AsF
6] has been synthesized by the reaction of [F
5SNH
3][AsF
6] with XeF
2 in anhydrous HF (aHF) and BrF
5 solvents and by solvolysis of [F
3S
![](http://pubs.acs.org/images/entities/tbd1.gif)
NXeF][AsF
6] in aHF. Both F
5SN(H)Xe
+ and F
5SNH
3+ have been characterized by
129Xe,
19F, and
1H NMR spectroscopy in aHF (−20 °C) and BrF
5 (supercooled to −70 °C). The yellow [F
5SN(H)Xe][AsF
6] salt was crystallized from aHF at −20 °C and characterized by Raman spectroscopy at −45 °C and by single-crystal X-ray diffraction at −173 °C. The Xe−N bond length (2.069(4) Å) of the F
5SN(H)Xe
+ cation is among the shortest Xe−N bonds presently known. The cation interacts with the AsF
6− anion by means of a Xe---F−As bridge in which the Xe---F distance (2.634(3) Å) is significantly less than the sum of the Xe and F van der Waals radii (3.63 Å) and the AsF
6− anion is significantly distorted from
Oh symmetry. The
19F and
129Xe NMR spectra established that the [F
5SN(H)Xe][AsF
6] ion pair is dissociated in aHF and BrF
5 solvents. The F
5SN(H)Xe
+ cation decomposes by HF solvolysis to F
5SNH
3+ and XeF
2, followed by solvolysis of F
5SNH
3+ to SF
6 and NH
4+. A minor decomposition channel leads to small quantities of F
5SNF
2. The colorless salt, [F
5SNH
3][AsF
6], was synthesized by the HF solvolysis of F
3S
![](http://pubs.acs.org/images/entities/tbd1.gif)
NAsF
5 and was crystallized from aHF at −35 °C. The salt was characterized by Raman spectroscopy at −160 °C, and its unit cell parameters were determined by low-temperature X-ray diffraction. Electronic structure calculations using MP2 and DFT methods were used to calculate the gas-phase geometries, charges, bond orders, and valencies as well as the vibrational frequencies of F
5SNH
3+ and F
5SN(H)Xe
+ and to aid in the assignment of their experimental vibrational frequencies. In addition to F
5TeN(H)Xe
+, the F
5SN(H)Xe
+ cation provides the only other example of
xenon bonded to an sp
3-hybridized nitrogen center that has been synthesized and structurally characterized. These cations represent the strongest Xe−N bonds that are presently known.