Molecular Geometry & Lewis Structures
Electron-domain analysis, geometry, bond angle and step-by-step construction for SF6 (CAS 2551-62-4) — with the practical supply context B2B and laboratory buyers need.
SF6 has a Octahedral molecular geometry (AX6, octahedral) with a bond angle of 90° between every adjacent pair, 180° between opposite pairs. The central sulfur carries 6 bonding domain(s) and 0 lone pair(s) — 6 electron domains in total. Six equivalent domains define the octahedron; the symmetric fluorine shell explains the chemical inertness.
Hybridisation is conventionally described as sp3d2 (hypervalent description). Polarity: Nonpolar (perfect symmetry).
| Parameter | Sulfur Hexafluoride (SF6) |
|---|---|
| CAS Registry Number | 2551-62-4 |
| Molecular formula | SF6 |
| Molar mass | 146.06 g/mol |
| Total valence electrons | 48 |
| Central atom | Sulfur |
| Bonding domains (σ) | 6 |
| Lone pairs on central atom | 0 |
| Electron domains (steric number) | 6 |
| Electron-pair geometry | Octahedral |
| Molecular geometry (shape) | Octahedral |
| VSEPR notation | AX6 |
| Bond angle | 90° between every adjacent pair, 180° between opposite pairs |
| Hybridisation (conventional) | sp3d2 (hypervalent description) |
| Polarity | Nonpolar (perfect symmetry). |
| Lewis structure guide | SF6 Lewis structure |
Molar mass is the average value rounded for procurement use. Hybridisation labels are the conventional VSEPR-level description; orbital treatment becomes more nuanced at higher levels of theory.
A worked diagram of this molecule is kept in the companion guide: SF6 Lewis structure.
VSEPR theory counts electron domains — every σ bond counts once regardless of bond order, and every lone pair counts once. SF6 has 6 such domains around the sulfur: 6 bonding and 0 lone. 6 domains correspond to a octahedral electron-domain arrangement; with no lone pair to hide the observed molecular shape is octahedral (AX6).
Bond angle: 90° between every adjacent pair, 180° between opposite pairs because six equivalent domains define the octahedron; the symmetric fluorine shell explains the chemical inertness.
Polarity: Nonpolar (perfect symmetry).
Geometry shortcut for recall
Steric number 6 → parent arrangement octahedral; subtract 0 lone positions and the visible shape is octahedral. Same electron count, different lone-pair bookkeeping, different geometry — always count the domains before naming the shape.
Predicting a flat hexagon — six equivalent domains only form a three-dimensional octahedron.
Sulfur exceeds the octet — the classic period-3 expansion.
Dielectric medium in high-voltage switchgear; leak-rate management and reclamation clauses are environmental requirements (GWP ≈ 23,500), not optional extras.
Structure-level identity is exactly what a purchase order has to fix: the same molecular formula can hide isomers, hydrates or salt forms with different handling profiles. Before ordering, match CAS (2551-62-4), assay, water content and container rating against the datasheet, and request the COA batch that will ship.
Octahedral. The 6 electron domains around the central sulfur adopt a octahedral arrangement, and with no lone pairs on the central atom the visible shape is octahedral.
90° between every adjacent pair, 180° between opposite pairs, because six equivalent domains define the octahedron; the symmetric fluorine shell explains the chemical inertness.
Nonpolar (perfect symmetry).
SF6 has no lone pair on the central atom — every domain is a bond.
Editorial note
This page explains molecular geometry and Lewis-structure construction for education and procurement due-diligence. It is not a safety datasheet; for handling, exposure and transport limits consult the current SDS and local regulations.