What Shape Does PCl3 Have?

PCl3 has a Trigonal pyramidal molecular geometry (AX3E, tetrahedral) with a bond angle of ≈100° (Cl–P–Cl 100.3°). The central phosphorus carries 3 bonding domain(s) and 1 lone pair(s) — 4 electron domains in total. The bonding pairs sit farther from the larger phosphorus nucleus while the lone pair stays close, so the lone pair squeezes the pyramidal angle below ammonia's 107.8°.

Hybridisation is conventionally described as sp3. Polarity: Polar.

1. Molecular Identity and Key Parameters

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.

2. Drawing the Lewis Structure of PCl3, Step by Step

1. Count valence electrons: 5 (P) + 3×7 (Cl) = 26 — a total of 26 electrons (13 pairs) must be placed.
2. Build the skeleton: place the phosphorus at the centre and attach the terminal atoms with single bonds; hydrogen is never a central atom. Each single bond consumes 2 electrons.
3. Complete terminal octets: distribute the remaining electrons as lone pairs on the terminal atoms first (hydrogens already carry their duet from the single bond).
4. Satisfy the central atom: Three P–Cl single bonds plus one lone pair on phosphorus.
5. Verify: Octet on all atoms. Apply the standard formal-charge check (valence − nonbonding − half of bonding electrons) to confirm the drawn form.

A worked diagram of this molecule is kept in the companion guide: PCl3 Lewis structure.

3. VSEPR Analysis: Why PCl3 Is trigonal pyramidal

VSEPR theory counts electron domains — every σ bond counts once regardless of bond order, and every lone pair counts once. PCl3 has 4 such domains around the phosphorus: 3 bonding and 1 lone. 4 domains correspond to a tetrahedral electron-domain arrangement; with 1 lone pair excluded from the shape the observed molecular shape is trigonal pyramidal (AX3E).

Bond angle: ≈100° (Cl–P–Cl 100.3°) because the bonding pairs sit farther from the larger phosphorus nucleus while the lone pair stays close, so the lone pair squeezes the pyramidal angle below ammonia's 107.8°.

Polarity: Polar.

4. The Most Common Mistake When Drawing PCl3

5. Why the Geometry Matters in Practice

Central phosphorus intermediate to phosphites, flame-retardant plasticisers (TCPP) and agrochemical actives; iron and acidity limits dominate the COA.

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 (7719-12-2), assay, water content and container rating against the datasheet, and request the COA batch that will ship.

Compare Phosphorus Trichloride (PCl3) supply offers →

6. Quick FAQs on PCl3

7. References

1. IUPAC / Gillespie, Assessment of the VSEPR model. Basis of AXE notation and lone-pair ordering. VSEPR entry
2. PubChem compound record for Phosphorus Trichloride (PCl3). Registry number, formula and computed descriptors. PubChem 7719-12-2
3. Companion Lewis-structure guide on this site. Worked diagram for PCl3. Lewis structure PCl3