Diphosphorus Lewis Structure

Diphosphorus Lewis Structure: P₂ Lewis Structure, linear (diatomic) Geometry, sp Hybridization & Polarity

Diphosphorus Key Facts

The Diphosphorus Lewis structure is a linear diatomic with a nonpolar bond between its two atoms; because the two atoms are identical, Diphosphorus is nonpolar.

Figure 1: Lewis Structure of Diphosphorus (P₂)

Chemical Formula	P₂
CAS Number	12185-09-0
Total Valence Electrons	10
Lewis Structure	linear diatomic molecule with one triple bond and a lone pair on each atom
Electron-Domain Geometry	linear
Molecular Geometry	linear (diatomic)
Hybridization Model	sp
Bond Angle	180°
Polarity	Nonpolar molecule

PubChem (CID 5460700) and NIST list Diphosphorus as P ₂ with CAS 12185-09-0; molecular weight ≈ 61.94752400 g/mol. View CAS 12185-09-0 dictionary details on Guidechem →

Applications of Diphosphorus (CAS 12185-09-0)

Diphosphorus is encountered as a reagent, intermediate or specialty chemical in inorganic, organometallic and materials synthesis. Confirm grade, purity and supplier documentation (SDS) before specifying for a process.

Reagent / Intermediate Used in synthesis and formulation where the substance's reactivity is required.

Specialty Chemical Specified by grade for the intended process or research use.

Sourcing Verify purity, package and regional availability via the CAS identifier.

Procurement Note "Diphosphorus" is supplied in multiple commercial grades and package sizes. Specify purity, grade, moisture/impurity limits, package (cylinder, drum or bulk) and intended process, and use CAS 12185-09-0 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Diphosphorus Lewis structure we first count the total valence electrons. P₂ contains 2×5 (P); the net charge of 0 gives a total of 10 valence electrons to place.

The central atom is P. It is the least electronegative atom capable of forming multiple bonds and is surrounded by the more electronegative terminal atom(s); hydrogen, when present, always occupies a terminal position. Electronegativity considerations place the electron density toward the terminal atom(s).

Valence-electron count

Total valence electrons = 2×5 (P) = 10 electrons.

Step 2 - Lewis Structure & Electron Distribution

Place P at the center and connect each surrounding atom with a single bond, complete octets on the terminal atoms, and place any remaining electrons on the central atom. The resulting electron distribution is: linear diatomic molecule with one triple bond and a lone pair on each atom.

Counting bonding and nonbonding electrons around P therefore satisfies the octet/expanded-octet requirement for the drawn structure.

P–X

P: 1 lone pair, 1 bonding domain

1 bonding domains + 1 lone pairs = 2 electron domains

Octet & Diradical Note In a simple Lewis drawing each atom of this homonuclear diatomic carries lone pairs; species such as O₂ are more accurately described by molecular-orbital theory (paramagnetism arises from unpaired electrons in π* orbitals).

Step 3 - VSEPR Theory & Geometry

VSEPR theory states that the 2 electron domains around P arrange to minimize mutual repulsion, giving an linear electron-domain geometry.

Because 1 of these domains are lone pair(s) — and lone pairs repel more strongly than bonding pairs — the observed molecular geometry is linear (diatomic); the P bond angle is set to 180° rather than the ideal value for the electron-domain geometry.

Repulsion hierarchy

A useful VSEPR approximation is: lone pair–lone pair repulsion > lone pair–bonding pair repulsion > bonding pair–bonding pair repulsion. With 1 lone pair(s) on P, the lone-pair domains occupy positions that minimize overall repulsion while pushing the bonding domains (and therefore the bonded atoms) closer together.

Hybridization & Formal Charge

In the conventional localized-bond model, P uses sp hybrid orbitals to form the 2 equivalent electron-domain directions (1 bonding + 1 lone pair).

Formal-charge check

Formal charge on central P = V − N − ½B = 5 − 2 − ½×6 = 0. The preferred Lewis structure carries zero formal charge on the central atom (and on the terminals), so it is the dominant contributor.

Modeling Note Modeling Note: sp is a compact model for the 2 electron-domain directions around P; full quantum-chemical treatments use molecular orbitals.

Is Diphosphorus Polar or Nonpolar?

Diphosphorus is nonpolar. Although individual P–terminal bonds are polar when the atoms differ in electronegativity, the linear (diatomic) geometry makes their vector sum zero, so there is no net molecular dipole.

Expert Quote — Structural Chemistry Perspective

A common misconception is that polar bonds guarantee a polar molecule. Diphosphorus shows the opposite: identical bond dipoles arranged with linear (diatomic) symmetry cancel exactly, yielding a nonpolar species.

Interpretation consistent with standard VSEPR / molecular-geometry references.

Its nonpolar character governs solvation and intermolecular behavior; specify grade and handling when sourcing.

Structural Comparison Table

Species	Formula	Central Atom	Electron Domains	Molecular Geometry	Polarity
Diphosphorus	P₂	P	2	linear (diatomic)	Nonpolar
Phosphine	H₃P	P	4	trigonal pyramidal	Polar
Phosphorus trichloride	Cl₃P	P	4	trigonal pyramidal	Polar
Phosphorus pentachloride	Cl₅P	P	5	trigonal bipyramidal	Nonpolar
Phosphorus trifluoride	F₃P	P	4	trigonal pyramidal	Polar
Phosphorus pentafluoride	F₅P	P	5	trigonal bipyramidal	Nonpolar

Practice question Starting from the 10 valence electrons of P₂, draw the Lewis structure and confirm the central P atom is sp-hybridized with linear (diatomic) geometry. What happens to the bond angle if one terminal atom is replaced by a more electronegative substituent?

Looking for industrial bulk or specified-grade supplies of Diphosphorus (CAS 12185-09-0)? Browse Supplier on Guidechem →

FAQs

Is P₂ polar or nonpolar?

Diphosphorus is nonpolar. Its linear (diatomic) symmetry cancels the bond dipoles exactly.

What is the Lewis structure of Diphosphorus?

linear diatomic molecule with one triple bond and a lone pair on each atom. It uses all 10 valence electrons and the preferred structure carries zero formal charge on the central atom.

What is the bond angle in Diphosphorus?

The P angle is about 180°. Lone-pair repulsion compresses the angle from the ideal linear value.

What is the hybridization of P in Diphosphorus?

The conventional model is sp. Diphosphorus has 2 electron domains around the central P.

What is the CAS number of Diphosphorus?

The CAS number is 12185-09-0. PubChem (CID 5460700) and NIST identify this with P₂; use it to locate suppliers and database records.

References

PubChem CID 5460700, Diphosphorus. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Diphosphorus. Formula, CAS Registry Number and thermochemical / spectroscopic data.
IUPAC Gold Book. Definitions for "lone pair", "VSEPR", "hybridization" and "formal charge".
Atkins, P. & de Paula, J., Physical Chemistry. VSEPR, molecular geometry and dipole moments.
Guidechem supplier & dictionary records. Commercial sourcing and CAS-linked property pages for Diphosphorus (CAS 12185-09-0).

Technical scope: Lewis structures, VSEPR and hybridization are model-based descriptions for chemical communication and structure prediction; actual molecular electronic structure is more accurately represented by molecular-orbital and quantum-chemical methods. Commercial grades vary substantially by supplier and intended use; CAS 12185-09-0 identifies the substance, not a universal purity specification.

Make Guideview Preferred Source on Google

Diphosphorus Lewis Structure