Aluminum phosphide Lewis Structure

Aluminum phosphide Lewis Structure: AlP Lewis Structure, linear (diatomic) Geometry, sp Hybridization & Polarity

Aluminum phosphide Key Facts

The Aluminum phosphide Lewis structure is a linear diatomic with a polar bond between its two atoms; because the two atoms differ in electronegativity, Aluminum phosphide is polar.

Figure 1: Lewis Structure of Aluminum phosphide (AlP)

Chemical Formula	AlP
CAS Number	20859-73-8
Total Valence Electrons	8
Lewis Structure	linear diatomic molecule with one single bond
Electron-Domain Geometry	linear
Molecular Geometry	linear (diatomic)
Hybridization Model	sp
Bond Angle	180°
Polarity	Polar molecule

PubChem (CID 16126812) and NIST list Aluminum phosphide as AlP with CAS 20859-73-8; molecular weight ≈ 57.955300 g/mol. View CAS 20859-73-8 dictionary details on Guidechem →

Applications of Aluminum phosphide (CAS 20859-73-8)

Aluminum phosphide 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 "Aluminum phosphide" 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 20859-73-8 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Aluminum phosphide Lewis structure we first count the total valence electrons. AlP contains 3 (Al) + 5 (P); the net charge of 0 gives a total of 8 valence electrons to place.

The central atom is Al. 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 = 3 (Al) + 5 (P) = 8 electrons.

Step 2 - Lewis Structure & Electron Distribution

Place Al 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 single bond.

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

Al–P

Al: 0 lone pairs, 1 bonding domain

1 bonding domains + 0 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 Al arrange to minimize mutual repulsion, giving an linear electron-domain geometry.

Because 0 of these domains are lone pair(s) — and lone pairs repel more strongly than bonding pairs — the observed molecular geometry is linear (diatomic); the Al 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 0 lone pair(s) on Al, 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, Al uses sp hybrid orbitals to form the 2 equivalent electron-domain directions (1 bonding + 0 lone pair).

Formal-charge check

Formal charge on central Al = V − N − ½B = 3 − 0 − ½×2 = 2. The nonzero formal charge is distributed by resonance / charge separation; the drawn structure is the lowest-energy contributor.

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

Is Aluminum phosphide Polar or Nonpolar?

Aluminum phosphide is polar. The linear (diatomic) shape prevents cancellation of the bond dipoles. The bond dipoles do not cancel, leaving a net molecular dipole, which strongly influences solvation behavior and intermolecular interactions.

Expert Quote — Structural Chemistry Perspective

The decisive structural fact is not simply that the individual bonds are polar; it is whether molecular symmetry allows their vector sum to vanish. In Aluminum phosphide the linear (diatomic) arrangement prevents cancellation, so a permanent dipole remains.

Interpretation consistent with standard VSEPR / molecular-geometry references.

This polarity profile underpins its behavior as a solvent, reactant or process intermediate; when sourcing, specify grade and container compatibility.

Structural Comparison Table

Species	Formula	Central Atom	Electron Domains	Molecular Geometry	Polarity
Aluminum phosphide	AlP	Al	2	linear (diatomic)	Polar
Aluminum chloride	AlCl₃	Al	3	trigonal planar	Nonpolar

Practice question Starting from the 8 valence electrons of AlP, draw the Lewis structure and confirm the central Al 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 Aluminum phosphide (CAS 20859-73-8)? Browse Supplier on Guidechem →

FAQs

Is AlP polar or nonpolar?

Aluminum phosphide is polar. Its linear (diatomic) geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.

What is the Lewis structure of Aluminum phosphide?

linear diatomic molecule with one single bond. It uses all 8 valence electrons and the preferred structure carries a formal charge of 2 on the central atom.

What is the bond angle in Aluminum phosphide?

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

What is the hybridization of Al in Aluminum phosphide?

The conventional model is sp. Aluminum phosphide has 2 electron domains around the central Al.

What is the CAS number of Aluminum phosphide?

The CAS number is 20859-73-8. PubChem (CID 16126812) and NIST identify this with AlP; use it to locate suppliers and database records.

References

PubChem CID 16126812, Aluminum phosphide. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Aluminum phosphide. 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 Aluminum phosphide (CAS 20859-73-8).

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 20859-73-8 identifies the substance, not a universal purity specification.

Make Guideview Preferred Source on Google

Aluminum phosphide Lewis Structure