The Beryllium hydride Lewis structure is central Be bonded; the central Be has 0 electron domains (0 lone pairs), giving a tetrahedral electron-domain arrangement and a see text molecular geometry with a — bond angle. Be is best described as sp3-hybridized, and Beryllium hydride is polar because the see text shape (and/or unequal terminal atoms) prevents cancellation of the bond dipoles.
Figure 1: Lewis Structure of Beryllium hydride (BeH2)
| Chemical Formula | BeH2 |
| CAS Number | 7787-52-2 |
| Total Valence Electrons | 4 |
| Lewis Structure | central Be bonded |
| Electron-Domain Geometry | tetrahedral |
| Molecular Geometry | see text |
| Hybridization Model | sp3 (central Be) |
| Bond Angle | — |
| Polarity | Polar molecule |
Beryllium hydride 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.
To draw the Beryllium hydride Lewis structure we first count the total valence electrons. BeH2 contains 2 (Be) + 2×1 (H); the net charge of 0 gives a total of 4 valence electrons to place.
The central atom is Be. 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).
Total valence electrons = 2 (Be) + 2×1 (H) = 4 electrons.
Place Be 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: central Be bonded; no lone pairs on Be.
Counting bonding and nonbonding electrons around Be therefore satisfies the octet/expanded-octet requirement for the drawn structure.
VSEPR theory states that the 0 electron domains around Be arrange to minimize mutual repulsion, giving an tetrahedral 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 see text; the Be bond angle is set to — rather than the ideal value for the electron-domain geometry.
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 Be, the lone-pair domains occupy positions that minimize overall repulsion while pushing the bonding domains (and therefore the bonded atoms) closer together.
In the conventional localized-bond model, Be uses sp3 hybrid orbitals to form the 0 equivalent electron-domain directions (0 bonding + 0 lone pair).
Formal charge on central Be = V − N − ½B = 2 − 0 − ½×0 = 2. The nonzero formal charge is distributed by resonance / charge separation; the drawn structure is the lowest-energy contributor.
Beryllium hydride is polar. The see text 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.
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 Beryllium hydride the see text 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.
| Species | Formula | Central Atom | Electron Domains | Molecular Geometry | Polarity |
|---|---|---|---|---|---|
| Beryllium hydride | BeH2 | Be | 0 | see text | Polar |
| Beryllium chloride | BeCl2 | Be | 2 | linear | Nonpolar |
Beryllium hydride is polar. Its see text geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.
central Be bonded; no lone pairs on Be. It uses all 4 valence electrons and the preferred structure carries a formal charge of 2 on the central atom.
The Be angle is about —. Lone-pair repulsion compresses the angle from the ideal tetrahedral value.
The conventional model is sp3. Beryllium hydride has 0 electron domains around the central Be.
The CAS number is 7787-52-2. PubChem (CID 139073) and NIST identify this with BeH2; use it to locate suppliers and database records.
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 7787-52-2 identifies the substance, not a universal purity specification.
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