Chemical Bond Simulator
Visualise ionic, covalent & metallic bonding with animated models — 53 real substances, 37 elements
Select two elements — or an element and a polyatomic ion — then click Test Bond. The reaction engine checks if they can form an ionic or covalent compound.
⚛ Polyatomic ions
A polyatomic ion is a group of atoms covalently bonded to each other that carries one charge and travels as one unit. Treat NO3− as a single thing with a charge of 1−, exactly like Cl−, and every formula works the same way.
Chemical Bonds Quiz
Test your knowledge of ionic and covalent bonding with 5 randomised questions covering bond types, valence electrons, electron transfer and sharing, and compound identification.
1 Overview
This simulator shows how atoms form chemical bonds using the Bohr atomic model. You can visualise all three bond types: ionic (electron transfer between a metal and a nonmetal), covalent (electron sharing between nonmetals) and metallic (a lattice of cations in a shared sea of delocalised electrons). The tool includes 39 preset compounds plus 14 metals and alloys (15 covalent + 24 ionic), a reaction engine covering 37 elements, and an 18-question quiz bank.
2 Simulate Mode
- Left panel — Build a Compound: Select any two elements from the 37-element grid (metals gold, non-metals teal, noble gases purple, metalloids grey). Click ⚗ Test Bond to validate and auto-launch the Bohr model animation.
- Polyatomic ions: Open the ⚛ Polyatomic ions tray under the element grid for the nine groups a course needs — hydroxide, nitrate, sulfate, carbonate, hydrogencarbonate, phosphate, ammonium, permanganate and dichromate. Put one in either slot exactly as you would an element: Ca + NO3− gives Ca(NO3)2, NH4+ + SO42− gives (NH4)2SO4. On the canvas each one is drawn as its actual structure — the atoms, the covalent bonds between them, inside square brackets with the charge outside — because that is what it is: a group of atoms acting as a single ion. Every bond is drawn the same, since resonance makes nitrate’s three N–O bonds identical; lone pairs are deliberately left off, because sulfate and phosphate have no single agreed Lewis form and a simulator should not contradict your marking scheme. Tetrahedral ions are drawn flat, so the angles you see are a projection — the readout says so. Each one also shows where its charge comes from: N(5) + 3 × O(6) = 23 valence electrons, the group holds 24, and that extra electron is the 1−.
- Pairs that form more than one compound: Many do. Carbon and oxygen give both CO₂ and CO; iron and chlorine give FeCl₃ and FeCl₂; phosphorus and chlorine give PCl₃ and PCl₅. When a pair has several products, a row of formula buttons appears under the result — click one to redraw that compound. This is the reason Greek prefixes (mono-, di-, tri-, tetra-, penta-, hexa-) and Roman numerals (Stock notation) exist: without them, “carbon oxide” and “iron chloride” name nothing in particular.
- Right panel — Preset substances: Choose a bond type (Covalent / Ionic / Metallic) and pick from the tabs, then click ▶ Simulate. The row names what it is offering, because the three are not the same kind of thing: covalent gives you molecules (H&sub2; and O&sub2; are elements, not compounds), ionic gives you compounds, and metallic gives you a metal or alloy. A pure metal belongs there on its own: metallic bonding happens inside one element — Na⁺ cores sitting in a sea of their own delocalised electrons — so unlike an ionic or covalent bond it needs no second species. The nine pure metals and the five alloys are shown as two separate groups, and an alloy is not a compound: it is a mixture with no fixed ratio, which is why it is written Cu + Zn rather than CuZn.
- Metallic — the third bond type: Nine pure metals and five alloys, and every alloy’s host metal is offered on its own — you cannot show solder freezing below both its metals without both metals. A metal is not two species meeting, so it is drawn as one lattice: cations in a shared sea of delocalised electrons. Simulate MAKES it. Pick an alloy and you watch it being made — two separate blocks of cold metal on a hearth, the fire lit, the atoms vibrating harder as the temperature climbs, the host melting so the two pools run together, and then a crystallisation front sweeping across as every atom locks onto a lattice site with the guest built in (in steel the carbon sits in the gaps; solder, a eutectic, freezes into two separate solids). Watch the temperature STALL at the melting point: that energy is latent heat breaking the lattice apart, not raising the temperature. Once the metal exists, an Its properties row appears under the buttons — Electron sea, Conduction (a voltage makes the whole sea drift, which is why a metal conducts as a solid) and Malleability (the planes slide in a pure metal and JAM in an alloy — that jam is why alloys are harder). Each starts the moment you click it and keeps running until you click it again.
- °C or °F: the SI / Imperial switch sits beside Reset, and your choice follows you to every other simulator on the site. It converts temperature — every melting and freezing point, the forge thermometer, and each sentence that quotes one. It deliberately leaves conductivity in MS/m, latent heat in kJ/mol and bond length in picometres: the US convention for conductivity is % IACS, a materials-engineering unit no chemistry syllabus uses, every US chemistry text writes kJ/mol, and picometres are universal for bond lengths. Changing the unit of a number a student is meant to recognise would make it harder to read, not easier.
- Ionic set — Simple / With polyatomic ions: Under Ionic a second row appears offering two sets: the simple binary compounds (NaCl, MgO…) and those built from a polyatomic ion (NaOH, CaCO3, CuSO4, Ca(NO3)2…). Both sets are ionic — this is a filter, not a third kind of bonding, which is why the row only exists under Ionic and never under Covalent. On the canvas those compounds carry a line saying which bond is where: covalent bonds INSIDE the ion, ionic attraction BETWEEN the ions.
- After the animation, the Info Panel shows electron counts, bond data, and real-world facts.
- ▶ Explain: once Simulate has made the substance, an Explain button appears at the bottom-left of the canvas. Press it and a teacher works through it step by step, handwritten on the canvas over the simulator’s own picture: counting the outer electrons, what each atom wants for stability, the sharing or the transfer, counting again, then the shape and polarity of a molecule, the charges and the formula of an ionic compound, or the electron sea and the forge for a metal or alloy. It moves on by itself; pause, step back or forward with the controls under it (or Space and the arrow keys), and Esc closes it. It handles the cases simple counting gets wrong: carbon monoxide’s third pair is dative (both electrons from oxygen), and CN and NO are radicals with one unpaired electron. Only molecules whose Lewis structure syllabi disagree on (SO2, SO3, SeO2) are deliberately not explained.
- 3D view: once Simulate has made a covalent molecule, the 3D view button appears beside Explain and swaps the Bohr picture for a ball-and-stick model at its real shape: methane’s 109.5° tetrahedron, ammonia’s pyramid, water bent at 104.5°, with the lone pairs drawn as purple lobes. Drag to rotate it, press L to cycle the lone pairs (central atom, all atoms, off), and press the button again to go back to the 2D view. Inside the 3D view, Orbitals switches to the valence-bond picture: the central atom’s hybridisation (sp, sp² or sp³), one σ bond along each bond axis (teal), and each extra pair of a double or triple bond as a π bond (orange) above and below the axis. CO2 shows its two π bonds at right angles; N2 shows one σ and two π. Molecules with five or six electron domains get no hybridisation label, since sp³d and sp³d² are no longer taught as real. Angles shows each bond angle at the central atom as an arc drawn in the plane of its two bonds, one arc per distinct angle (one for methane’s 109.5°, two for PCl5’s 90° and 120°). Measured angles are printed plainly and ideal ones are marked “ideal”; where lone pairs squeeze an angle, the ideal value is shown beneath it, as in water’s 104.5° (ideal 109.5°). For an ionic compound the 3D view shows a piece of the crystal instead of a molecule: its real room-temperature structure: one cubic unit cell for rock salt (NaCl, MgO), zinc blende (ZnS), fluorite (CaF2), antifluorite (Na2O), cuprite (Cu2O) and anti-ReO3 (Cu3N), and a small block of cells for wurtzite (ZnO), rutile (SnO2, MgF2), the layered CdI2 and CdCl2 types (MgCl2, PbI2), corundum (Al2O3) and red PbO, with the ions drawn to their relative sizes. One ion is ringed and its nearest neighbours are highlighted, including any just outside the cell, so you can count them: 6 around each ion in rock salt, 8 around Ca2+ and 4 around F− in fluorite. The Centre button switches between the two ions. There are no molecules, only a repeating lattice; for unit cells and atom counting in depth, use the Build Your Crystal simulator. Compounds whose real structure is too complex to show honestly in one small cell (CaCl2, PbCl2, CuO, Mg3N2), formulas that are not real ionic solids, and salts of polyatomic ions have no 3D view. For a metal the 3D view shows its real crystal structure (face-centred cubic copper and aluminium, body-centred cubic iron and sodium, hexagonal magnesium and zinc, white tin) with the sea of delocalised electrons drifting through the whole block rather than around any one atom. Neighbours rings one atom and highlights the atoms touching it: 12 in a close-packed metal, 8 in a body-centred one, 6 + 6 in zinc, whose hexagonal lattice is stretched; Sea shows or hides the electrons. The catalogued alloys show where the second element goes: zinc on copper’s own sites in brass (about 29 atoms in 100), carbon in the gaps between iron atoms in steel, and solder as two separate solids, tin-rich and lead-rich, side by side. An alloy built from two metals you pick has no 3D view, because whether that pair actually mixes depends on its phase diagram. Bond lengths are measured values where known; otherwise they’re estimated from covalent radii, and the caption says so.
- 📷 Export: Click the Export button (or right-click the canvas) to save the current frame as a PNG image.
- 🔊 Sound: Click the speaker icon to mute / unmute the bond-formation sound effects. Right-click the canvas to toggle the background grid.
3 Explore Mode
Browse educational cards about bonding concepts across five tabs: Overview (what bonds are, valence electrons, electronegativity, Bohr model), Covalent (single/double/triple bonds, polarity, lone pairs), Ionic (transfer mechanism, charge balance, crystal properties), Metallic (the electron sea, how many electrons each atom gives, why metals conduct and bend, substitutional and interstitial alloys), and Comparison (formation, physical properties, conductivity, examples across all three types).
4 Quiz Mode
5 randomised multiple-choice questions per round drawn from a pool of 18. Topics include bond type identification, valence electrons, electron transfer, electronegativity, and metallic bonding and alloys. Each answer shows a detailed explanation. The result screen colour-codes correct (✓) and incorrect (✗) answers so you know exactly what to review. Score 5/5 for ★★★.
Free Online Chemical Bond Simulator — Ionic & Covalent Bonding Visualised
This free chemistry simulator animates ionic and covalent bond formation using live Bohr atomic models, and metallic bonding as a lattice of cations in a shared electron sea. Watch electrons transfer, share or delocalise in real time, build your own compounds from 37 elements, and test your knowledge with an interactive quiz — no login, no download, works on any device.
Why Do Atoms Form Chemical Bonds?
Atoms bond because doing so lowers their total energy and produces a more stable electron configuration. Most atoms aim to fill their outermost shell with 8 electrons — the octet rule — mimicking the stable configuration of noble gases like neon and argon. Hydrogen is the exception: its first shell holds only 2 electrons (the duet rule), so H₂, HCl, and H₂O all satisfy hydrogen with just 2 electrons.
What Is the Difference Between Ionic and Covalent Bonds?
The key difference is what happens to the electrons. In an ionic bond, a metal atom gives one or more electrons entirely to a nonmetal, creating oppositely charged ions that attract each other electrostatically (e.g., Na⁺ and Cl⁻ in table salt). In a covalent bond, two nonmetals share electrons equally or unequally, keeping the pair between both nuclei (e.g., the O–H bonds in water). Ionic compounds are typically hard crystalline solids with high melting points; covalent compounds are often gases, liquids, or soft solids at room temperature.
How Does Electronegativity Determine Bond Type?
Electronegativity (EN) measures how strongly an atom pulls electrons toward itself. The difference in EN between two bonded atoms gives a useful guideline for bond type — though it is a guideline, not an absolute law (HF with EN diff 1.78 is a well-known covalent exception):
| EN Difference | Bond Type | Example | Character |
|---|---|---|---|
| > 1.7 | Ionic | NaCl (2.23), LiF (3.00) | Full electron transfer → ions formed |
| 0.5 – 1.7 | Polar Covalent | H₂O (1.24), HCl (0.96) | Unequal sharing → δ+/δ− dipole |
| < 0.5 | Nonpolar Covalent | H₂ (0.00), CH₄ (0.35) | Equal sharing → no dipole |
Fluorine (EN 3.98) is the most electronegative element; caesium (EN 0.79) is the least. The simulator highlights the EN difference for every compound and flags whether the bond is nonpolar, polar, or fully ionic.
What Are Single, Double, and Triple Covalent Bonds?
Bond order is the number of shared electron pairs between two atoms. More shared pairs means a shorter, stronger, and harder-to-break bond:
| Bond Order | Shared Pairs | Example | Bond Energy |
|---|---|---|---|
| Single | 1 pair (2 e⁻) | H₂, HCl, H₂O | ~200–500 kJ/mol |
| Double | 2 pairs (4 e⁻) | O₂, CO₂ | ~500–800 kJ/mol |
| Triple | 3 pairs (6 e⁻) | N₂ (945 kJ/mol) | ~800–1000 kJ/mol |
Why Do Ionic Compounds Conduct Electricity When Dissolved?
In solid form, ionic compounds lock their ions into a rigid crystal lattice — the ions cannot move, so no electric current flows. When dissolved in water or melted, the lattice breaks apart and the free ions (e.g., Na⁺ and Cl⁻) migrate through the solution, carrying charge and conducting electricity. This is why NaCl solution (saline) conducts, but solid NaCl does not. The simulator animates this electron-transfer process step by step so you can see exactly which electrons move and why.
How Does the Bohr Model Visualise Chemical Bonding?
The Bohr model (1913) places electrons in discrete shells around the nucleus: shell 1 holds 2 electrons, shell 2 holds 8, shell 3 holds up to 18. While modern quantum mechanics describes electron probability clouds rather than fixed orbits, the Bohr model remains the gold standard for teaching bonding because it makes valence electrons, electron transfer, and electron sharing visually obvious. Every element in this simulator is rendered as a real-time animated Bohr model — you can watch valence electrons leave the sodium atom and arrive on the chlorine atom, or see shared electron pairs oscillating between two oxygen nuclei in O₂.
How to Use This Chemical Bond Simulator
- Preset Simulate mode — select Covalent, Ionic or Metallic, choose a substance (H₂, NaCl, Cu + Zn…), click Simulate and watch the full animated sequence — the Bohr models for a compound, the forge for an alloy.
- Build a Compound — pick any two of 37 elements from the periodic grid and click Test Bond. The built-in reaction engine checks valence electrons, electronegativity, and element types; it either launches the animation or explains exactly why it cannot — a noble gas, two ions of the same charge, a giant covalent structure such as silicon dioxide rather than a molecule, or a pair that balances on paper but gives no stable compound. Where a pair forms several compounds the engine offers all of them — 286 in total across the grid, plus 162 more once the polyatomic-ion tray is open; any two metals give a metal or an alloy.
- Explain — after a simulation, press the Explain button on the canvas for a step-by-step, handwritten walkthrough of why the substance forms the way it does: electron counts, stability, shape, polarity, charges and the formula.
- Explore mode — read concept cards on bonding fundamentals, polarity, lone pairs, and property comparisons.
- Quiz mode — answer 5 randomised questions from an 18-question bank; get instant feedback and a colour-coded result card showing what to review.
Why Do the Same Two Elements Form Different Compounds?
Because the octet rule is a starting point, not the whole story. Two separate mechanisms make one pair of elements give several compounds, and this simulator models both.
Variable oxidation states. Most metals have one charge — sodium is always Na⁺, magnesium always Mg²⁺. Transition and post-transition metals do not. Iron forms both Fe²⁺ and Fe³⁺, so it gives both FeCl₂ and FeCl₃, and both FeO and Fe₂O₃. That is precisely why Stock notation — the Roman numeral in iron(II) chloride — is required: the name has to say which one. The simulator carries the real stable states for copper, iron, manganese, cobalt, chromium, tin and lead, and shows the correct electron transfer for each. It does not offer states that exist only on paper: manganese(IV) is real as MnO₂ — the oxidant in a dry cell and the catalyst for hydrogen peroxide decomposition — but there is no MnCl₄.
Expanded octets and dative bonds. Two nonmetals can share in more than one ratio. Phosphorus, in period 3, can hold ten electrons, so it forms PCl₃ (octet-obeying) and PCl₅ (expanded); sulfur can hold twelve, giving SF₆. Nitrogen and oxygen, one period up, cannot — there is no NCl₅. And carbon monoxide exists at all only because oxygen donates a third electron pair on its own, a dative or coordinate bond, giving the C≡O triple bond that is the strongest bond known in any molecule at 1072 kJ/mol. No octet arithmetic predicts CO; you have to be told.
Historically this is Dalton’s law of multiple proportions: when two elements form more than one compound, the masses combining with a fixed mass of the other are in small whole-number ratios — which was among the first real evidence that matter is made of atoms.
What Is a Polyatomic Ion?
A polyatomic ion is a group of atoms held together by covalent bonds that carries a single charge and behaves as one unit. Nitrate, NO3−, is one nitrogen and three oxygens sharing electrons with each other — and the whole group, not any one atom, carries the 1−. Once you accept that, every formula you already know still works: nitrate substitutes for chloride wherever Cl− would go.
The one thing that changes is how you write it. NaCl needs no brackets and neither does NaNO3, because there is one of each. But calcium is Ca2+, so it needs two nitrates — and “CaNO32” would say three oxygens and thirty-two of something. The brackets in Ca(NO3)2 say the subscript applies to the whole group: one calcium, two nitrogens, six oxygens. Same rule for Al2(SO4)3, Ca3(PO4)2 and (NH4)2SO4.
Ammonium is the odd one. It is the only common positive polyatomic ion, and the only cation in ordinary school chemistry that is not a metal. Ammonia, NH3, has a lone pair on nitrogen; that lone pair grabs a fourth hydrogen and supplies both electrons for the new bond — a dative bond — leaving the group one electron short overall. NH4+ then behaves exactly like a group 1 ion in every formula it appears in.
This is why the simulator puts them in a sub-set of Ionic rather than a third Bond Type pill. A polyatomic ion is a kind of ion, not a kind of bond; every compound containing one is ionic, and a control offering “Covalent / Ionic / Polyatomic” as three peers would teach the opposite. The third bond type is metallic.
One consequence the simulator shows honestly: when a metal meets a polyatomic ion, electrons really do transfer — a calcium atom becomes Ca2+. When two ions meet, as in ammonium sulfate, nothing transfers at all. Both units already carry their charges and simply attract, and the animation says so rather than inventing an electron hand-over that does not happen.
What Is Metallic Bonding, and What Is an Alloy?
A metal is not two different atoms joined together. Every atom gives its outer electrons to a shared sea that belongs to no single one of them, leaving a lattice of positive cores held together by their attraction to it. Three consequences follow directly, and the simulator shows each: metals conduct as solids (the sea drifts when a voltage is applied, while ionic compounds only conduct once molten or dissolved); they bend rather than shatter (the bonding has no direction, so planes of atoms slide and the sea simply follows); and the more electrons each atom contributes, the stronger the pull — sodium gives one and melts at 98 °C, magnesium gives two and melts at 650, aluminium gives three and melts at 660.
An alloy is not a compound. There is no fixed ratio, no formula and no electron transfer — which is why the simulator writes brass as Cu + Zn and never as CuZn. What changes is the lattice: in a substitutional alloy the guest atoms take the host’s own sites (zinc in copper), and in an interstitial one they are far too small for that and sit in the gaps (carbon in iron, which is steel). Either way the planes can no longer slide cleanly past each other, and that is the whole reason an alloy is harder than the metals it is made from.
Making one is a thermal process, and the simulator runs it properly. The two metals start separate and cold. Heat goes in and the temperature climbs to the melting point of the host — then it stops, while the energy still going in is absorbed as latent heat of fusion (13.26 kJ/mol for copper) breaking the lattice apart rather than raising the temperature. The guest dissolves into the liquid; it does not need to melt itself. Then it cools and freezes — starting below the host’s own melting point, because a dissolved guest depresses the freezing point, and, unlike a pure metal, setting over a range of temperature rather than at one. Solder is the exception that proves the rule: 63 % tin with 37 % lead freezes all at once at 183 °C, below tin’s 232 and lead’s 327, into fine interleaved plates of two solids — one rich in tin, one rich in lead. That is a eutectic.
3D Molecular Geometry Simulator — VSEPR Shapes and Bond Angles
Once Simulate has made a covalent molecule, press 3D view on the canvas to turn the flat Bohr picture into a rotatable 3D molecule model: ball-and-stick atoms at their real VSEPR geometry, with each lone pair drawn as a purple electron cloud and each bonding pair as a teal cloud, two electrons moving inside every cloud. Drag to rotate it. The 3D view works for every covalent molecule the simulator can make, including the ones you build yourself in Build a Compound, not just the presets.
VSEPR (valence-shell electron-pair repulsion) theory says the electron pairs around a central atom spread out as far apart as they can. Count the bonded atoms and the lone pairs on the central atom, and the shape follows. Lone pairs push harder than bonding pairs, which is why water is bent at 104.5° rather than the ideal tetrahedral 109.5°, and ammonia is a trigonal pyramid at 107°. Press Angles to see each bond angle drawn as an arc between its two bonds. Measured angles are printed as they are; where no measured value is used, the angle is marked “ideal”, and where lone pairs squeeze an angle the ideal value is shown beneath it.
| Molecule | Shape (VSEPR) | Bond angle | Lone pairs on central atom | Central-atom hybridization | Bonds |
|---|---|---|---|---|---|
| CO2 | linear | 180° | 0 | sp | 2 σ + 2 π |
| BF3 | trigonal planar | 120° | 0 | sp2 | 3 σ |
| CH4 | tetrahedral | 109.5° | 0 | sp3 | 4 σ |
| NH3 | trigonal pyramidal | 107° | 1 | sp3 | 3 σ |
| PCl3 | trigonal pyramidal | 100° | 1 | sp3 | 3 σ |
| H2O | bent | 104.5° | 2 | sp3 | 2 σ |
| H2S | bent | 92° | 2 | almost pure p | 2 σ |
| PCl5 | trigonal bipyramidal | 90° and 120° | 0 | not labelled | 5 σ |
| SF6 | octahedral | 90° | 0 | not labelled | 6 σ |
| N2 | linear (diatomic) | — | 1 on each N | — | 1 σ + 2 π |
Bond lengths in the 3D view are measured gas-phase values where they are known and are marked ≈ where they are estimated from covalent radii.
Hybridization, Sigma and Pi Bonds in 3D
Inside the 3D view, Orbitals switches to the valence-bond picture. The central atom is labelled with its hybridization from its number of electron domains: two give sp (linear), three give sp2 (trigonal planar) and four give sp3 (tetrahedral). Every bond is one sigma (σ) bond, drawn as a teal cloud along the line between the two nuclei. Each extra pair in a double or triple bond is a pi (π) bond, drawn as two orange lobes above and below that line, because a π bond is made by p orbitals overlapping side by side. CO2 shows its two π bonds at right angles to each other, and N2 shows one σ and two π.
Three cases are deliberately handled with care. Molecules with five or six electron domains, such as PCl5 and SF6, get no sp3d or sp3d2 label, because d orbitals take almost no part in their bonding and current courses no longer teach those labels. H2S, PH3 and H2Se have measured angles near 90°, which shows their bonds use almost pure p orbitals, so they are not called sp3. And SO2, SO3 and SeO2, whose double-bonded Lewis structures would put ten electrons around the central atom, get no σ/π picture at all, because textbooks disagree on how to draw them.
Ionic Compounds in 3D — Why NaCl Is a Lattice, Not a Molecule
An ionic compound has no molecules. Press 3D view after simulating one and the canvas shows a piece of its ionic lattice: the real room-temperature crystal structure, with the ions drawn to their relative sizes. One ion is ringed and its nearest neighbours of opposite charge are highlighted, including any that sit just outside the drawn cell, so you can count the coordination number yourself. In sodium chloride every Na+ touches 6 Cl− and every Cl− touches 6 Na+; the formula NaCl only states the 1 : 1 ratio. The Centre button switches between the two ions.
| Structure | Coordination | Examples |
|---|---|---|
| rock salt | 6 : 6 | NaCl, KCl, MgO, CaO, AgCl, NiO |
| zinc blende | 4 : 4 | ZnS, ZnSe, CuCl, CuI |
| wurtzite | 4 : 4 | ZnO, BeO, CdS, AlN |
| fluorite | 8 : 4 | CaF2, SrF2, BaF2 |
| antifluorite | 4 : 8 | Li2O, Na2O, K2S |
| rutile | 6 : 3 | SnO2, MgF2, MnO2 |
| CdI2 and CdCl2 layers | 6 : 3 | MgCl2, PbI2, CdCl2, NiCl2 |
| corundum | 6 : 4 | Al2O3, Cr2O3, Fe2O3 |
| cuprite | 2 : 4 | Cu2O, Ag2O |
Only compounds with a well-established structure are drawn. Salts of polyatomic ions, compounds whose real structure is too complex for one small cell (CaCl2, PbCl2, CuO) and formulas that are not real ionic solids have no 3D view rather than a guessed lattice. To count atoms in a unit cell, compare face-centered and body-centered cubic packing, or build a crystal yourself, use the Build Your Crystal Simulator; to see the electron shells of each atom first, use Build an Atom.
Can I see molecules in 3D?
Yes. After Simulate has made any covalent molecule, press 3D view on the canvas to rotate a ball-and-stick model at its real VSEPR shape, with lone pairs and bonding pairs drawn as electron clouds. Orbitals shows hybridization with sigma and pi bonds, and Angles draws every bond angle. Ionic compounds open as a 3D crystal lattice instead.
What is the bond angle of water, and why is it not 109.5°?
Water's H–O–H bond angle is 104.5°. Oxygen has four electron pairs, two bonding and two lone pairs, arranged roughly tetrahedrally, which alone would give 109.5°. Lone pairs repel more strongly than bonding pairs, so they squeeze the two O–H bonds closer together and the molecule is bent at 104.5°.
Is NaCl made of molecules?
No. Sodium chloride is an ionic lattice: every Na+ ion is surrounded by 6 Cl− ions and every Cl− by 6 Na+, repeating in all directions. There is no separate NaCl molecule; the formula only gives the 1 : 1 ratio of the ions.
Curriculum Alignment — GCSE, A-Level, AP & IB Chemistry
This simulator directly supports the chemical bonding topic across major curricula: GCSE Chemistry (ionic and covalent bonding, formulae of ionic compounds including polyatomic ions, properties of ionic compounds), A-Level Chemistry (electronegativity, bond polarity, lattice energy, molecular shapes), AP Chemistry (Unit 2: Molecular and Ionic Compound Structure, bond order and energy, expanded octets, polyatomic-ion nomenclature, metallic bonding and alloys), and IB Chemistry (Topic 4: Chemical Bonding and Structure). Teachers can use the live canvas in class as an animated alternative to static diagrams, and students can self-study at home or on a tablet with no installation required.
Who Uses This Chemistry Simulator?
Students at GCSE, A-Level, AP, IB, and vocational (BTEC/TVET) level use it to visualise content that is abstract in textbooks. Chemistry teachers use it as a projected demonstration — the full-screen canvas and step-by-step animation replace printed diagrams in lessons on ionic bonding, covalent bonding, and electronegativity. Tutors use the Build-a-Compound engine to challenge students with unfamiliar element pairs. Self-learners preparing for resit exams use the quiz to identify knowledge gaps quickly. The tool is completely free, requires no account, and works on desktop, laptop, and iPad.
Explore Related Free Chemistry & Science Simulators
Deepen your chemistry and physics knowledge with other free simulators on MechSimulator. Then write and balance the reactions those bonds take part in with the free balancing chemical equations game, where every atom visibly moves from the reactants to the products. Test acid and alkali reactions with the Litmus Paper Test Virtual Lab. Explore how gases behave under pressure and temperature with the Boyle’s Law Simulator, Charles’ Law Simulator, and Ideal Gas Law Simulator. Understand heat flow with the Heat Transfer Simulator, or explore electrical fundamentals with the Ohm’s Law Simulator. All tools are free, browser-based, and require no signup or installation. To see how bonded atoms stack into a crystal, open the Build Your Crystal Simulator (unit cells, rock salt, caesium chloride and metallic lattices). Then see redox reactions drive an electric current in the Galvanic & Electrolytic Cell Virtual Lab.
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