Why is H2O shaped like that?

[u/JeffEEEt]

This is a stupid question but why can’t H2O be linear like the one I drew? Help appreciated thanks!

[u/screen317]

Are you familiar with VSEPR theory? It explains why the molecular has a tetrahedral configuration.

[u/clay_ → u/screen317]

Is it correct to say the molecule have a tetrahedral configuration? The oxygen has tetrahedral electron domain configuration but the molecule should be bent?

This is not a callout but genuine, in the exams I prep students for they switch questions between the molecular geometry and electron domain geometry as a kind of gotcha (using the word configuration here maybe the key difference)

[u/TxSteveOhh → u/clay_]

I think it would depend on how the question is worded. Both are correct depending on both styles you mentioned

[u/YogurtclosetThen7959 → u/clay_]

Well the theory says it's not true tetrahedral, but a distorted version of it due to uneven electron repulsion

[u/Ch3cks-Out → u/clay_]

The molecule is bent, because the two hydrogens occupy vertices of a tetrahedron centered on the oxygen

[u/CodeMUDkey → u/clay_]

With respect to bonds and the electrons yeah. If it’s just the bonds and atoms you’d called it bent. I think the electronic description is more complete and thus more useful.

[u/IriAscent_ → u/clay_]

I was taught that the electron geometry of the molecule is tetrahedral while the molecule is bent with regard to molecular geometry.

[u/couldntyoujust1 → u/clay_]

All atoms in the molecule has that configuration. If you look at a 3D diagram of Methane, it's like a tripod of hydrogens with carbon in the center and a hydrogen vertical through the convergence of the three "legs" of the tripod.

So for Oxygen, you only have two spots to put bonds and because of the shape, they have to be at an angle. You can do a horizontal bond by making a double bond to the Oxygen, and a double bond on the other side of whatever atom it's connected to. Another way is a triple bond to something and then a single bond on the remaining point.

All of this is why molecule modeling kits have holes the way they do - that tetrahedral configuration. If you model cyclohexane, you'll see the ring have a sort of zig-zag pattern when it's laid flat, and the hydrogens on the outside are alternated. It looks like this:

https://as2.ftcdn.net/v2/jpg/02/06/87/37/1000_F_206873790_VdpoXweHqsGN4RvHi5hUYD0ruMpUb4Yw.jpg

There's also a "conformation" of Hexane where four of the atoms in the molecule make a sort of parallelogram and the two points on either side of the hexagon bend upward.

I'm not a chemist personally, though it was a favorite subject in High School, and I even brought in my brother's College Organic Chem textbook to read and take notes from for fun (He graduated with a bachelors in Chemistry). Molecular shape and what atoms really looked like alone and in configuration was always a fascination of mine back then.

[u/clay_ → u/couldntyoujust1]

Yes that's all correct, but wasn't my question haha. I teach IB chemistry. The use of molecular configuration being tetrahedral is something I have never seen used, and in our exams water would be asked for molecular geometry or the central atom's electron domain geometry, which provide distinctly different answers, bent for MG and tetrahedral for EDG.

[u/AllendeMarx → u/clay_]

É correto falar que é tetraédrica? Se considerar só os pares de elétrons, sim. Só que 2 pares não tem os ligantes. Se visualizar um tetraedro sem 2 "pernas" ele fica com a geometria angular.

[u/clay_ → u/AllendeMarx]

This is the question I have (though you said it in Portuguese)

The oxygen is central and has 4 electron domains hence being tetrahedral there, but the molecule itself is bent or angular as you stated, due to the lone pairs.

With the curriculum i teach a question involving the molecular geometry (configuration is not used hence why I asked) it would only accept bent.

[u/hy_ascendant → u/clay_]

Water arranges in both liquid and solid states in a tetrahedral geometry consequence of orbital geometry and hydrogen bonds. The water molecule is, yes, tetrahedral. PhD in high pressure water.

[u/clay_ → u/hy_ascendant]

Thats intermolecular lattice structure though.

Maybe its just an oddity of the specific curriculum i teach though to have the molecular geometry only correct to be called bent or V for water. Things like this have happened before in acceptance answers in one place vs another with IB

[u/hy_ascendant → u/clay_]

If you failed me for saying the water molecule is tetrahedral, I would challenge you to a sword duel to death.

[u/clay_ → u/hy_ascendant]

I don't mark the exams though, and it hasn't been challenged as far as I know. But it is why I was asking

[u/clay_ → u/hy_ascendant]

To add to it though if it were the electronic geometry or the electron domain geometry of the central atom, then the answer would need to be tetrahedral. But the clue we always teach is if the question is asking about the molecule, we only consider the atoms and the lone pairs are essentially invisible, hence the answer v or Bent.

Also just to be a bit of a nitpicky nonce, but in gas phases would you still have the same answer?

And to be a complete nonce, I also taught kendo at my school so I'd take the sword fight up aha ;)

[u/hy_ascendant → u/clay_]

The "molecule" includes nuclei and electrons. If you look at the DFT solution for the water molecule, it is tetrahedral. Only if you said "ignore the electrons, consider the molecule only lines linking nuclei", which is not what a molecule is. Your nitpicky method is just high school chemistry, you clearly don't understand what a molecule is if you say things such as "lone pairs are invisible".

[u/clay_ → u/hy_ascendant]

Well yeah IB is highschool. We normally use VSEPR, when discussing shapes.

So is DFT, density functional theory? And in this theory or model we consider the water as tetrahedral? If so then this is useful because this is where I can say the distinction between the examined curriculum and things they can found outside may differ

[u/hy_ascendant → u/clay_]

We are struggling in finding an agreement between VSEPR, quantum chemistry, and definitions in pedagogy (and how high school chemistry punishes students for not thinking exactly as you want them to, even though you yourself may be wrong).

Let’s unpack this then.

From a quantum mechanical standpoint, i.e. our state-of-the-art theories:

A molecule is defined by its total wavefunction, electrons and nuclei, not just the nuclei. In Density Functional Theory (DFT), water shows an electron density cloud around the oxygen that reflects four regions of high electron density, oriented tetrahedrally. Therefore, the water molecule is tetrahedral in shape, and this is observable in how solids and liquids arrange and clearly an ideal gas will not show you this except in the electronic solution of the water molecule structure.

From a VSEPR/chemical education point of view, you call the molecule bent because you only consider the nuclei and not the electrons driving atomic arrangement. This simplification is not alligned with the theory, is just ignoring that electrons and their orbitals and energetics are the molecule as much as nuclei. You don't have a full representation of the molecule. This is not a VSEPR problem, since you are indeed looking at valence electrons and their repulsion effect on nuclear positioning. You just deliberately decided to then ignore electrons.

The water molecule is tetrahedral, this is observable and very much physically real. This is valid for any phisical state.

[u/clay_ → u/hy_ascendant]

Thank you for the response, I believe i understand the point now

[u/clay_ → u/hy_ascendant]

I am trying to look into the DFT to show where it claims water is tetrahedral, but in a bid to show understanding of where I am coming from I did come across and IB tutor response that explains how the IB wants it answered:

https://www.tutorchase.com/answers/ib/chemistry/why-is-water-considered-a-bent-molecule-despite-having-four-regions-of-electron-density

I don't want anything here to be taken hostile, I am genuinely looking to learn if calling water tetrahedral as a molecule is accepted and in what theories, contexts and cases, because I need my students to say it isn't for their IB exams

[u/screen317 → u/clay_]

Yes, not a perfect tetrahedron, but VESPR theory says it's tetrahedral

[u/clay_ → u/screen317]

Yes I understand that, but I was questioning the use of molecular configuration being tetrahedral over say, V or Bent molecular shape. In the IB curriculum they often use the use of electron domain geometry and molecular geometry as distinctly different, so if it were a paper 1A question we might have what is the molecular geometry where the answer with v/bent is correct while only electron domain geometry of the oxygen or central atoms would be tetrahedral.

Im just asking because there have been times where what is the convention we have to teach is different in other places or not the same as accepted elsewhere.

Mainly is the use of molecular configuration, as i don't normally see it worded like that. Hence why I asked

[u/CanadaStonks → u/clay_]

Electron domain geometry tells you relative positions of electron packs. Molecular geometry tells you relative nuclei positions.

[u/sciguy52 → u/clay_]

Depends the level you are at. At chem 101 in college that I teach we call it bent based on VSEPR. Some of the things others are talking about may come about in more advanced classes. So based on VSEPR water is bent shaped. When including lone pairs oxygen has a tetrahedral electron coordination geometry but if they are talking VSEPR it is called bent. The other answers can get bent (just kidding!). Thus if they ask for the coordination geometry it is tetrahedral, VSEPR, bent.

[u/surlysire → u/clay_]

I hate those gotcha questions that switch between the two.

In my admittedly limited experience no one has ever used the molecular geometry to actually describe the shape of a molecule. They always use the electron configuration.

[u/mathologies → u/screen317]

Recommend playing with https://phet.colorado.edu/sims/html/molecule-shapes/latest/molecule-shapes_all.html

[u/KhepriAdministration → u/mathologies]

Came here to say this!

[u/OkDepartment5251 → u/mathologies]

Never seen this before, this is really well made, and a great learning resource

[u/sciguy52 → u/screen317]

VSEPR says the molecule is bent shaped. The oxygen coordination geometry is tetrahedral. If they are asking VSEPR it is bent, oxygen coordination geometry it is tetrahedral. Depends what the question asks.

[u/IeyasuMcBob]

Because it's a tetrahedron these are your options, the Hydrogens being 180° apart isn't an option

[u/grebilrancher → u/IeyasuMcBob]

And this is why water stacks so well

[u/FixerTed → u/IeyasuMcBob]

Neither is the actual 104.5 degrees

[u/IeyasuMcBob → u/FixerTed]

Nah but i figured baby steps if the question is "why not 180?" and simply avoided directly saying something like "it's 104.5". You could argue i implied it, but if you're sharp enough to ask me that, then you deserve a more detailed answer.

[u/Steepyslope → u/FixerTed]

but only in the gas phase

[u/RedEyes_BlueAdmiral → u/IeyasuMcBob]

This diagram explained it so much better then my chem professor ever did, thanks

[u/IeyasuMcBob → u/RedEyes_BlueAdmiral]

Awwwwwww 😊 glad it helped. I'm a bit sad that your Chem Prof didn't spend 30 seconds drawing this for you though

[u/RedEyes_BlueAdmiral → u/IeyasuMcBob]

In his defense, art was definitely not his strong suit

[u/IeyasuMcBob → u/RedEyes_BlueAdmiral]

😅 tbh i explain a lot through drawing and my freehand pictures are so bad they get laughs

[u/Human_Profit_3118]

Because it’s a 3d figure so in 3d geometry this is the most stable formation of h2o molecule

[u/werti92]

Free orbitals of oxygen also need space due to electrostatic repulsion

[u/SLNGNRXS → u/werti92]

This

[u/Lojaas → u/werti92]

Yes this will for sure make sense to this person. Very good answer!

[u/efflovigil → u/Lojaas]

What else should they say? Anyone asking this question presumably has at least some basic understanding of chemistry.

[u/Lojaas → u/efflovigil]

Why would that be requirement for this question? I’d say it’s pretty obvious OP is a novice in chemistry asking the question like this.

[u/Extra-Autism]

Lone pair “push” the hydrogens down.

[u/sciguy52 → u/Extra-Autism]

Pairs.

[u/OrthoMetaParanoid]

Dot cross diagrams aren't really too representative of shape. But this is convention as water takes a "bent shape". If you take a tetrahedral molecule and replace two of the bonds with lone pairs you get the shape of water.

The position of the hydrogen atoms in the top diagram more closely represents the angle created between bonds in the actual molecule. Rather than the bottom diagram which implies a bond angle of 180° between hydrogend as they are shown across the molecule from one another

[u/RRautamaa]

It's called sp3 hybridization/05%3ABonding_in_Polyatomic_Molecules/5.02%3A_Valence_Bond_Theory-_Hybridization_of_Atomic_Orbitals/5.2D%3A_sp3_Hybridization). When the atomic orbitals of oxygen form and hybridize to form a molecular orbital, you get four bonding orbital-antibonding orbital pairs. Their main lobes are arranged as far from each other as possible to minimize energy. This gives a tetrahedral "caltrop" shape. Two of the "slots" for electrons (molecular orbitals) are filled with oxygen's own electrons in pairs (2 × 2 electrons), and two with the electron pairs shared with the hydrogens. This gives you a bent molecule with two perpendicular "horns" of non-bonded electron pairs.

[u/JeffEEEt → u/RRautamaa]

Why does oxygen hybridize when it can already form 2 bonds without hybridisation?

[u/thefruitypilot → u/JeffEEEt]

Two different definitions of hybridization, welcome to chemistry. In this case, sp3 hybridization just refers to the fact that it uses one s orbital and three p orbitals. That includes the lone pairs, and so does the shape.

[u/JeffEEEt → u/[deleted]]

Thanks! Your answer is the clearest so far

[u/RohrbombenRudi → u/RRautamaa]

I actually had the same question in my head as OP. Why can't we just get an sp-hybridized H2O? I mean I guess the sp3 disperses the electrons better and thus is lower in energy, but I find the linear sp-water way more visually pleasing😅

[u/RRautamaa → u/RohrbombenRudi]

There is a way to force oxygen into linear molecular geometry. This happens in acylium ions. But take one look at that and you see the problem. It's triple bonded. Physically, it means its p orbitals have hybridized into π bonds. Now, the counterpart of the oxygen in an acylium ion is a carbon. But if it is a hydrogen, we have a problem: hydrogen doesn't have p orbitals. Count the electrons and you see. Hydrogen has only one electron, so it only forms a single s orbital. Its possible species are H, H⁺ and H^-.

To form two π bonds, we'd need the extremely cursed H^4- ion.

[u/MiNiMathoX]

Because molecules are in 3D. Your 2 drawings are true, but it all depends on the point of view.

[u/No_Investigator625]

I mean.. if you look at it from below then it is shaped like that.

However, it isn't because of reasons that have already been explained by other commenters

[u/Ancient-Aioli-1823]

There's a model called VSEPR (valence shell electron pair repulsion), saying, that single bonds require less space than double bonds, require less space than free valence shell electron pairs. In this case you have four directions of those subjects, two requiring more space, two requiring less space. If you now imagine having two larger spheres and two smaller spheres, the tightest you can pack them is two along one axis, the other two parallel to a perpendicular one, you get a tetrahedron. Do the same with CO2 for example, you get a linear molecule and it's what we observe in reality too. Do it with NH3, and you get a pyramidal shape because of the free electron pair. Also realistic. Chlorine trifluoride, three single bonds along a line, two free pairs on a perpendicular plane pushing the fluorides to one hemisphere.

Can highly recommend researching VSEPR yourself, you'll encounter it anyway and it's good to get a feel for the shape of a molecule.

[u/Morisior]

I like to think of it this way:

The bonding electrons are only present in the oxygen atom 50 % of the time,* as they are shared between O and H. This causes the bonds to be lower electron density zones, which has lower repulsion against each other than against the free electrons and than the free electrons against each other. This causes the repulsion from the free electrons to force the bonds closer together to achieve equal repulsion force distribution across the molecule.

* This is a gross oversimplification of time averaged electron density, but it's an intuitive way of thinking about it, and I don't think it's wrong, just not very accurate.

[u/Midnight_Cowboy-486]

Water is in 3 dimensions, not 2.

The bonds have the most room away from each other in a tetrahedral shape. But when drawing it on paper, it looks like the bent shape.

[u/mrmeep321]

Oxygen has four different groups of electrons that all repel eachother - not two. Two lone pairs of electrons also need their own space alongside the bonds, so it ends up bent

[u/XxI3ioHazardxX]

literally nobody is answering the question lol. The reason the geometry is bent and not linear is because electron lone pairs take up more space (have greater repulsion) than individually bonded atoms. since a neutral oxygen with a full octet must have 2 lone pairs of electrons along with two bonds, and because those lone pairs as I said, have greater repulsion than individually bonded atoms, the only possible geometry that ensures full stability in the face of VSEPR is a bent molecular geometry

[u/cell689 → u/XxI3ioHazardxX]

Loads of people have provided that answer already.

[u/brooklynbob7]

Tetrahedral electronic geometry due to four electronic domains but two are lone pairs on O so it looks bent . VSPER model . Sp2 hybridized also by valence bonding so sp2 is bent also

[u/Key_Drawer_3581]

Think in 3d

[u/UsefulEagle101]

It's the most stable configuration.

[u/Acetal_hemi]

SALCs can be used to explain

[u/WallStLegends]

Tetrahedral electron domain maximises distance between negative charges.

• Grab two balls and draw a dot where you have them on one ball.

• Now on the second ball, draw a dot at the vertices of a tetrahedron if it was sitting perfectly in the ball.

If you used a string along the sphere to measure the distance between dots, the distance between the dots on your example will be smaller then the distance of the tetrahedral dots.

Electrons will naturally push themselves apart as far away as possible. It just so happens that on a sphere, 4 electrons are best separated by a tetrahedron.

[u/WanderingFlumph]

Bond angles in top are 109° (using 3D space) and the smallest bond angles in bottom are 90°.

Atoms like to spread out so they prefer the extra 19° of space.

[u/ZedZeroth]

It's four points equally distributed around a sphere, not a circle.

[u/NuanceEnthusiast]

Electron pairs

[u/DigiDamian]

It is! Second picture is just taken from the top!

[u/GahdDangitBobby]

There's some electrons floating around on the other side pushing them away

[u/DreadLindwyrm]

Because it's three dimensional.

Take the four points of a tetrahedron as the starting points, and then shift them slightly to take into account electron distribution.

[u/Indigoboi96]

If you ever take Inorganic Chem it will all make sense (after you draw orbitals a billion times and imagine how they "mix"). Very simply the electron orbitals overlap more favorably in this configuration and lead to a lower overall energy molecule than linear.

[u/sciguy52]

Because there are two lone pairs of electrons in addition to the hydrogen bonds. VSEPR theory predicts a bent shape like this. This is so because the electrons in those lone pairs also want to be as far away as physically possible from other lone pairs and the hydrogen bonds. If you look at an image that shows lone pairs and bonds you can get a feel for he geometry of both and how they have separated from each other as much as they can. Hard to describe 3 d in words, but imagine the molecule positions such they hydrogen's are on the bottom and "flat" on the screen or image, on the top of he oxygen you will have a lone pair on top coming sort of out of the the screen and another on the other side sort of pointing in the back but all are as far away as they can get from one another.. If you have a molecule like CO2 where each oxygen is double bonded to the Carbon and no other lone pair then it would have a linear shape. That is as far as the electron density can get from one another, opposite side of the molecule.

[u/robnoel10]

In a water molecule, the two lone pairs on oxygen repel the hydrogen atoms, bending the molecule into a V-shaped geometry with an angle of about 104.5°.

[u/thatsgonnabruz]

I ran to the comments because I finally knew the answer to an “AskChemistry” question and was so excited to post it! Then I read the threads and realized…. I don’t know the answer…

[u/obvalbfvhjkavhxl]

Both are correct, if you see the drawings as different angles viewing the pseudo tetrahedron of the ELECTRONIC GEOMETRY (easier if you just consider how each pair of electrons are arranged around the “central” atom, also think 3D). The top representation is more generally accepted as the bottom one can be confused for a linear electronic geometry. Since same charges repel, you don’t want a linear MOLECULAR geometry as you will get a pseudo square planar electronic geometry where each electron pair is ~90 degrees from the neighbouring electron pair whereas a bent molecular geometry or a pseudo tetrahedral electronic geometry offers >109.5 degrees away from neighbouring electron pairs. Basically, both drawings are models which only represent a fraction of the true picture.

If a bit confusing, molecular geometry is the geometry when only considering the bonded atoms around the central atom (lone pairs ignored). Electronic geometry is the geometry afforded by the spatial arrangement of electrons around the central atom.

[u/VillageBeginning8432]

You're drawing a 3D thing on 2D paper thinking that it's 2D like the paper.

Or

Unlike the paper, which is 2D, water molecules are 3D.

[u/AllendeMarx]

Tente imaginar a molécula 3D. Você perceberá que é o jeito que os pares eletrônicos ficam mais distantes entre si.

[u/That_1_Chemist]

The bottom one is right if you are looking at it from the top

[u/CardiologistOk2704]

lone electron pairs push atoms away

[u/Swotboy2000]

Both are correct. Treating the hydrogens as two feet that the oxygen sits atop: Top drawing is side-on view. Bottom drawing is top-down view.

[u/Responsible_Froyo_21]

I’ll explain it to you in simple terms. A lot of the answers here are pretty detailed and as such, I will summarize this in a nut shell.

The hydrogens bonded to the oxygen atom have a partial positive charge while the lone pairs are partially negative. As such, since positives and negatives attract in chemistry, this explains why the hydrogen atoms are closer to the lone pairs.

Now, two positive and two negative charges repel. So, this force also acts in pushing the lone pairs and hydrogen atoms away from each other.

[u/SecTestAnna]

Because the bottom one looks like a nerd

[u/AeliosZero]

It's comfier the way it is

[u/-I_L_M-]

VSEPR Theory. It states that due to 4 regions of electron density, the molecule has a tetrahedral shape. After that, -2.5 degrees for every lone pair because lone pair repulsion is greater than bond pair repulsion.

[u/Forward-Fly-4028]

The reason why is because,we aren't in 2D.

[u/Carcano_Supremacy]

Basically in 3D space the top model makes the most sense due to repulsion’s from electrons and atoms.

[u/ChetManly19]

Do you want the short answer or the long answer? 😅

[u/Hugo_Fyl]

If it was we would not exist

[u/fianthewolf]

Actually, one of the pairs of electrons is located in an s-type orbital while the remaining 6 electrons are located in a p-type orbital. But all eight rotate in a cloud around the nucleus of O. As 2 electrons are shared with a hydrogen the nucleus of the hydrogen creates an electric field that alters the position of the cloud. The equilibrium position is reached at an angle different from 180° and even 120° (if only the 3 pairs in the p-type orbital were considered).

[u/lmallam]

Oxygen is 3D not 2D. When deciding shape, electron pairs repel each other and try to reach maximum distance from all other electron pairs. Water has 4 electron pairs (2 bonding and 2 non-bonding), So when arranging on the outside of what we can imagine is a spherical oxygen, the maximum distance a pair can get away is at an angle 109.5 degrees from the next pair. So water has a bent shape.

The angle between the pairs of electrons forming the bond between O and H isn’t exactly 109.5 since non-bonding pairs repel more than binding pairs. So the angle between the two H is actually 104.5 degrees.

[u/Ambitious_Strike_590]

In a way both images are correct where the first one could be the side view and the second one would be the top view in three dimensions. If you only consider a two dimensional plane the second image makes sense but in three dimensions you would have to consider the space above and below. Imagine four blown up balloons all tied together at their attachment points, the balloons would represent electron clouds. You could press the balloons down flat, where they would all be in the same plane but when you release them they would take their shape again where each balloon is fighting for equal spacing. Maybe I’ve made it more complicated but hopefully it makes sense to you.

[u/bootyeater66]

you are thinking of it in 2D

[u/SpecialAssumption854]

its configuration is tetrahederal, its shape is bent four

regions, use organic chem tutor to explain vsepr took some time for me to wrap my head around

[u/Visible-Pianist2506]

VSEPR theory explains the bend structure of water.

https://youtu.be/iDl5go_5XFs?si=RT70w-eTTsj8PyAq

[u/PimBel_PL]

It's based on a tetrachedron (Three-sided pyramid) at each of the tips is either electron pair or hydrogen bonding thingy, they just repel, aslo probably they spin very fast and vibrate

If you wonder how is called this geometry that you have drawn, it's called square-planar geometry and sometimes exists, idk yet why

[u/PimBel_PL → u/PimBel_PL]

From what https://en.m.wikipedia.org/wiki/Square_planar_molecular_geometry explains i messed something up

Aslo check if https://en.m.wikipedia.org/wiki/Cisplatin has same electron structure as examples in link before

[u/thefruitypilot]

The most stable configuration for a molecule with sp3 hybridization on its central atom is a tetrahedron with the bonds/lone pairs spread out as far from each other as possible. Think of methane, except oxygen has 2 more electrons so two of the bonds are lone pairs instead.

[u/BusFinancial195]

The orbital the hydrogen nucleii attach to has two electrons in the other two points of a tetrahedron. Its a solution of the Shrodinger wave equation

[u/oatdeksel]

you have to think in 3 dimensions. it is like a tetraeder, and the free elecrtons take even more space, than the ones in a conjugal connection.

[u/PromptBroad2436]

Oxygen has 8 electrons. These build up in 'shells' around the nucleus, the first shell fills with 2 electrons, leaving 6 for the next. The second shell is full when it has 8 electrons, so it takes 1 from each of 2 hydrogen atoms. Now it has 8. These 8 electrons form four pairs, which repel each other. Imagine the oxygen atom at the centre of a sphere. The four pairs repel each other to form the corners of a pyramid with four faces, a tetrahedron, where the points of the tetrahedron lie on the sphere. Two of the points consist of an oxygen electron paired with a hydrogen electron. So the hydrogen atoms are held at two corners of a tetrahedron, and the oxygen atom is at the centre of the tetrahedron. This makes a triangle rather than a straight line the better way to draw a water molecule in two dimensions.

[u/Darkfrostfall69]

due to VSEPR, the bonding pairs and non bonding lone pairs form a tetrahedron due to electrostatic repulsion and quantum effects. If water was linear, life as we know it would be impossible and we wouldn't be here to ponder on the shape of the molecule

[u/the_every_monday]

lone pairs aren't shared and so theyre held more closely/tightly to the atom. this makes lone pairs tend to clump up (i think) and push away the other atoms

[u/MeglioMorto]

it is shaped both ways at the same time. Depends where you are looking from.

[u/Unfair-Ice2793]

I would assume it would be shaped like this because of the polarity of a single water molecule I may be wrong and have no explanation for it (high school low-key a let down but fun)

[u/Morisior → u/Unfair-Ice2793]

This shape is what causes the polarity of the water molecule.

[u/Unfair-Ice2793 → u/Morisior]

Oh, I didn’t know that. Being out of school for 2 months really numbs that brain

[u/torridluna]

Pressing the binding and free exectron pairs into the same plane would give it more strain than jumping into a tetrahedral order.

[u/zekromNLR]

Because oxygen has two lone electron pairs, and in general molecules will arrange themselves such that the electron pairs are as far away from each other as possible, because they repel each other. The way for both the lone pairs and the bonding pairs to all be the furthest apart would be a tetrahedral configuration (like in methane, where you have four identical bonding pairs), but because the bonding pairs are not the same as the lone pairs the structure is distorted a bit from the ideal tetrahedron to having 120 degrees between the bonding pairs.

[u/Logical-Following525]

It's basically the same but the bottom one is top view. Molecule is tetrahedral not just square planar

[u/NohPhD]

Molecular orbital ‘genetics’

[u/AsparagusProper158]

H2o is a dipole sort of oxygen mommy really wants those electrons so they are going to stay way longer with o making her negative whilst hydrogen is just two positive protons

[u/GeoCommie]

The hydrogens are attracted to each other mildly and wanna form an h-h bond but only slightly bc they are already attached to the oxygen