 Right on when this trihalytes reacts with water and forms boric acid, boric acid that is S3dO3 plus Hx. Next write down in solid AlCl3, in solid AlCl3 aluminum is octahedrally coordinated it means it has six coordination number and two chlorine atoms in each octahedra are shared between the two chlorine atoms in each octahedra are shared between AlCl3, this is crystalline AlCl3 solid liquid form and there is octahedra okay I will just explain what it is see AlCl3 actually in solid form it exists in the form of its dimer dimerization the expression okay so AlCl3 when dimerize it forms what Al2Cl6 right now the structure of this is we have aluminum one aluminum is coordinated we have an octahedra see octahedral geometry is something like this this is suppose any metal M and we have suppose this elements present this is octahedral geometry this octahedral is what square bi-terametric bi-terametric right so square is this and bi-terametric this octahedral geometry okay so Al2Cl6 exists like this aluminum we have here the center one chlorine here one chlorine here this chlorine atom actually it is bonded this is the dimer structure of this its rate is lone pair no AlCl3 this is two kind of banana bond banana bond B2S6 how it forms this here it is actually it is the electron pair it is related to this aluminum so this is a coordinate bond this is a coordinate bond now this coordinate bond will represent by simple bond okay actually like AlCl3 is electron deficient okay so AlCl3 is not that state so crystal form a biscuit dimerized and becomes a state octahedral this chlorine also attached with the another proton atom like this all these things are more attached like this it is a chain structure basically the dimer structure is this but this is a coordinate bond you can represent like this also but nowadays we don't represent this arrow but we represent the simple bond like this structure is because it's just a rule if you have third period element then one single bond is nothing but a coordinate bond if it is possible means by looking at the structure or bond you cannot say whether it is coordinate bond or simple covalent bond you should have this idea it is the whole nitrogen and H4 plus if you write okay and H4 plus we write like this this is the coordinate bond so for third period elements we represent simple bond like this but for second period elements we represent like this even if you write this simple bond it will have this is also right this is also not like in the new addition new book they have adopted this particular rule coordinate bond we can actually it is it forms by the donation of a pair of electron so it is the new definition of coordinate bond is what that the electron pair is not originated from the same atom so it gives one electron to the atom and then sharing takes place as a definition of coordinate bond so nowadays coordinate bond is nothing but the type of covalent bond so you just give it a like so this right now in right now in liquid form LPLPM okay what in liquid and vapor form in liquid and uh six vapor form in it is coordinated with 4th chlorine atom why we draw the blue chlorine guys because this is octahedral uh it's coordinate six coordination number right so aluminium must have coordination number is what it is the uh bond the metal forms with the elements or ligands is the better word we use right so this aluminium has has six coordination number it was six bond with this chlorine atoms 3 4 5 6 this is factual it is observed in crystalline form solid state okay that too in liquid and vapor form aluminium has 4 tetrahedral arrangements so we prefer satisfying its coordination number over its octahedral octahedral it's it's true only for second period element in the third period so d orbital and cancel expander okay octahedral actually it's so this exists in vapor and liquid form right tetrahedral coordinated octahedral coordinated see these are the structure uh based on the fact okay uh when they have done this uh the research on the structure of this like we have many different spectroscopy that various methods of determining that structure right so in liquid state uh in crystalline form this is the structure possible and in liquid and vapor form this is the structure possible so what they ask you the third real question and here it is octahedral coordinated means six bond is there with each chlorine each each aluminium and here it is tetrahedral coordinated that you have to memorize liquid and vapor and this is this slide solid okay next slide down hydrides of boron right on the elements of group 13 combines directly with halogen hydrogen and forms hydrides and forms hydrides of m h thing type b h 3 is the simplest hydride two series of hydride actually it forms two series of hydride it's formed the one is b n h n plus four this is one type of you know compound possible and another one is b n h n plus five okay so it is b 2 h 6 the dimer form here and here it is b b 4 h that b 6 h 11 one of the compound is this is not important di borane belongs to this series of hydrides okay b n h n plus okay b 4 h 10 is done oh this is not five this six this is the general form of the hydrides which is di borane b b 2 h 6 okay b s 3 is the simplest hydrides of boron which is again electron deficient and to get stability it dimerize and form b 2 s 6 okay so b 2 s 6 makes you write down di borane di borane it is prepared by the reduction of it is prepared by the reduction of b cl 3 with li al h 4 lithium aluminium hydride li al h 4 lithium aluminium hydride li al h 4 is a very strong reducing it organic okay so b cl 3 with li al h 4 in presence of one b cl 3 with li al h 4 in presence of ether reaction right on b cl 3 with b cl 3 plus li al h 4 in presence of ether it forms b 2 is 6 plus li cl plus al cl 3 with 6 plus 1 li cl plus al cl 3 we have b cl 3 b cl 3 with li al h 4 it forms b 2 h 6 plus li cl plus al cl 3 okay another method is what this card if you do the reaction with h 2 this electric discharge it forms b 2 h 6 plus f 3 the reaction with lithium hydride that is also a method of formation of b 2 h 6 b 3 plus li al 4 also this we use forms li b m 4 oh yeah 6 b m 8 so boron dry fluoride with lithium hydride gives you b 2 h 6 okay another properties of this to write down it is a colorless gas stable and low temperature low temperature see low we generally don't define around less than 100 we can say 60 80 even in low temperature we also vote even in low temperature we also vote in minus 70 minus 70 but not that low it is around 50 so I don't at high temperature at high temperature it converts into higher boron and on red heat and red heat higher boron means when we can add over series so second one is the higher boron reaction is not there but the second one is the higher boron high temperature it converts into higher boron and on red heat it forms pure boron and hydrogen that it means extremely high temperature it forms pure boron and hydrogen see b 2 is 6 is the timer of b h 3 correct timer of b h 3 so this b s 3 the molecule you see there are three bonds of boron and hydrogen we have and the another molecule is also this what happens boron has both of this boron has one vacant b orbital this pair of electron is donated to this boron and this pair of electron is donated to this boron so we'll get a bridge bond here structure is h b h b h so here in this bond there is there are only two electrons four electrons are not there however there are two bonds present so what we say this two electron is shared among the three nucleus two boron and one hydrogen same thing we have here right so we have three nucleus one two and three so it is pre-center and since two electrons are shared so it is pre-center two electron attracted towards the three nucleus it's just they are in a bonding state with these three nucleus okay that's why this kind of forms okay so this bond we call it as bridge bond and this is pre-center two electron bond what is the other name banana bond why it is banana bond because you can make right with the etch in here but it looks like banana that's why so many more minutes wait let me finish this let me finish this okay thank you i see so just two minutes we'll finish this two reactions here okay your reactions you write down the stress in reactions we have 3 2 s is the reaction with O2 it forms P2O3 with H2O with H2O it forms S3 B O3 and hydrogen gas also POH B O2 and H2O O2 so these reactions are there but these are not very important the important reaction here is again the heating effect of this P2H6 with NH3 we call it as H2O 2 NH3 like we have hydrogen compound this we call it as H2O okay now when you heat this at 200 yes this converts into you know this compound inorganic benzene borazole right borazine inorganic benzene okay the structure of this is what borazole inorganic benzene