why BeCO3 is thermally unstable while BaCO3 is more stable?
Asked by bhuveshsharma1317 | 8th Jun, 2016, 07:36: PM
- The thermal stability of carbonates varies directly with the size of cation.
- The increasing order of thermal stability of carbonates is as follows:
- BeCO3 < MgCO3 < CaCO3 < SrCO3 < BaCO3
- BeCO3 is very unstable mainly because of the enhanced stability of BeO over BeCO3.
- Cations with high ionic potential have large power of polarisation. In crystalline solid, the M2+ cation is surrounded by oxygen of CO32- ions. When ionic potential of cation (such as small Be2+) a partial covalent bond is setup between M2+ and O, as a result C-O bond becomes weak due to withdrawl of electrons.
- Hence, carbonate of alkaline earths decompose into oxide and CO2. Large cations like Ba2+ have low ionic potential and are unable to polarise the electrons of O atom due to which carbonates of large cations are more stable.
Answered by Prachi Sawant | 9th Jun, 2016, 11:00: AM
- the cation which forms a yellow precipitate with potassium chomate in acetic acid is
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- Why the group 2 elements are called alkaline earth metals?
- Give the name of rarest alkaline earth metal found in igneous rocks.
- Which element of group 2 is not known as alkaline earth metal?
- Write down the electronic configuration of Ba.
- Why the second ionization enthalpies of alkaline earth metals are lower than alkali metals?
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- Why the Mg and Be reacts with air only in powdered state?
- Beryllium and magnesium do not give color to flame whereas other alkaline earth metals do so. Why?
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