Revision:Thermal Stability of gp1 and 2 carbonates

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Revision:Thermal Stability of gp1 and 2 carbonates

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TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Chemistry > Thermal Stability of gp1 and 2 carbonates

Thermal Stability

Thermal Stability is the decomposition of a compound on heating. The higher the temperature needed to decompose something, the more thermally stable it is.

In group 1 and 2, the nitrates and carbonates get more stable down the group.

$\mathsf{Li_2CO_{3(s)} \longrightarrow Li_2O_{(s)} + CO_{2(g)}}$ The rest of group 1 follow the same pattern. (substitute Na, K etc where Li is).

$\mathsf{MgCO_{3(s)} \longrightarrow MgO_{(s)} + CO_{2(g)}}$ The rest of Group 2 follow the same pattern.

Only lithium carbonate and group 2 carbonates decompose (in Bunsen flame, 1300K). All other group 1 carbonates are stable in Bunsen flame. Both group 1 and group 2 nitrates decompose.

Group 1 nitrates except lithium decompose to form nitrites and oxygen gas. The group 1 cation except Li can form a stable lattice with the large nitrite ion, but group 2 cations are smaller due to higher charge density, and the lattice is unstable.