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.
The rest of group 1 follow the same pattern. (substitute Na, K etc where Li is).
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.
- Li acts as a group 2 ion because it is also very small. Li and group 2 nitrates therefore decompose to oxides, nitrogen gas and oxygen gas.
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