How is the thermal stability of nitric acid related to its structure?

How is the thermal stability of nitric acid related to its planar structure?


In textbooks it is written that nitric acid is unstable at room temperature and decomposes where $\ce{H2SO4}$ and $\ce{H3PO4}$ are stable and decompose at much higher temperature.$\ce{H2SO4}$ and $\ce{H3PO4}$ have tetrahedral structures.


