Want to know how the stability of hydrides is? In fact, there are a few little secrets that can help you judge!
First, look at the size of the nuclear spacing, which is the bond length or the atomic radius of the non-hydrogen element. In general, the shorter the bond length or the smaller the atomic radius, the stronger the chemical bond and the higher the thermal stability. For example, HCL and Hi, HCl has a shorter bond length, so it is more stable.
Secondly, the strength of the non-metallic properties is also important. When hydrides have similar bond lengths or radii, the chemical bonds formed by non-metallic elements with hydrogen are more stable. For example, the N-H bond in NH4(+) is more stable than the C-H bond in CH4 because nitrogen attracts electrons more than carbon.
Let's take a look at the electronegativity difference. Hydrides formed by electronegative elements with hydrogen are more stable. For example, NH3 is more stable than CH4 because nitrogen is more electronegative than carbon.
There is also the size of the bond energy, the higher the bond energy, the less likely the substance is to break the bond, and the more stable it is. You can consult the chemical data sheet to see what the bond energy of the different hydrides is to determine their stability.
The thermal decomposition temperature is also a reference indicator. The higher the decomposition temperature, the less likely the hydride is to decompose and the higher the thermal stability. For example, the decomposition temperature of CH4 is higher than that of NH3, so CH4 is more stable.
Finally, the molecular structure cannot be ignored either. Carbon like CH4 is sp hybridized and forms a stable tetrahedral structure, while non-polar molecules are generally more stable. But the nitrogen in NH3 is also sp hybridized, but because there is a lone electron pair, the molecular structure is asymmetrical, it is a polar molecule, which may affect its stability.
Therefore, to judge the stability of hydrides, it is necessary to comprehensively consider many factors such as nuclear spacing, non-metallics, electronegativity, bond energy, thermal decomposition temperature, and molecular structure. In this way, you will be able to judge the thermal stability of hydride more accurately!