SiH4, also known as silane, has a tetrahedral shape. This means that the silicon atom is at the center, with four hydrogen atoms arranged around it in a three-dimensional structure. The bond angles between the hydrogen atoms are approximately 109.5 degrees, which is characteristic of a tetrahedral geometry.
The tetrahedral shape arises because silicon forms four single bonds with hydrogen atoms, and these bonds repel each other equally, pushing the hydrogen atoms as far apart as possible. This results in the most stable arrangement for the molecule.
In summary, SiH4 has a tetrahedral shape due to the equal repulsion between the four hydrogen atoms bonded to the central silicon atom.