Is it permissible to purchase a second mosque and donate it in Florence, Italy, given that the first mosque faces administrative and methodological problems and its location is unsuitable, and what is the ruling on excommunicating whoever participated in purchasing the new mosque?

There is no harm in purchasing a place to be adopted as a new mosque if there is a need for it, such as the need to expand space for Muslims and protect them from places of corruption, or due to the lack of sufficient space for women or a school for children in the existing mosque, or if there is no intention to harm the first mosque.

Prohibition applies to building a mosque next to another mosque with the intention of causing harm, or without need. The correct view is that if there is no need, building a nearby mosque is prohibited, even if harm is not intended.