What are the fundamental conditions for a valid sale (Bay’) in Islamic law?

For a business transaction to be valid, several conditions must be met: 1. Mutual Consent: Both the buyer and seller must agree to the transaction without coercion. 2. Clear Proposal and Acceptance (Ijab and Qabul): The deal must be finalized in one sitting with words that indicate a firm sale. 3. Specificity of the Item: The item being sold must be clearly defined, known, and exist at the time of sale. It cannot be something vague or non-existent (like 'the fruit that will grow on this tree'). 4. Fixed Price: The price must be agreed upon and fixed; it cannot be left ambiguous. 5. Possession: The seller must own the item or have the legal right to sell it. If these conditions are not met, the sale is considered 'Fasid' (voidable/corrupt) or 'Batil' (invalid).