Is it permissible to purchase gold, silver, gas, oil, or food commodities from forex platforms using only money, without leverage, based on the premise that electronic registration is considered a [valid] taking possession (taqabud), and what is the legitimate alternative for investing money if that is not permissible?

It is a condition for selling and buying gold with money that both exchanged items be seized in the contractual session, whether this seizure is actual or constructive. Constructive seizure is realized by designating the gold and enabling the buyer to dispose of it, or by seizing a certificate of ownership for a specific and distinct ingot. Therefore, it is not permissible to sell an undesignated ingot or without actual seizure. As for non-riba items like gas and oil, mutual seizure is not a condition for their sale.