Paying a deposit to secure property

If A pays a cash deposit to B on the understanding that it is to secure a particular property what legal standing, if any, would this have if B now wishes to sell said property to someone else. A also refuses refund of the deposit.
Can A get an injunction to prevent B selling to anyone else albeit no contract has been signed??

If there are no signed contracts in place the deposit is fully refundable and B remains free to sell it a) to someone else b)for a higher price. A is entitled to refund of the deposit but cannot insist on enforcing the contract if they refuse to accept the refund.

Thanks Sheena for response. Do you know if this is also the case in the UK. I heard that in the UK it is standard practice to give a cash deposit and that it may have legal implications.

Thanx