Explanation:

- Take an interest:

- This is when a party gains a right or stake in a property, but it's not the primary purpose in equitable mortgages.

- Take a possession:

- This involves taking physical control of a property, which doesn't apply to equitable mortgages where possession remains with the property owner.

- Create a security:

- This is the correct intention. The deposit of title deeds in an equitable mortgage is to secure a loan or obligation without transferring ownership.

- Take a consideration:

- This refers to the exchange of something of value in a contract, which is not the primary purpose of depositing title deeds in this context.