Iowa Code § 450.47: Life and term estates in personal property.

If an estate or interest for life or term of years in personal property is given to one or more persons other than those exempt by this chapter and the remainder or deferred estate to others, the property devised or conveyed shall be valued under section 450.37 as provided in ordinary estates and the value of the estates or interests devised or conveyed shall be determined as provided in section 450.51. The tax upon the estates or interests liable for the tax shall be paid to the department of revenue from the property valued or by the persons entitled to the estate or interest on or before the last day of the ninth month after the death of the testator, grantor, or donor. However, payment of the tax upon a deferred estate or remainder interest may be deferred until the determination of the prior estate as provided in section 450.48.