Rutherfordium

Rutherfordium is a synthetic chemical element. Its official chemical symbol is Rf, and its atomic number is 104, which means that a rutherfordium atom has 104 protons in its nucleus. Rutherfordium was the first super-heavy element to be discovered. Super-heavy elements are located in period 7 – the bottom row of the periodic table of elements. The element is named after one of New Zealand’s most famous scientists – Lord Ernest Rutherford.

Synthetic elements explained

Synthetic elements do not occur naturally on Earth. There are 26 synthetic elements. There are also a few elements like astatine (At) that were first synthesised but later discovered as naturally occurring in trace amounts. In the case of astatine, there are about 25–28 g of it in the Earth’s crust – the same weight as a slice of bread! It’s easier to synthesise astatine rather than ‘find’ this unstable element.

Synthetic elements are produced in nuclear reactors, particle accelerators or atomic bombs. Rutherfordium is created by nuclear bombardment – smashing tiny bits of atoms into other atoms. This is fitting because Ernest Rutherford pioneered the research that first split an atom in 1917.

All of the synthetic elements are radioactive and unstable. They do not exist for long because of radioactive decay.

A controversial element

Element 104 has a controversial past, beginning with its discovery. In 1964, Russian scientists from a lab in Dubna were the first to synthesise the element. In 1969, American scientists used a different method to synthesise element 104 and discovered additional information about it. In 1973, an independent team confirmed the American synthesis.

The naming rights for a newly discovered element goes to the person or team who discovers it. The Russian team named element 104 kurchatovium (Ku) in honour of Igor Kurchatov, a famous Soviet nuclear physicist. The American team challenged the Russians’ discovery claim and named element 104 rutherfordium (Rf) in honour of Ernest Rutherford, often called the father of nuclear physics.

Disputes also arose over the names of elements 105 and 106. Scientists referred to this controversy as the Transfermium Wars because it involved the elements that followed fermium on the periodic table of elements.

The International Union of Pure and Applied Chemistry (IUPAC) is responsible for approving the names of elements. Until it could settle the dispute, it used the temporary name unnilquadium (Unq) – the Latin names for the numbers 1, 0 and 4. IUPAC eventually decided that the American and Dubna scientists should share the credit for the discovery. In 1997, IUPAC gave the name rutherfordium to element 104 and the name dubnium (Db) to element 105.

There is one naming convention that everyone has agreed on in recent times – all new elements end with the letters -ium.

A second naming controversy

A second controversy about names is probably only recognised by New Zealanders. Ernest Rutherford was born, raised and (mostly) educated in New Zealand, and we claim him as one of our greatest scientists. Rutherford’s amazing discoveries took place in labs in Canada and England so he is often referred to as either a Canadian scientist or British scientist – which New Zealanders strongly dispute!

An interesting (but not very useful) element

Ever since Dmitri Mendeleev first produced the periodic table of elements, scientists have been trying to fill in the gaps for proposed but undiscovered elements. The real value of an element like rutherfordium is in the knowledge it provides. Only a few atoms of this element have been synthesised. In its most stable form, rutherfordium only has a half-life of 1.3 hours, so it is difficult to study. The only thing we really know about it is that it is a solid at room temperature.