WASHINGTON (AP) – Revisiting one of physics’ most embarrassing cases of scientific misconduct, researchers from Russia and the United States announced Monday that they have created a new super-heavy element, atomic number 118.

Scientists said they smashed together calcium with the manmade element Californium to make an atom with 118 protons in its nucleus. The new element lasted for one millisecond, but it was the heaviest element ever made and the first manmade inert gas – the atomic family that includes helium, neon and radon.

If confirmed, the still-unnamed element would be placed beneath radon on the periodic table of elements, said Ken Moody of the Lawrence Livermore National Lab in California, which was joined on the project by Russia’s Joint Institute of Nuclear Research.

The findings were published in the journal Physical Review C. The same research team has created four other elements.

In 1999, scientists said they created element 118, only to withdraw their claims in 2002 amid charges of falsified data and the firing of a scientist. That group of researchers included three from the team that announced Monday’s discovery.

This time, Moody said, safeguards were adopted to minimize the possibility that just one scientist held critical data.

Yale University physics professor Richard Casten, an associate editor of the physics journal, said the latest work was subject to intense scrutiny “because of the sensitivity of the issue.”

Casten said such new elements are not discoveries until they are confirmed by other scientists. That may take several years, Moody said.

The element was created last year in Russia using a minuscule amount of Californium provided by the Americans. After a millisecond, it decayed into element 114, then into element 112 and then split in half, Moody said.

Creating a new element “is sort of the Holy Grail of nuclear physics,” said Konrad Gelbke, a scientist who was not on the team but directs the National Superconducting Cyclotron Laboratory at Michigan State University. “It’s extremely hard to do.”

Moody said the new element will not be named until it is approved by an international association of chemists. Elements 113, 114, 115, and 116 are still unnamed.

AP-ES-10-16-06 1804EDT