History of Nihonium in Timeline

Nihonium (Nh), element 113, is a synthetic, extremely radioactive element. Its most stable isotope, nihonium-286, has a half-life of approximately 10 seconds. Located in the p-block of the periodic table, it belongs to period 7 and group 13, classifying it as a transactinide element. Due to its short half-life and synthetic nature, much of its chemical and physical properties remain unknown.

1908: Masataka Ogawa's Discovery of "Nipponium"

In 1908, Japanese chemist Masataka Ogawa discovered what he believed to be element 43 and named it "nipponium" after Japan. However, this claim was later disproven, leaving the name available for future use.

1979: IUPAC Naming Recommendations

In 1979, IUPAC recommended the name "ununtrium" (Uut) as a placeholder for element 113 until its discovery was confirmed and an official name was decided. While adopted in educational settings, scientists generally continued to refer to it as "element 113" or similar designations.

2003: JINR's claim for elements 115 and 113

In 2003, JINR claimed production of elements 115 and 113, which factored into their later contestation of IUPAC's decision to solely credit Riken with the discovery of element 113.

2003: Initial claims for element 113

Several isotopes of element 113 were claimed to have been discovered in 2003.

2003: Original Am + Ca Experiment

The original Am + Ca experiment was performed in 2003.

2004: JINR-LLNL Collaboration

In 2004, the JINR-LLNL collaboration conducted experiments related to the production of element 113 as a daughter of element 115.

June 2006: Claimed synthesis of a new isotope of element 113

In June 2006, a joint team from the Joint Institute for Nuclear Research (JINR) and Lawrence Livermore National Laboratory (LLNL) announced they had synthesized a new isotope of element 113 by bombarding neptunium-237 with calcium-48 nuclei.

2006: Further claims for element 113

Additional isotopes of element 113 were claimed to have been discovered in 2006.

2006: Investigation of the Am + Mg reaction

In 2006, researchers at the Heavy Ion Research Facility in Lanzhou, China, investigated the Am + Mg reaction, successfully producing four atoms of Bohrium (Bh). The decay chains of these atoms were analyzed, with some undergoing alpha decay to Dubnium (Db) and subsequent spontaneous fission, while others continued to Lawrencium (Lr) through further alpha decay.

2007: JINR-LLNL Collaboration

In 2007, the JINR-LLNL collaboration conducted further experiments related to element 113.

2009: Direct synthesis of Bohrium and study of its decay

In early 2009, the Riken team directly synthesized Bohrium (Bh) using the Cm + Na reaction. This was done to establish the link between Bh and element 113. They also observed that Db, a decay product of Bh, decayed through both spontaneous fission and alpha decay to Lr.

2009: Synthesis of element 117 and its decay to element 113

In late 2009, the JINR-LLNL collaboration, along with researchers from Oak Ridge National Laboratory (ORNL) and Vanderbilt University, synthesized two isotopes of element 117 through the Bk + Ca reaction. These isotopes decayed to element 115, and subsequently to element 113.

March 2010: Failed synthesis attempt of Roentgenium

In March 2010, the Riken team attempted to synthesize Roentgenium (Rg) directly using the Tl + Zn reaction, but this attempt was unsuccessful, and the approach was subsequently abandoned.

2010: Preliminary Chemical Experiments Begin

Between 2010 and 2012, preliminary chemical experiments at JINR explored the volatility of nihonium, but faced challenges in detection, suggesting either noble-gas-like behavior or low volatility.

2010: JINR-LLNL-ORNL-Vanderbilt Collaboration

In 2010, the JINR-LLNL-ORNL-Vanderbilt collaboration discovered elements 117 and 115, and observed the production of element 113 as a decay product.

2011: Joint Working Party (JWP) report on elements 113-116 and 118

In 2011, the JWP published its report on elements 113-116 and 118. They acknowledged the JINR-LLNL's discovery of elements 114 and 116 but didn't accept either team's claim for element 113, nor the JINR-LLNL claims for elements 115 and 118, citing insufficient evidence and theoretical limitations.

2011: Tōhoku earthquake and tsunami impact on research

The 2011 Tōhoku earthquake and tsunami led to increased electricity prices and subsequent shutdowns of accelerator programs to conserve costs. However, Morita's team at Riken was permitted to continue their experiment related to element 113.

August 2012: Confirmation of element 113 synthesis

In August 2012, the Riken team produced and identified another atom of element 113, following 450 more days of bismuth irradiation with zinc projectiles. This confirmed their earlier synthesis of the element.

2012: Challenges in Nihonium Volatility Studies

By 2012, initial attempts to study the volatility of nihonium posed technical difficulties, suggesting that it either behaved similar to noble gases or had lower-than-expected volatility. The potential for using hydroxide formation (NhOH) for easier transport was raised.

2012: Repetition of the Bk + Ca experiment at JINR

In 2012, the Bk + Ca experiment was repeated at JINR.

August 2013: Confirmation of 2003 Am + Ca experiment

Researchers at Lund University and GSI confirmed the findings of the 2003 Am + Ca experiment conducted by the JINR-LLNL collaboration, which aimed to synthesize element 115.

2014: Repetition of the Bk + Ca experiment at GSI

In 2014, the Bk + Ca experiment was repeated at GSI.

August 2015: Confirmation of Element 115 and its Daughters

In August 2015, the team at the Lawrence Berkeley National Laboratory (LBNL) published confirmation of the synthesis of element 115 and its decay products, including element 113.

December 2015: IUPAC assigns discovery credit of element 113 to Riken

In December 2015, IUPAC officially recognized Riken's discovery of element 113, while elements 115, 117, and 118 were credited to collaborations involving JINR. This marked the first time a team of Asian physicists named a new element.

January 2016: Official Publication of JWP Report and Recognition of Element 113 Discovery

In January 2016, the JWP officially published their report recognizing Riken's discovery of element 113. Despite inconsistencies in individual decay energies, the consistent sum of decay energies confirmed the identity of element 113. The JWP acknowledged the production of element 113 by the JINR-LLNL collaborations in 2004 and 2007 but didn't grant shared credit due to insufficient characterization of the produced nuclides.

February 2016: Name Selection Process Begins

Following official recognition of their discovery, the Riken team initiated discussions in February 2016 to select a name for element 113, aiming for a name that would honor its discovery in Japan.

March 2016: "Nihonium" Proposed

In March 2016, after deliberations that included considerations of names like "japonium," the Riken team formally proposed "nihonium" (Nh) to IUPAC, derived from "Nihon," a Japanese word for Japan. This proposal aimed to recognize the discovery in Japan, honor the public support for the research, and pay homage to chemist Masataka Ogawa's prior discovery of then "nipponium."

May 2016: Critique of JWP's element 113 discovery criteria

In May 2016, a study from Lund University and GSI criticized the JWP's rationale for recognizing element 113, specifically the "sum argument," due to the possibility of gamma decay or internal conversion influencing decay chain properties. However, they ultimately endorsed the IUPAC's approval of element 113 based on the congruence of Riken's data.

June 2016: Public Review and Controversy

The proposed name "nihonium" was publicized in June 2016 with a five-month period for public review. This followed criticism concerning the lack of transparency in the element naming process.

November 2016: Official Approval of Nihonium

In November 2016, IUPAC officially approved the name "nihonium" (Nh) for element 113, marking a historic milestone in chemistry and a point of national pride for Japan.

2016: Planned joint announcement by IUPAC and IUPAP

A joint announcement by IUPAC and IUPAP regarding element discovery was scheduled for 2016 but was preempted by IUPAC due to a leak to Japanese newspapers about Riken's credit for element 113.

March 2017: Naming Ceremony

The official naming ceremony for nihonium took place in Tokyo, Japan, in March 2017, attended by the Crown Prince Naruhito, solidifying the element's place in the periodic table.

June 2017: JINR's response to criticism

In June 2017, members of the JINR team published a rebuttal to the criticisms of their data on elements 113, 115, and 117, defending the IUPAC's approval of their discoveries.

2017: Further Chemical Studies and Unexpected Surface Interaction

A 2017 experiment at JINR modified the setup to address previous challenges, but no nihonium atoms were observed after separation. This indicated an unexpected high retention of nihonium on PTFE surfaces, contradicting theoretical predictions. The need for high-temperature techniques and alternative carrier gases like bromine were proposed for future investigations.

2024: Adsorption Studies and Reactivity of Nihonium

In 2024, a GSI experiment studied the adsorption of nihonium on SiO2 and gold. Nihonium exhibited less reactivity with SiO2 than thallium, but more than copernicium and flerovium, attributed to the relativistic stabilization of the 7p1/2 shell.