---
title: "Bohrium (Bh) — element 107"
description: "Bohrium is element 107, symbol Bh, most stable isotope 270. Configuration, properties, uses and neighbours."
url: https://atoneplace.net/element/bohrium/
site: "At One Place"
---

# Bohrium (Bh)

**Bohrium — element 107: Bh**

[270] · Transition metal · period 7, group 7

In 2000 a team produced six atoms of bohrium-267, one at a time, and passed each through a column of quartz to see what it would stick to — the atoms formed a volatile oxychloride and travelled exactly as technetium and rhenium do, confirming bohrium as a group 7 element. That is what chemistry looks like at this end of the table: six atoms, a chromatography column, and a decay signature to prove which atom went where. GSI originally proposed nielsbohrium, since IUPAC then discouraged using surnames alone.

## Properties

- **Atomic number:** 107
- **Symbol:** Bh
- **Mass number of most stable isotope:** [270]
- **Category:** Transition metal
- **Group:** 7
- **Period:** 7
- **Block:** d-block
- **Electron configuration:** [Rn] 7s² 5f¹⁴ 6d⁵
- **Electrons per shell:** 2, 8, 18, 32, 32, 13, 2
- **Oxidation states:** +7, +5, +4, +3
- **Discovered:** 1981 by Peter Armbruster, Gottfried Münzenberg and colleagues at GSI Darmstadt

## Electron configuration

- **Full:** 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d⁵
- **Noble gas shorthand:** [Rn] 7s² 5f¹⁴ 6d⁵
- **Shells:** K: 2 · L: 8 · M: 18 · N: 32 · O: 32 · P: 13 · Q: 2

## What it is used for

- Research only; no application outside the laboratory

## Hazards

- Intensely radioactive; exists only as individual atoms in an accelerator

> Melting point, boiling point, density and electronegativity are omitted: no measurement is possible. The mass given is the mass number of bohrium-270, the longest-lived at roughly a minute.

> Several physical properties are not listed for bohrium because no bulk sample has ever existed. Only a handful of atoms have been produced, often with half-lives measured in seconds, so published melting points and densities for elements in this range are calculations rather than measurements. They are omitted rather than presented as observed values.

## Neighbours in the table

| Z | Element | Symbol | Mass |
| --- | --- | --- | --- |
| 105 | Dubnium | Db | [268] |
| 106 | Seaborgium | Sg | [269] |
| 107 | Bohrium ← | Bh | [270] |
| 108 | Hassium | Hs | [269] |
| 109 | Meitnerium | Mt | [278] |

## Group 7

Elements in the same group share their outer electron count, which is why they behave similarly in reactions. Bohrium sits in group 7 with manganese, technetium, rhenium.

## Common questions

### What is the atomic number of bohrium?

107. That is the number of protons in its nucleus, which is what defines the element.

### What is the symbol for bohrium?

Bh.

### What is the electron configuration of bohrium?

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d⁵, or [Rn] 7s² 5f¹⁴ 6d⁵ in noble-gas shorthand.

## Related pages

- [Dubnium (Db)](https://atoneplace.net/element/dubnium/)
- [Seaborgium (Sg)](https://atoneplace.net/element/seaborgium/)
- [Hassium (Hs)](https://atoneplace.net/element/hassium/)
- [Meitnerium (Mt)](https://atoneplace.net/element/meitnerium/)
- [Manganese (Mn)](https://atoneplace.net/element/manganese/)
- [Technetium (Tc)](https://atoneplace.net/element/technetium/)
- [Rhenium (Re)](https://atoneplace.net/element/rhenium/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)