With an Atomic Mass of 164.9303, the chemical element Ho (Holmium) is one of the rarest compounds on earth. Holmium proves excellences in terms of malleability and ductility. This is a white-coloured, silvery textured soft material that possesses unusual magnetic characteristics. From nuclear control reaction procedures to medical treatment options that are non-invasive to a patient, Holmium plays a key role in many real-time applications. Known for its high significance, let us learn about this element Ho, by understanding its properties, chemical nature, examples, and a few important applications. 

Important Details about What Holmium is

‘Per Teodor Cleve’ (1840-1905) was the 1st Swedish chemist, who discovered Holmium spectroscopically in 1879 when working with another earth metal ‘Erbium’. The name was assigned for his place of birth named Uppsala in Stockholm, Sweden. 

Holmium is one of the rarest elements found on earth and is categorized as lanthanides. The element Ho is located in the 67th position in the periodic table. This is a silver, shiny material but turns yellowish oxide (Ho2O3), during the process of oxidation or when heated directly. Being completely soluble in acids, Holmium gets affected due to the presence of oxygen and water. 

As we noted before, the element Holmium has unusual magnetic potential and it also records the highest magnetic moment ever, which is 10.6 µB for a naturally-derived chemical substance. 

Let us now quickly understand the physical and chemical properties of Holmium from the following.

Physical and Chemical Properties of the Element Ho

Firstly, here are the physical properties of Holmium.

  • A key rarest element found on earth. But it is more common than silver and gold. 

  • Soft and silvery in texture and appearance. 

  • Is both malleable and ductile. 

  • Amount of Ho available inside the crust of the earth is approximated to be 0.7 to 1.2 parts per million. But mined in a few countries such as India, the United States of America, Sri Lanka, China, Australia and Brazil, in reserves estimated to be around 400,000 tonnes.

  • Hexagonal close-packed (hcp) is the crystal structure of Ho.

  • Forms an alloy when combined with other metals.

  • High temperature is proportional to its high reactivity.

  • HOL-me-um is the pronunciation. 

  • Holmium possesses unusual attractive properties along with electrical conductivity, and majorly seen at times of low-temperature conditions.  

  • Gadolinite and Monazite are the rarest isotopes of Ho.

Now, we have Some Important Chemical Properties.

  • [Xe] 4f11 6s2 is the Electronic Configuration of Ho.

  • The atomic number is 67 and the atomic mass is 164.9303.

  • Noted in the periodic table at Row 6.

  • Present in the section of Lanthanides in the f-block of the periodic table. 

  • Solid structure at 20°C celsius. 

  • Somewhat electropositive. 

  • Stability in room temperature. 

  • Trivalently bonded.

  • 1.23 is the Electronegativity as per the Pauling scale.

  • 2,720°C (4,930°F) is the Boiling Point and Melting Point is 1,470°C (2,680°F).

  • 8.803 grams is the Density of Ho per 1 Cubic Centimetre.

  • Good desolvation in other acids, similar to other metals.

A gist about the Isotopes and Extraction of Holmium

An isotope is defined to be the more than 2 forms of a chemical element. For the element Ho, there is only 1 naturally-existing isotope which is holmium-165. Holmium-163 is a synthetic isotope with a half-life of 4570 years. 

There is a minimum count of 20 isotopes of Holmium that are found to be radioactive. However, there is no proven cases or enough scientific evidence about the health issues or safety measures for using Holmium to date. 

When there is a chemical ration between Holmium Fluoride (HoF3) and the Calcium metal, then this process gives rise to Holmium (Ho). 

The Significant Applications of Holmium

Even though the element is radioactive and there is no proven record for its toxicity (generally stated to be Low) there are enough applications for using Ho in industries and other research fields. Given below are some important applications of Holmium in real-life. 

  • Holmium acts as a Flux concentrator to many high magnetic fields and also, this is used as an alloy in the production and manufacturing of magnets.

  • The rods of nuclear control reactors make use of Holmium considering its good neutron absorption capacity. Moreover, the same absorption power of Ho makes it suitable for use as a burnable poison. 

  • For Cubic Zirconia and Glass production, the Holmia also called the holmium oxide, is preferred for giving a natural yellow and red colouration. 

  • To calibrate things, optical spectrophotometers prefer Holmium.

  • The pole pieces of several static magnets make use of this powerful element Ho, owing to its high permeability. 

  • For non-invasive medical processes, the element Ho is used in the case of solid-state specialized lasers for programs such as cancer treatment, fibre-optics, dental operations, and even for kidney stones.

  • Holmium is majorly used in the treatment procedures of the eye disorder glaucoma, and even to correct failed or wrong glaucoma surgeries. Holmium lasers come handy for reducing the abnormal range of pressure in human eyes. 

  • In the future, with enough research for its quantum property, one can utilize Holmium for quantum computers and other classical control methods. 


Holmium (Ho) is a silver, rare earth metal, with the atomic number 67 and present in the 6th row, f-block of the periodic table. The element is categorized under the lanthanides. It has unusual electrical and magnetic properties and is used in nuclear reactors for its good absorption power. The reactivity of Ho is high at increased temperatures but usually stable at room temperature. Holmium-165 is the only naturally-occurring isotope but there are 20 radioactive isotopes noted for Ho. The toxicity of this element is still not known completely but there is a good number of applications for Holmium in the fields of medicine and dental procedures.

FAQ (Frequently Asked Questions)

1. Why is Holmium Considered to have Unusual Magnetic Properties?

Holmium is considered to have unusual magnetic properties because when the temperature is below 19 K, this element is ferromagnetic, but is known to be a paramagnet during ambient conditions.

2. Is there any way to Isolate the Metal of Holmium Using a Halogen Compound?

Yes. By reducing anhydrous fluoride  (F) or chloride (Cl) along with Calcium metal (Ca) one can isolate the metal of Holmium. 

3. Can Holmium be Used for Wiring Certain Objects?

Yes. Holmium has the property of extreme ductility, where Ho can be drawn into the required thickness and length of wire. Moreover, the element is also malleable and can be shaped and reshaped in its structure and formation. 

4. Give the Equations of Holmium Reacting with the 4 Halogen Present. 

Holmium reacts with Fluorine to form Holmium Fluoride [2 Ho (s) + 3 F2 (g) → 2 HoF3 (s)]. It reacts with Chlorine to produce Holmium Chloride [2 Ho (s) + 3 Cl2 (g) → 2 HoCl3 (s)]. The element Ho reacts with Bromine and gives our Holmium Bromide, equated as [2 Ho (s) + 3 Br2 (g) → 2 HoBr3 (s)]. Lastly, on reaction with Iodine, Holmium Iodide will be formed [2 Ho (s) + 3 I2 (g) → 2 HoI3 (s). Only Holmium Fluoride is Pink in colour while the other 3 Halides are yellowish. 

5. What is the Bulk, Shear and Young’s Modulus of Holmium?

The Bulk Modulus of Holmium is 40.2 GPa and 26.3 GPa is the Shear Modulus of Ho. the Young’s Modulus of Holmium is said to be 64.8 GPa respectively. 

6. Mention the Critical Surgical Procedures where Holmium Plays a Major Role.

Holmium plays a major role in a few critical surgical procedures such as ablation (HoLAP), breaking-up of kidney stones (lithotripsy), benign prostatic hyperplasia, prostate enucleation (HoLEP) and in resection (HoLRP).

7. What is the Actual Colour of Holmia, the Holmium Oxide?

The actual colour of Holmia, the Holmium Oxide is yellow during natural light conditions but appears pinkish in the case of fluorescent lighting.