REACH 2018
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Chemically-produced (synthetic) molybdenum disulfide

(Pre-) SIEF information and actions for pre-registrants

Please read this page carefully, and then take appropriate action as described in the section at the foot of this page: ‘What do I do next as a pre-registrant?’.

Substance Identity for chemically-produced molybdenum disulfide:

The substance to be REACH-registered is molybdenum disulfide (MoS2) that is chemically-produced during the activation or so called pre-sulfiding of refining & petrochemical catalysts, when molybdenum oxide (MoO3) is transformed by reaction with a sulphur compound (2R2S or RSSR or H2S) into its sulfidic form (MoS2).   It is not a substance produced in isolation, but as a component of a catalytic mixture. Intending REACH co-registrants are welcome to E-mail MoCon for a copy of the Substance Identity Report.

Identified Uses:

Please view the list and check that your use has been included.  If it is not yet included, please use this E-mail form to provide us with the Identified Use Name and the relevant Use Descriptors.

Boundary composition table.

Are there other forms of molybdenum disulfide?:

Yes, there is naturally-occurring molybdenum disulfide which is exempt from REACH-registration, according to Annex V (page 5, point 7).
Importantly, both these forms are manufactured in/imported into the EU.  Because there are a couple of scientifically relevant differences in characterization of each form, it is important to have the different forms clearly and distinctly identified for the purpose of REACH-registration.

The aim, of benefit to all market participants, is to prevent confusion and uncertainty at the level of downstream users, customs/transport authorities, and in the context of REACH enforcement by EU Member State inspectors.

Source of data for REACH-registration dossier for chemically-produced MoS2:

Read-across from naturally-occurring MoS2 data is used where appropriate because chemically-produced MoS2 is not produced in isolation, meaning there is no physical substance for testing purposes.  Data from existing literature and studies on aspects of chemically-produced MoS2 are also used.  Of particular relevance is the high specific surface area of chemically-produced MoS2 that facilitates a capacity to self-heat in normal atmosphere.

Matching substance identity to an appropriate EINECS or CAS number for REACH-registration:

There are three EINECS numbers that relate to molybdenum disulfide, and it is important to determine which one most adequately corresponds to chemically-produced MoS2:

(Pre)-SIEF No. EINECS Substance name, number, molecular formula and description
Corresponding CAS name,number,molecular formula and description
1 Name: Molybdenum disulphide (MoS2)
Number: 215-263-9
Molecular formula: MoS2
Description: not available
Name: Molybdenum Sulphide (MoS2)
Number: 1317-33-5
Molecular formula: MoS2
Description: molybdenum sulphide MoS2, powder, pigment, lubricant, fine powder, etc
2 Name:  Molybdenum Sulfide
Number: 235-721-1
Molecular formula: ‘not available’
Description: not available
Name: Molybdenum Sulfide
Number: 12612-50-9
Molecular formula: Mo . S
Description: molybdenum sulfide
3 Name: Molybdenite (MoS2)
Number: 215-172-4
Molecular formula: MoS2
Description: not available
Name: Molybdenite (MoS2)
Number: 1309-56-4
Molecula formula: MoS2
Description: molybdenite (MoS2), molybdenite (8CI), molybdenum ores, molybdenite

From the above, together with information from existing literature, it is reasonable to conclude that:

  •   EINECS 235-721-1 is for chemically-produced MoS2.

Likewise it is concluded that:

  •  EINECS 215-172-4 is for naturally-occurring MoS2 in the form of molybdenite ores and concentrates
  •  EINECS 215-263-9 is for naturally-occurring MoS2 prepared in the form of fine powders for lubricant applications

What does this mean in the context of REACH Pre-SIEFS and SIEFS, data-sharing and REACH-Registration?:

(For ease of reference the (Pre-)SIEFS are referred to as Green and Yellow and Turquoise, as shown by their colouring above):

  •  Pre-registrants in the GREEN Pre-SIEF will need to add the YELLOW Pre-SIEF substance as a similar substance to their existing pre-registration information in their REACH-IT account.  See below for guidance on how to do this.
  • The Green and Yellow Pre-SIEFS are merged in a single Yellow SIEF for data-sharing and read-across purposes.
  • The Lead Registrant REACH-registers the chemically-produced MoS2 technical dossier under Yellow SIEF EINECS 235-721-1, and co-registrants do the same with their co-registrant (joint submission) dossiers.
  • There is no reason for the Turquoise Pre-SIEF to progress to constitute a SIEF because the substance is the naturally-occurring mineral that is exempt from REACH-registration. (Furthermore, all Turquoise pre-registrants also pre-registered in the Green (Pre-)SIEF, so  no-one is left isolated only in the Turquoise Pre-SIEF).

What do I do next as a pre-registrant?

  •  If you pre-registered in the Yellow (Pre-) SIEF, no action required for SIEF formation.  Simply follow the E-mail communications you will receive from MoCon as SIEF Facilitator, and then apply for a Letter of Access that will be available from April 2012 onwards at:

  • If you pre-registered in the GREEN (Pre-)SIEF, please take action by going back into that pre-registration in your REACH-IT account and adding the YELLOW(Pre-) SIEF substance as a ‘similar substance’.  This document gives you step-by-step guidance on how to do this. Then simply follow the E-mail communications you will receive from MoCon as SIEF Facilitator, and apply for a Letter of Access that will be available from April 2012 onwards at:

  •  If you pre-registered in the Turquoise (Pre-) SIEF, use your Green or Yellow (Pre-) SIEF pre-registration instead, as above.

Useful References:


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