Gadolinium silicide SDS

SAFETY DATA SHEET

Revision Date 24-Dec-2025 Revision Number 4

This safety data sheet was created pursuant to the requirements of: US OSHA Hazard Communication Standard 2024 (29 CFR 1910.1200)

1. Identification

Product Name Gadolinium silicide

Cat No. : 36356

CAS No 12134-75-7 Synonyms No information available

Recommended Use Laboratory chemicals. Uses advised against Food, drug, pesticide or biocidal product use.

Details of the supplier of the safety data sheet

Company Thermo Fisher Scientific Chemicals, Inc. 30 Bond Street Ward Hill, MA 01835-8099 Tel: 800-343-0660 Fax: 800-322-4757

Emergency Telephone Number For information US call: 001-800-227-6701 / Europe call: +32 14 57 52 11 Emergency Number US:001-201-796-7100 / Europe: +32 14 57 52 99 CHEMTREC Tel. No. US:001-800-424-9300 / Europe:001-703-527-3887

2. Hazard(s) identification

Classification Classification according to [US] OSHA (29 CFR 1910.1200, 2024)

This product is not considered hazardous by the US OSHA Hazard Communication Standard 2024 (29 CFR 1910.1200).

Label Elements None required

Hazards not otherwise classified (HNOC) None identified

Hazards classified under paragraph (d)(1)(ii) of 1910.1200 No information available

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3. Composition/information on Ingredients

Component CAS No Weight % Gadolinium silicide (GdSi2) 12134-75-7 <=100

4. First-aid measures

Eye Contact Rinse immediately with plenty of water, also under the eyelids, for at least 15 minutes. Get medical attention.

Skin Contact Wash off immediately with plenty of water for at least 15 minutes. Get medical attention immediately if symptoms occur.

Inhalation Remove to fresh air. Get medical attention immediately if symptoms occur.

Ingestion Clean mouth with water and drink afterwards plenty of water. Get medical attention if symptoms occur.

Most important symptoms and None reasonably foreseeable. effects Notes to Physician Treat symptomatically

5. Fire-fighting measures

Unsuitable Extinguishing Media No information available

Flash Point No information available Method - No information available

Autoignition Temperature No information available Explosion Limits Upper No data available Lower No data available Sensitivity to Mechanical Impact No information available Sensitivity to Static Discharge No information available

Specific Hazards Arising from the Chemical Keep product and empty container away from heat and sources of ignition.

Hazardous Combustion Products None known. Protective Equipment and Precautions for Firefighters As in any fire, wear self-contained breathing apparatus pressure-demand, MSHA/NIOSH (approved or equivalent) and full protective gear.

NFPA Health Flammability Instability Physical hazards 0 0 0 -

6. Accidental release measures

Personal Precautions Ensure adequate ventilation. Use personal protective equipment as required. Avoid dust formation. Environmental Precautions Should not be released into the environment. See Section 12 for additional Ecological Information.

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Methods for Containment and Clean Sweep up and shovel into suitable containers for disposal. Avoid dust formation. Up

7. Handling and Storage

Handling Wear personal protective equipment/face protection. Ensure adequate ventilation. Avoid contact with skin, eyes or clothing. Avoid ingestion and inhalation. Avoid dust formation.

Storage. Keep containers tightly closed in a dry, cool and well-ventilated place.

8. Exposure controls / personal protection

Exposure Guidelines This product does not contain any hazardous materials with occupational exposure limitsestablished by the region specific regulatory bodies.

Engineering Measures None under normal use conditions.

Personal Protective Equipment

Eye/face Protection Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166.

Skin and body protection Wear appropriate protective gloves and clothing to prevent skin exposure.

Respiratory Protection No protective equipment is needed under normal use conditions.

Recommended Filter type: Particle filter.

Hygiene Measures Handle in accordance with good industrial hygiene and safety practice.

9. Physical and chemical properties

Appearance Physical State Solid Pieces Color Odor Odorless Odor Threshold No information available Property Values Remarks •Method Melting Point/Range No data available Softening Point No data available Boiling Point/Range No information available Flash Point No information available Method - No information available Flammability (liquid) Not applicable Solid Flammability (solid,gas) No information available Explosion Limits No data available

Autoignition Temperature No data available Decomposition Temperature No data available pH No information available Viscosity Not applicable Solid Water Solubility No information available Solubility in other solvents No information available Partition Coefficient (n-octanol/water) Vapor Pressure No data available Density / Specific Gravity No data available

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Bulk Density No data available Vapor Density Not applicable Solid Particle characteristics No data available

Other Information Molecular Formula GdSi2 Molecular Weight 213.42 Evaporation Rate Not applicable - Solid

10. Stability and reactivity

Reactive Hazard None known, based on information available

Stability Stable under normal conditions.

Conditions to Avoid Incompatible products.

Incompatible Materials Strong oxidizing agents

Hazardous Decomposition Products None under normal use conditions

Hazardous Polymerization Hazardous polymerization does not occur.

Hazardous Reactions None under normal processing.

11. Toxicological information

Information on expected route of exposure

Inhalation Not an expected route of exposure. Ingestion No known effect based on information supplied. Eyes Not an expected route of exposure. Skin No known effect based on information supplied.

Toxicology data for the components

Toxicologically Synergistic No information available Products

(b) skin corrosion/irritation; No data available

(c) serious eye damage/irritation; No data available

(d) respiratory or skin sensitization; Respiratory No data available Skin No data available

(e) germ cell mutagenicity; No data available

(f) carcinogenicity;

The table below indicates whether each agency has listed any ingredient as a carcinogen

Component CAS No IARC NTP ACGIH OSHA Mexico Gadolinium silicide 12134-75-7 Not listed Not listed Not listed Not listed Not listed (GdSi2)

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(g) reproductive toxicity; No data available

(h) STOT-single exposure; No data available

(i) STOT-repeated exposure; No data available

Target Organs No information available.

(j) aspiration hazard; Not applicable Solid

Symptoms / effects,both acute and No information available. delayed

Other Adverse Effects The toxicological properties have not been fully investigated.

Endocrine Disrupting Properties This product does not contain any known or suspected endocrine disruptors.

12. Ecological information

Ecotoxicity Do not empty into drains.

Persistence and Degradability No information available

Bioaccumulation/ Accumulation No information available.

Mobility No information available.

13. Disposal considerations

Waste Disposal Methods Chemical waste generators must determine whether a discarded chemical is classified as a hazardous waste. Chemical waste generators must also consult local, regional, and national hazardous waste regulations to ensure complete and accurate classification.

14. Transport information

DOT Not regulated TDG Not regulated IATA Not regulated IMDG/IMO Not regulated

15. Regulatory Information

United States of America Inventory

Component CAS No TSCA TSCA Inventory notification - TSCA - EPA Regulatory Active-Inactive Flags Gadolinium silicide (GdSi2) 12134-75-7 X INACTIVE -

Legend: TSCA US EPA (TSCA) - Toxic Substances Control Act, (40 CFR Part 710) X - Listed '-' - Not Listed

TSCA - Per 40 CFR 751, Regulation of Certain Chemical Not applicable

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Substances & Mixtures, Under TSCA Section 6(h) (PBT)

TSCA 12(b) - Notices of Export Not applicable

International Inventories Canada (DSL/NDSL), Europe (EINECS/ELINCS/NLP), Philippines (PICCS), Japan (ENCS), Japan (ISHL), Australia (AICS), China (IECSC), Korea (KECL).

Component CAS No DSL NDSL EINECS PICCS ENCS ISHL AICS IECSC KECL Gadolinium silicide (GdSi2) 12134-75-7 - X 235-216-6 - - - - KE-05-0664

KECL - NIER number or KE number (http://ncis.nier.go.kr/en/main.do)

U.S. Federal Regulations

SARA 313

Section 313 of Title III of the Superfund Amendments and Reauthorization Act of 1986 (SARA). This product does not contain any

chemicals which are subject to the reporting requirements of the Act and Title 40 of the Code of Federal Regulations, Part 372

SARA 311/312 Hazard Categories Should this product meet EPCRA 311/312 Tier reporting criteria at 40 CFR 370, refer to Section 2 of this SDS for appropriate classifications.

CWA (Clean Water Act) Not applicable

Clean Air Act Not applicable

OSHA - Occupational Safety and Not applicable Health Administration

CERCLA This material, as supplied, does not contain any substances regulated as hazardous substances under the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) (40 CFR 302) or the Superfund Amendments and Reauthorization Act (SARA) (40 CFR 355). There may be specific reporting requirements at the local, regional, or state level pertaining to releases of this material.

California Proposition 65 This product does not contain any Proposition 65 chemicals.

U.S. State Right-to-Know Not applicable Regulations

U.S. Department of Transportation Reportable Quantity (RQ): N DOT Marine Pollutant N DOT Severe Marine Pollutant N

U.S. Department of Homeland This product does not contain any DHS chemicals. Security

Other International Regulations

Mexico - Grade No information available

Authorisation/Restrictions according to EU REACH Not applicable

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Component CAS No REACH (1907/2006) - REACH (1907/2006) - REACH Regulation (EC Annex XIV - Substances Annex XVII - Restrictions 1907/2006) article 59 - Subject to Authorization on Certain Dangerous Candidate List of Substances Substances of Very High Concern (SVHC) Gadolinium silicide (GdSi2) 12134-75-7 - - -

Safety, health and environmental regulations/legislation specific for the substance or mixture

Component CAS No OECD HPV Persistent Organic Ozone Depletion Restriction of Pollutant Potential Hazardous Substances (RoHS) Gadolinium silicide (GdSi2) 12134-75-7 Not applicable Not applicable Not applicable Not applicable

Contains component(s) that meet a 'definition' of per & poly fluoroalkyl substance (PFAS)? Not applicable

Other International Regulations

Component CAS No Seveso III Directive Seveso III Directive Rotterdam Basel Convention (2012/18/EC) - (2012/18/EC) - Convention (PIC) (Hazardous Waste) Qualifying Quantities Qualifying Quantities for Major Accident for Safety Report Notification Requirements Gadolinium silicide (GdSi2) 12134-75-7 Not applicable Not applicable Not applicable Not applicable

16. Other Information

Prepared By Health, Safety and Environmental Department Email: chem.techinfo@thermofisher.com www.thermofisher.com

Revision Date 24-Dec-2025 Print Date 24-Dec-2025 Revision Summary UpdatedtotheU.S.DepartmentofLabor’sOccupationalSafetyandHealthAdministration (OSHA) which published its Final Rule in the Federal Register revising the Hazard Communication Standard (HCS/HazCom), 29 CFR 1910.1200 (2024) (HCS §1910.1200, 2024), May 20, 2024, effective July 19, 2024.

Disclaimer The information provided in this Safety Data Sheet is correct to the best of our knowledge, information and belief at the date of its publication. The information given is designed only as a guidance for safe handling, use, processing, storage, transportation, disposal and release and is not to be considered a warranty or quality specification. The information relates only to the specific material designated and may not be valid for such material used in combination with any other materials or in any process, unless specified in the text

End of SDS

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