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About Tantalum

Tantalum Bohr

Tantalum is extremely chemically similar to niobium; the two exist neither as free elements on earth nor independent from each other, present in minerals like tantalite, columbite, samarskite , microlite, wodginite, euxenite, fergusonite, and polycrase. The minerals called tantalite and columbite (alternately, niobate) actually have the same chemical structure, the two names reflecting a difference in relative proportion of tantalum to niobium. The history of the two elements is similarly entwined. In 1801, British chemist and mineralogist Charles Hatchett became intrigued by a mineral sample displayed in the collection that had been sent decades earlier from the American colonies by Connecticut governor John Winthrop. His analysis of the sample yielded a substance he believed contained a heretofore undiscovered element that he named “columbium” for Columbia, the symbolic female embodiment of the United States, and the mineral itself came to be called columbite. Less than a year later in Uppsala, Sweden, chemist Anders Gustaf Ekeberg suspected he had discovered a new element by similarly extracting an oxide form from tantalite. This oxide proved so highly resistant to attack by even acid that he named the element “tantalum” after the Greek mythological figure of Tantalus, who remained unable to quench his thirst from the water in which he stood. Later that year, however, British chemist William Hyde Wollaston declared that columbium and tantalum were in fact the same element (despite the difference in density between the two oxide forms), and that tantalum should be its official name.

Much confusion ensued in the following years within the scientific community. In 1845, German chemist Heinrich Rose posited that tantalite contained two additional elements besides tantalum, naming them “pelopium” and “niobium” after Pelops and Niobe, the mythological daughters of Tantalus; in 1847, R. Hermann announced that he had discovered a new element, “ilmenium,” from the mineral samarskite. Pelopium and ilmenium were subsequently shown to be mixes of tantalum and and niobium. The difference between tantalum and niobium was not empirically proven until the 1860’s by Jean Charles Galissard de Marignac, and pure tantalum was not isolated until 1903 by Werner von Bolton. For years, the standard method for separating the two elements was achieved via de Marignac’s method of fractional crystallization; later methods developed include liquid-liquid extraction from aqueous solutions of fluoride compounds and a modified version of the Hall-Héroult electrolysis technique based on powdered oxides.

Elemental tantalum is a lustrous blue-gray transition metal that is a member of the heat-resistant refractory metal group. Naturally occurring tantalum has two isotopes; metastable 180m-Ta is both the only naturally-occurring nuclear isomer and is also calculated to be the rarest primordial isotope in the universe. Tantalum metal is hard and dense, yet also ductile and highly malleable; its resistance to corrosion is similar to that of glass and the highest of any metal in common use. An extremely thin and stable surface film of tantalum pentoxide provides the metal with its surface passivation: it is essentially chemically inert at temperatures below 150 C and resists attack by all acids except hydrofluoric acid, fluoride-containing acidic solutions, and oleum (sulfur trioxide in sulfuric acid solution). This stability and non-reactivity with body tissue or fluids makes it useful for chemical and pharmaceutical components, laboratory instruments, and medical implants, especially as a more cost-effective substitute for platinum and other precious metals. Tantalum has one of the highest melting points of all elements, surpassed only by tungsten, rhenium, osmium, and carbon, yet it is also highly conductive to heat and electricity. Coupled with its extreme resistance to corrosion, these properties make tungsten a critical industrial metal for applications in high-temperature oxidizing environments like linings of nuclear reactors, aircraft components, rocket engines, vacuum furnace and heat exchanger installations, and chemical processing equipment. The metal was also used in early lamp filaments and radio transmitter electron tubes for this reason. Tantalum alloys and superalloys are extremely dense, strong, and durable, with high melting points and excellent machinability that are utilized by the aerospace, nuclear, defense, and hot metal-working industries. Other significant industrial materials are tantalum nitrides and tantalum carbides: hard, durable, and highly heat-resistant ceramics materials used in cutting tools, jet engine and turbine blades, and drill bits. A tantalum carbide-graphite composite material developed by scientists at the Los Alamos National Lab has been labeled one of the hardest materials ever synthesized.

The most prevalent commercial use of metallic tantalum is in the compact, high-performance capacitors of electronics such as mobile devices, digital cameras, laptop computers, pacemakers, GPS systems, and anti-lock braking systems. Because dielectric coatings of tantalum pentoxide are thinner than their aluminum corollary, tantalum-based capacitors are lighter and more efficient, in addition to being highly reliable with low leakage and excellent capacity. Materials like tantalum nitride have also been used in thin-chip resistors and as copper diffusion barriers in micro- and nanoelectronic devides. Other applications for tantalum have emerged in advanced technology. Lithium tantalate (LiTaO3) is a ferroelectric perovskite crystal used in non-linear optics, and the high refractive index of tantalum oxide is utilized in optical coatings and metallic glass. In addition, the metal’s excellent resistance to corrosion and heat make it an attractive cost-effective alternative to platinum or gold in fuel cell collector plates and in the extreme environments required for production of alternative energy sources like biofuels.

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Tantalum has a number of interesting properties that make it particularly useful in electronic applications. It has the third highest melting point, surpassed only by rhenium and tungsten, yet it is highly conductive to heat and electricity. This has made it the material of choice for the electronic capacitors used in most telecommunications and hand held electronics equipment, such as cell phones, laptop computers and pagers. Tantalum compounds, such as tantalum oxide and tantalum chloride, are the basis for dielectric coatings. High Purity (99.999%) Tantalum Oxide (Ta2O5) PowderTantalum is added to glass for its high refractive index. It also has various applications in nuclear energy. Tantalum is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include tamtalum pellets, rod, wire and granules for evaporation source material purposes. High Purity (99.999%) Tantalum Sputtering Target Tantalum nanoparticles and nanopowders provide ultra-high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Tantalum is also available in soluble forms including chloride, nitrate, and acetate. These compounds can be manufactured as solutions at specified stoichiometries.

Tantalum Properties

Tantalum(Ta) atomic and molecular weight, atomic number and elemental symbolTantalum is a Block D, Group 5, Period 6 element. The number of electrons in each of tantalum's shells is 2, 8, 18, 32, 11, 2 and its electron configuration is [Xe] 4f14 5d3 6s2. Tantalum Bohr ModelThe tantalum atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-25-7, tantalum has a gray blue appearance. High Purity (99.999%) Tantalum (Ta) MetalTantalum is found in the minerals tantalite, microlite, wodginite, euxenite, and polycrase. Tantalum was first discovered by Anders G. Ekeberg in 1802 in Uppsala, Sweden. Due to the close relation of tantalum to niobium in the periodic table, Tantalum's name originates from the Greek word Tantalos, meaning Father of Niobe in Greek mythology.

Symbol: Ta
Atomic Number: 73
Atomic Weight: 180.9479
Element Category: transition metal
Group, Period, Block: 5, 6, d
Color: gray blue
Other Names: Tantale, Tantal, Tántalo
Melting Point: 3017 °C, 5463 °F, 3290 K
Boiling Point: 5458 °C, 9856 °F, 5731 K
Density: 16.69 g·cm3
Liquid Density @ Melting Point: 15 g·cm3
Density @ 20°C: 16.6 g/cm3
Density of Solid: 16650 kg·m3
Specific Heat: 0.14 (kJ/kg K)
Superconductivity Temperature: 4.47 [or -268.68 °C (-451.62 °F)] K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 31.4
Heat of Vaporization (kJ·mol-1): 758.22
Heat of Atomization (kJ·mol-1): 781.425
Thermal Conductivity: 57.5 W·m-1·K-1
Thermal Expansion: (25 °C) 6.3 µm·m-1·K-1
Electrical Resistivity: (20 °C) 131 nΩ·m
Tensile Strength: N/A
Molar Heat Capacity: 25.36 J·mol-1·K-1
Young's Modulus: 186 GPa
Shear Modulus: 69 GPa
Bulk Modulus: 200 GPa
Poisson Ratio: 0.34
Mohs Hardness: 6.5
Vickers Hardness: 873 MPa
Brinell Hardness: 800 MPa
Speed of Sound: (20 °C) 3400 m·s-1
Pauling Electronegativity: 1.5
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.33
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.5
Reflectivity (%): 78
Refractive Index: N/A
Electrons: 73
Protons: 73
Neutrons: 108
Electron Configuration: [Xe] 4f14 5d3 6s2
Atomic Radius: 146 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 170±8 pm
Covalent Radius (Å): 1.58
Van der Waals Radius: 200 pm
Oxidation States: 5, 4, 3, 2, -1 (mildly acidic oxide)
Phase: Solid
Crystal Structure: body-centered cubic
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 31.057
1st Ionization Energy: 761 kJ·mol-1
2nd Ionization Energy: 1500 kJ·mol-1
3rd Ionization Energy: N/A
CAS Number: 7440-25-7
EC Number: 231-135-5
MDL Number: MFCD00011252
Beilstein Number: N/A
SMILES Identifier: [Ta]
InChI Identifier: InChI=1S/Ta
PubChem CID: 23956
ChemSpider ID: 22395
Earth - Total: 23.3 ppb 
Mercury - Total: 17.9 ppb
Venus - Total: 24.4 ppb
Earth - Seawater (Oceans), ppb by weight: 0.002
Earth - Seawater (Oceans), ppb by atoms: 0.000068
Earth -  Crust (Crustal Rocks), ppb by weight: 1700
Earth -  Crust (Crustal Rocks), ppb by atoms: 190
Sun - Total, ppb by weight: N/A
Sun - Total, ppb by atoms: N/A
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: 20
Meterorite (Carbonaceous), ppb by atoms: 2
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 0.08
Universe, ppb by atom: 0.0006
Discovered By: Anders Gustaf Ekeberg
Discovery Date: 1802
First Isolation: N/A

Health, Safety & Transportation Information for Tantalum

Tantalum is not toxic in its elemental form; however, safety data for Tantalum and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Tantalum.

Safety Data
Signal Word N/A
Hazard Statements N/A
Hazard Codes N/A
Risk Codes N/A
Safety Precautions N/A
RTECS Number N/A
Transport Information N/A
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)
Review and Print SDS for Tantalum Metal


Date Created: 05/15/2015
Date Revised: 05/15/2015


Product Name: Tantalum Metal

Product Number: All applicable American Elements product codes, e.g. TA-M-02, TA-M-03, TA-M-04, TA-M-05

CAS #: 7440-25-7

Relevant identified uses of the substance: Scientific research and development

Supplier details:
American Elements
1093 Broxton Ave. Suite 2000
Los Angeles, CA 90024
Tel: +1 310-208-0551
Fax: +1 310-208-0351

Emergency telephone number:
Domestic, North America +1 800-424-9300
International +1 703-527-3887


Classification of the substance or mixture
Classification according to Regulation (EC) No 1272/2008
The substance is not classified as hazardous to health or the environment according to the CLP regulation.
Classification according to Directive 67/548/EEC or Directive 1999/45/EC
Not applicable
Information concerning particular hazards for human and environment:
No information known.
Hazards not otherwise classified
No information known.
Label elements
Labelling according to Regulation (EC) No 1272/2008
Not applicable
Hazard pictograms
Not applicable
Signal word
Not applicable
Hazard statements
Not applicable
WHMIS classification
Not controlled
Classification system
HMIS ratings (scale 0-4)
(Hazardous Materials Identification System)

Health (acute effects) = 0
Flammability = 0
Physical Hazard = 0
Other hazards
Results of PBT and vPvB assessment
Not applicable.
Not applicable.


Chemical characterization: Substances
CAS# Description:
7440-25-7 Tantalum
Identification number(s):
EC number:


Description of first aid measures
General information
No special measures required.
After inhalation
Seek medical treatment in case of complaints.
After skin contact
Generally the product does not irritate the skin.
After eye contact
Rinse opened eye for several minutes under running water. If symptoms persist, consult a doctor.
After swallowing
If symptoms persist consult doctor.
Information for doctor
Most important symptoms and effects, both acute and delayed
No further relevant information available.
Indication of any immediate medical attention and special treatment needed
No further relevant information available.


Extinguishing media
Suitable extinguishing agents
Special powder for metal fires. Do not use water.
For safety reasons unsuitable extinguishing agents
Special hazards arising from the substance or mixture
If this product is involved in a fire, the following can be released:
Titanium oxides
Advice for firefighters
Protective equipment:
No special measures required.


Personal precautions, protective equipment and emergency procedures
Not required.
Environmental precautions:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow product to reach sewage system or any water course.
Do not allow to penetrate the ground/soil.
Methods and material for containment and cleaning up:
Pick up mechanically
Prevention of secondary hazards:
No special measures required.
Reference to other sections
See Section 7 for information on safe handling
See Section 8 for information on personal protection equipment.
See Section 13 for disposal information.


Precautions for safe handling
Keep container tightly sealed.
Store in cool, dry place in tightly closed containers.
Information about protection against explosions and fires:
No special measures required.
Conditions for safe storage, including any incompatibilities
Requirements to be met by storerooms and receptacles:
No special requirements.
Information about storage in one common storage facility:
Not required.
Further information about storage conditions:
Keep container tightly sealed.
Store in cool, dry conditions in well sealed containers.
Specific end use(s)
No further relevant information available.


Additional information about design of technical systems:
No further data; see section 7.
Control parameters
Components with limit values that require monitoring at the workplace:
7440-25-7 Tantalum (100.0%)
PEL (USA) Long-term value: 5 mg/m³
REL (USA) Short-term value: 10 mg/m³
Long-term value: 5 mg/m³
TLV (USA) metal; TLV withdrawn due to insufficient data
EL (Canada) Long-term value: 5 mg/m³
EV (Canada) Long-term value: 10 mg/m³
metal and oxide (total dust)
Additional information: No data
Exposure controls
Personal protective equipment
General protective and hygienic measures
The usual precautionary measures for handling chemicals should be followed.
Maintain an ergonomically appropriate working environment.
Breathing equipment: Not required.
Protection of hands: Not required.
Penetration time of glove material (in minutes)
Not determined
Eye protection: Safety glasses
Body protection: Protective work clothing


Information on basic physical and chemical properties
General Information
Form: Solid in various forms
Color: Grey to silver
Odor: Odorless
Odor threshold: Not determined.
pH-value: Not applicable.
Change in condition
Melting point/Melting range: 2996 °C (5425 °F)
Boiling point/Boiling range: 5429 °C (9804 °F)
Sublimation temperature / start: Not determined
Flammability (solid, gaseous)
Not determined.
Ignition temperature: Not determined
Decomposition temperature: Not determined
Auto igniting: Not determined.
Danger of explosion: Not determined.
Explosion limits:
Lower: Not determined
Upper: Not determined
Vapor pressure: Not applicable.
Density at 20 °C (68 °F): 16.69 g/cm³ (139.278 lbs/gal)
Relative density
Not determined.
Vapor density
Not applicable.
Evaporation rate
Not applicable.
Solubility in / Miscibility with Water: Insoluble
Partition coefficient (n-octanol/water): Not determined.
dynamic: Not applicable.
kinematic: Not applicable.
Other information
No further relevant information available.


No information known.
Chemical stability
Stable under recommended storage conditions.
Thermal decomposition / conditions to be avoided:
Decomposition will not occur if used and stored according to specifications.
Possibility of hazardous reactions
No dangerous reactions known
Conditions to avoid
No further relevant information available.
Incompatible materials:
No information known.
Hazardous decomposition products:
Titanium oxides


Information on toxicological effects
Acute toxicity:
The Registry of Toxic Effects of Chemical Substances (RTECS) contains acute toxicity data for this substance.
LD/LC50 values that are relevant for classification:
No data
Skin irritation or corrosion:
No irritant effect.
Eye irritation or corrosion:
No irritant effect.
No sensitizing effects known.
Germ cell mutagenicity:
No effects known.
No classification data on carcinogenic properties of this material is available from the EPA, IARC, NTP, OSHA or ACGIH.
The Registry of Toxic Effects of Chemical Substances (RTECS) contains tumorigenic and/or carcinogenic and/or neoplastic data for this substance.
Reproductive toxicity:
No effects known.
Specific target organ system toxicity - repeated exposure:
No effects known.
Specific target organ system toxicity - single exposure:
No effects known.
Aspiration hazard:
No effects known.
Subacute to chronic toxicity:
No effects known.
Additional toxicological information:
To the best of our knowledge the acute and chronic toxicity of this substance is not fully known.


Aquatic toxicity:
No further relevant information available.
Persistence and degradability
No further relevant information available.
Bioaccumulative potential
No further relevant information available.
Mobility in soil
No further relevant information available.
Additional ecological information:
General notes:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow undiluted product or large quantities to reach ground water, water course or sewage system.
Avoid transfer into the environment.
Results of PBT and vPvB assessment
Not applicable.
Not applicable.
Other adverse effects
No further relevant information available.


Waste treatment methods
Consult state, local or national regulations to ensure proper disposal.
Uncleaned packagings:
Disposal must be made according to official regulations.


Not applicable
UN proper shipping name
Not applicable
Transport hazard class(es)
Not applicable
Packing group
Not applicable
Environmental hazards: Not applicable.
Special precautions for user
Not applicable.
Transport in bulk according to Annex II of MARPOL73/78 and the IBC Code
Not applicable.
Transport/Additional information: DOT
Marine Pollutant (DOT): No


Safety, health and environmental regulations/legislation specific for the substance or mixture
National regulations
All components of this product are listed in the U.S. Environmental Protection Agency Toxic Substances Control Act Chemical substance Inventory.
All components of this product are listed on the Canadian Domestic Substances List (DSL).
SARA Section 313 (specific toxic chemical listings)
Substance is not listed.
California Proposition 65
Prop 65 - Chemicals known to cause cancer
Substance is not listed.
Prop 65 - Developmental toxicity
Substance is not listed.
Prop 65 - Developmental toxicity, female
Substance is not listed.
Prop 65 - Developmental toxicity, male
Substance is not listed.
Information about limitation of use:
For use only by technically qualified individuals.
Other regulations, limitations and prohibitive regulations
Substance of Very High Concern (SVHC) according to the REACH Regulations (EC) No. 1907/2006.
Substance is not listed.
The conditions of restrictions according to Article 67 and Annex XVII of the Regulation (EC) No 1907/2006 (REACH) for the manufacturing, placing on the market and use must be observed.
Substance is not listed.
Annex XIV of the REACH Regulations (requiring Authorisation for use)
Substance is not listed.
REACH - Pre-registered substances
Substance is listed


Safety Data Sheet according to Regulation (EC) No. 1907/2006 (REACH). The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. American Elements shall not be held liable for any damage resulting from handling or from contact with the above product. See reverse side of invoice or packing slip for additional terms and conditions of sale. COPYRIGHT 1997-2016 AMERICAN ELEMENTS. LICENSED GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLY.

Tantalum Isotopes

Naturally occuring tantalum (Ta) has two stable isotopes: 180Ta (0.012%) and 181Ta (99.988%).

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
155Ta 154.97459(54)# 13(4) µs [12(+4-3) µs] Unknown (11/2-) N/A 1198.24 -
156Ta 155.97230(43)# 144(24) ms ß+ to 156Hf; p to 155Lu (2-) N/A 1206.32 -
157Ta 156.96819(22) 10.1(4) ms a to 153Lu; ß+ to 157Hf 1/2+ N/A 1223.71 -
158Ta 157.96670(22)# 49(8) ms a to 154Lu; ß+ to 158Hf (2-) N/A 1231.79 -
159Ta 158.963018(22) 1.04(9) s ß+ to 159Hf; a to 155Lu (1/2+) N/A 1239.87 -
160Ta 159.96149(10) 1.70(20) s a to 156Lu; ß+ to 160Hf (2#)- N/A 1247.95 -
161Ta 160.95842(6)# 3# s ß+ to 161Hf; a to 157Lu 1/2+# N/A 1265.34 -
162Ta 161.95729(6) 3.57(12) s ß+ to 162Hf; a to 158Lu 3+# N/A 1273.42 -
163Ta 162.95433(4) 10.6(18) s ß+ to 163Hf; a to 159Lu 1/2+# N/A 1281.5 -
164Ta 163.95353(3) 14.2(3) s ß+ to 164Hf (3+) N/A 1289.58 -
165Ta 164.950773(19) 31.0(15) s ß+ to 165Hf 5/2-# N/A 1297.66 -
166Ta 165.95051(3) 34.4(5) s ß+ to 166Hf (2)+ N/A 1305.74 -
167Ta 166.94809(3) 1.33(7) min ß+ to 167Hf (3/2+) N/A 1323.13 -
168Ta 167.94805(3) 2.0(1) min ß+ to 168Hf (2-,3+) N/A 1331.21 -
169Ta 168.94601(3) 4.9(4) min ß+ to 169Hf (5/2+) N/A 1339.29 -
170Ta 169.94618(3) 6.76(6) min ß+ to 170Hf (3)(+#) N/A 1347.37 -
171Ta 170.94448(3) 23.3(3) min ß+ to 171Hf (5/2-) N/A 1355.45 -
172Ta 171.94490(3) 36.8(3) min ß+ to 172Hf (3+) N/A 1363.52 -
173Ta 172.94375(3) 3.14(13) h ß+ to 173Hf 5/2- N/A 1371.6 -
174Ta 173.94445(3) 1.14(8) h ß+ to 174Hf 3+ N/A 1379.68 -
175Ta 174.94374(3) 10.5(2) h ß+ to 175Hf 7/2+ N/A 1387.76 -
176Ta 175.94486(3) 8.09(5) h ß+ to 176Hf (1)- N/A 1395.84 -
177Ta 176.944472(4) 56.56(6) h EC to 177Hf 7/2+ 2.25 1403.92 -
178Ta 177.945778(16) 9.31(3) min EC to 178Hf 1+ 2.74 1412 -
179Ta 178.9459295(23) 1.82(3) y EC to 179Hf 7/2+ N/A 1420.08 -
180Ta 179.947462 (4) Observationally Stable - 9- N/A 1428.15 -
180mTa 179.9474648(24) 8.152(6) h EC to 180Hf; ß- to 180W 1+ N/A 1444.661743 0.012
181Ta 180.9479958(19) Observationally Stable - 7/2+ 2.371 1436.23 99.988
182Ta 181.9501518(19) 114.43(3) d ß- to 182W 3- 3.02 1435 -
183Ta 182.9513726(19) 5.1(1) d ß- to 183W 7/2+ 2.36 1443.07 -
184Ta 183.954008(28) 8.7(1) h ß- to 184W (5-) N/A 1451.15 -
185Ta 184.955559(15) 49.4(15) min ß- to 185W (7/2+)# N/A 1459.23 -
186Ta 185.95855(6) 10.5(3) min ß- to 186W (2-,3-) N/A 1467.31 -
187Ta 186.96053(21)# 2# min [>300 ns] ß- to 187W 7/2+# N/A 1466.07 -
188Ta 187.96370(21)# 20# s [>300 ns] ß- to 188W N/A N/A 1474.15 -
189Ta 188.96583(32)# 3# s [>300 ns] Unknown 7/2+# N/A 1482.23 -
190Ta 189.96923(43)# 0.3# s Unknown N/A N/A 1490.31 -