The atomic masses of the two stable isotopes of boron, boron-10 (19.78 percent) and boron-11 (80.22 percent), are 10.0129 amu and 11.0093 amu respectively.

Further data for naturally occuring isotopes of boron are listed above. This table gives information about some radiosotopes of boron, their masses, their half-lives, their modes of decay, their nuclear spins, and their nuclear magnetic moments. Isotope Mass / Da Half-life Mode of decay Nuclear spin Nuclear magnetic moment; 8 B: 8.024607: 0.770 s. A boron atom has 5 protons and 5 electrons. Its average atomic mass is 10.81. Natural boron consists of a mix of two stable isotopes: boron-10 and boron-11. Eleven isotopes, with masses 7 to 17 are known. Boron exhibits properties of either metals or nonmetals, depending on the conditions. Download sketchup make 2016 mac. Name: Boron Symbol: B Atomic Number: 5 Atomic Mass: 10.811 amu Melting Point: 2300.0 °C (2573.15 K, 4172.0 °F) Boiling Point: 2550.0 °C (2823.15 K, 4622.0 °F) Number of Protons/Electrons: 5 Number of Neutrons: 6 Classification: Metalloid Crystal Structure: Rhombohedral Density @ 293 K: 2.34 g/cm 3 Color: brownish Atomic Structure.

In 1961, the Commission recommended A_r(B) = 10.811(3) based on calibrated mass-spectrometricmeasurements on brines and minerals from Searles Lake. The uncertainty was based on reported variations in natural abundances. In 1981, the Commission concluded that the range of isotope-abundance variations typical of themost common sources is covered by A_r(B) = 10.811(2). This value includes major commercial sourcesof boron in California and Turkey. However, the existence of normal terrestrial occurrences with sampleatomic weights outside these implied limits could not be denied. Under the 1983 policy of a moreliberal use of any single-digit uncertainty, the Commission changed the recommended standard atomic weightto A_r(B) = 10.811(5). In 1985, the 'g' annotation was added to reflect the occurrence of materials with anomalous isotopic compositions. Compared with most other standard atomic weights, the tabulated value for boron is relatively uncertain. That uncertainty increased in 1995 when the Commission decided to include the isotopic composition of boron in seawater.

Natural variations in n(¹¹B)/n(¹⁰B) are reported as δ¹¹B values relative to the reference materialNIST SRM 951a, which has n(¹¹B)/n(¹⁰B) = 4.0437(33). Reported δ¹¹B_951a values range from a low of −34.2 ‰ (x(¹¹B) = 0.7961 and A_r(B) = 10.8062) in a metamorphicmineral sample from Antarctica to a high of +59.2 ‰ (x(¹¹B) = 0.8107 andA_r(B) = 10.8207) in brine from a volcanic crater lake in south-eastern Australia. Separated and enrichedisotopes of boron are commercially available; the atomic weights of such samples can differ fromone another by up to almost 10 %. Although the Commission is unaware of undisclosed commercial sales ofsuch material, an 'm' annotation warns users of the possibility of its inadvertent dissemination.

Boron Atomic Mass 11

CIAAW

Boron
A_r(B) = [10.806, 10.821] since 2009
The name derives from the Arabic buraq for 'white'. Although its compounds were known for thousandsof years, it was not isolated until 1808 by the French chemists Louis-Joseph Gay-Lussac and Louis-Jacques Thenard.

Natural variations of boron isotopic composition

Boron Atomic Mass Formula

Isotopic reference materials of boron.