Boron

boron

kernite

borax

colemanite

Formula: B
Element, metalloid, does not occur in the native state on Earth, although it has been identified from the moon
Specific gravity: 2.34
Colour: Black
Solubility: Insoluble in nitric and hydrochloric acids
Melting point: 2075oC
Boiling point: 3727oC
Abundance in the Earth’s crust: 10 parts per million by mass, 1 part per million by moles
Abundance in the Solar System: 2 parts per billion by mass, 0.2 parts per billion by moles
Boron compounds are usually found in sediments and sedimentary rock formations. The chief sources of boron are kernite, borax and colemanite. In compounds boron almost always occurs as trivalent B3+ (ChC)

Boron-bearing minerals include:

Borides - borides are usually covalent rather than ionic
jingsuiite

Fluorides - the fluoride anion is F-
avogadrite
barberiite

Monoborates - with a single boron anion (BO3)3- or B(O,OH)4


bandylite
berborite
bonaccordite
chiyokoite
fluoborite
folvikite
fredrikssonite
frolovite
gaudefroyite
hambergite
hulsite
hydroxylborite
jeremejevite
jimboite
kotoite
ludwigite
nordenskiöldine
pseudosinhalite
rhabdoborite-(Mo)
rhabdoborite-(V)
rhabdoborite-(W)
sakhaite
sibirskite
sinhalite
takedaite
vonsenite
warwickite

Diborates - with double boron triangles and/or tetrahedra
calciborite
parasibirskite
pentahydroborite
suanite
sussexite
szaibélyite
wiserite

Triborates
colemanite
howlite
hydroboracite
inderborite
inderite
inyoite
kurnakovite
meyerhofferite
nifontovite
olshanskyite

Tetraborates
borax
borcarite
kernite
tincalconite

Pentaborates
gowerite
hilgardite
priceite
probertite
ulexite
volkovskite

Hexaborates
strontioginorite
tunellite

Heptaborates
boracite
congolite
ericaite
trembathite

Nonaborates
studenitsite

Sulphates - the sulphate anion is (SO4)2-
tatarinovite

Phosphates - the phosphate anion is (P5+O4)3-
seamanite

Nesosilicates
arrheniusite-(Ce)
cappelenite-(Y)
grandidierite
hellandite-(Y)
melanocerite-(Ce)
ominelite
stillwellite-(Ce)

Sorosilicate - (Si4+2O7)6- groups
boralsilite
kornerupine
tinzenite
werdingite

Cyclosilicates - (Si4+nO3n)2n- groups
alumino-oxy-rossmanite
chromium-dravite
darrellhenryite
dravite
fluor-buergerite
fluor-dravite
fluor-liddicoatite
fluor-schorl
fluor-uvite
magnesio-foitite
maruyamaite
oxy-chromium-dravite
oxy-dravite
oxy-schorl
princivalleite
schorl
tienshanite
titantaramellite

Inosilicates - single chain - (Si4+nO3n)2n- groups
hellandite-(Ce)
serendibite

Phyllosilicates - (Si4+2O5)2- groups
leucosphenite
oyelite
searlesite

Tectosilicate - [Al3+xSi4+OyO(2x+2y)]x−
lisitsynite

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