arsenic pentoxide

arsenic pentoxide

formula | As_2O_5 name | arsenic pentoxide alternate names | arsenic acid anhydride | arsenic anhydride | arsenic(V) oxide | diarsenic pentaoxide mass fractions | As (arsenic) 65.2% | O (oxygen) 34.8%

Draw the Lewis structure of arsenic pentoxide. Start by drawing the overall structure of the molecule, ignoring potential double and triple bonds: Count the total valence electrons of the arsenic (n_As, val = 5) and oxygen (n_O, val = 6) atoms: 2 n_As, val + 5 n_O, val = 40 Calculate the number of electrons needed to completely fill the valence shells for arsenic (n_As, full = 8) and oxygen (n_O, full = 8): 2 n_As, full + 5 n_O, full = 56 Subtracting these two numbers shows that 56 - 40 = 16 bonding electrons are needed. Each bond has two electrons, so in addition to the 6 bonds already present in the diagram we expect to add 2 bonds. To minimize formal charge oxygen wants 2 bonds. Identify the atoms that want additional bonds and the number of electrons remaining on each atom: Add 2 bonds by pairing electrons between adjacent highlighted atoms. Additionally, atoms with large electronegativities can minimize their formal charge by forcing atoms with smaller electronegativities on period 3 or higher to expand their valence shells. The electronegativities of the atoms are 2.18 (arsenic) and 3.44 (oxygen). Because the electronegativity of arsenic is smaller than the electronegativity of oxygen and the electronegativity of {} is smaller than the electronegativity of {}, expand the valence shell of arsenic to 5 bonds in 2 places and expand the valence shell of {} to {} bonds. Therefore we add a total of 4 bonds to the diagram: Answer: | |

molar mass | 229.84 g/mol phase | solid (at STP) melting point | 300 °C density | 4.09 g/cm^3

density | 4.09 g/cm^3

specific heat capacity c_p | solid | 0.5069 J/(g K) molar heat capacity c_p | solid | 116.5 J/(mol K) specific free energy of formation Δ_fG° | solid | -3.404 kJ/g molar free energy of formation Δ_fG° | solid | -782.3 kJ/mol specific heat of formation Δ_fH° | solid | -4.024 kJ/g molar heat of formation Δ_fH° | solid | -924.9 kJ/mol molar heat of fusion | 60 kJ/mol | specific heat of fusion | 0.3 kJ/g | (at STP)

CAS number | 1303-28-2 PubChem CID number | 14771 PubChem SID number | 24871878 SMILES identifier | O=[As](=O)O[As](=O)=O InChI identifier | InChI=1/As2O5/c3-1(4)7-2(5)6 RTECS number | CG2275000 MDL number | MFCD00003434

NFPA label

lethal dosage | 8 mg/kg (oral dose for rats)