 Elemental antimony adopts a layered structure ( space group R3m No. 166 ) in which layers consist of fused ruffled six @-@ membered rings . The nearest and next @-@ nearest neighbors form an irregular octahedral complex , with the three atoms in the same double layer being slightly closer than the three atoms in the next . This relatively close packing leads to a high density of 6 @.@ 697 g / cm3 , but the weak bonding between the layers leads to the low hardness and brittleness of antimony . 
 Elemental antimony <a href='uninflect' title='1'><mark>adopts</mark></a> a layered structure ( space group R3m No. 166 ) in which layers consist of fused ruffled six @-@ membered rings . The nearest and next @-@ nearest neighbors form an irregular octahedral complex , with the three atoms in the same double layer being slightly closer than the three atoms in the next . This relatively close packing leads to a high density of 6 @.@ 697 g / cm3 , but the weak bonding between the layers <a href='uninflect' title='2'><mark>leads</mark></a> to the low hardness and brittleness of antimony . 
Elemental antimony adopt a layered structure ( space group R3m No. 166 ) in which layers consist of fused ruffled six @-@ membered rings . da nearest and nxt @-@ nearest neighbors form an irregular octahedral complex , with tdathree atoms in the same double layer being slightly closer than thdahree atoms in the next . dis relatively close packing leads to a high density of 6 @.@ 697 g / cm3 , but thedaak bonding between the daers lead to the ldahardness and brittleness of antimony .