Co-
crys
talli
satio
n of
Ene
rget
ic M
ater
ials
: HM
X
Ene
rget
ic m
ater
ials
Ene
rget
ic m
ater
ials
can
be
split
into
thre
e gr
oups
: exp
losi
ves,
pro
pella
nts
and
pyro
tech
nics
, with
exp
losi
ves
furt
her
divi
ded
into
prim
ary
and
seco
ndar
y ex
plos
ives
. The
re is
cur
rent
ly a
driv
e to
war
ds d
ecre
asin
g th
e se
nsiti
vity
of e
nerg
etic
mat
eria
ls w
ith th
e ai
m o
f pro
duci
ng
inse
nsiti
ve m
uniti
ons,
i.e.
exp
losi
ves
that
are
saf
er to
use
.
The
ene
rget
ic m
ater
ial i
nves
tigat
ed in
this
stu
dy is
HM
X, a
sec
onda
ry e
xplo
sive
wid
ely
used
in m
ilita
ry a
pplic
atio
ns.
HM
X h
as th
ree
know
n po
lym
orph
s �
, �an
d �
, and
a h
emih
ydra
te k
now
n as
the �
form
. T
he �
form
is th
e m
ost s
tabl
e at
roo
m te
mpe
ratu
re a
nd th
e le
ast s
ensi
tive
to a
ccid
enta
l ini
tiatio
n.
The
mol
ecul
es a
dopt
a c
hair
type
con
form
atio
n in
the �
poly
mor
ph w
hile
in th
e �
, �an
d �
form
s it
adop
ts a
boa
t typ
e co
nfor
mat
ion.
Co-
crys
talli
satio
n
A c
o-cr
ysta
l is
a cr
ysta
l tha
t con
tain
s tw
o or
mor
e ne
utra
l com
pone
nts
in a
sto
ichi
omet
ric r
atio
.
The
prin
cipl
es o
f sup
ram
olec
ular
syn
thes
is c
an b
e ap
plie
d to
the
desi
gn o
f co-
crys
tals
, esp
ecia
lly th
e us
e of
sup
ram
olec
ular
he
tero
synt
hons
.Thi
sis
term
ed c
ryst
al e
ngin
eerin
g.
The
co-
crys
talli
satio
n of
caf
fein
e is
an
exam
ple
whe
re c
o-cr
ysta
llisa
tion
has
succ
essf
ully
bee
n us
ed in
the
phar
mac
eutic
alin
dust
ry. T
he c
o-cr
ysta
llisa
tion
of c
affe
ine
with
oxa
lic a
cid
was
foun
d to
red
uce
the
abso
rptio
n of
wat
er w
hen
com
pare
d to
pur
e ca
ffein
e.3
Co-
crys
tals
of H
MX
1:1
HM
X:3
-Met
hyl-2
-oxa
zolid
inon
e co
-cry
stal
1:2
HM
X:1
,2-D
imet
hylim
idaz
ole
co-c
ryst
al
0
500
1000
1500
2000
2500
3000
3500
4000
0500
1000
1500
2000
250
0300
035
0040
00
cm
-1
Trim
eth
ylur
azol
e
delta
-HM
X
Co-c
rysta
l
beta
-HM
X
NN
NO
O
Me
Me
Me
��
�
��
�
Mol
ecul
ar c
onfo
rmat
ion
foun
d in
�H
MX
1M
olec
ular
con
form
atio
n fo
und
in �
, �an
d �
HM
X2
Cry
stal
logr
aphi
c D
ata
For
mul
a���������������
Spa
ce g
roup
P-1
Uni
t ce
ll pa
ram
eter
sa
8.05
62(3
) Å
b11
.181
5(4)
Åc
12.7
430(
4) Å
�
107.
1160
(10)
�
90.3
390(
10)
�
93.7
160(
10)
Vol
ume
1094
.37
Å3
Z2
R-f
acto
r4.
3%
0
1000
2000
3000
4000
0500
1000
15
00
2000
2500
300
03
500
4000
cm
-1
1,2
-dim
eth
ylim
idaz
ole
de
lta-H
MX
Co-c
rys
tal
be
ta-H
MX
0
1000
2000
3000
4000
0500
1000
1500
2000
2500
3000
3500
4000
cm
-1
3-m
eth
yl-2-o
xazolidin
one
delta-H
MX
Co-c
rysta
l
beta
-HM
X
Cry
stal
logr
aphi
c D
ata
For
mul
a������ ������ ��
Spa
ce g
roup
C2
/c
Uni
t ce
ll pa
ram
eter
sa
26.
8357
(8)
Åb
15.2
883(
4) Å
c11
.931
1(4)
Å
�
90
�
104.
531(
3)
�
90V
olum
e47
38.4
2 Å
3
Z10
R-f
acto
r7.
9%
Fut
ure
Wor
k
Det
erm
inin
g th
e se
nsiti
vity
of t
he c
o-cr
ysta
ls to
acc
iden
tal i
nitia
tion,
e.g
. dr
op w
eigh
t tes
ts
D
esig
n of
ene
rget
ic c
o-fo
rmer
s to
giv
e co
-cry
stal
s w
ith le
ss p
enal
ty to
the
ener
getic
per
form
ance
.
S
cale
up
of th
e pr
oduc
tion
of th
e co
-cry
stal
s to
allo
w fo
r la
rger
sca
le
perf
orm
ance
and
sta
bilit
y te
stin
g
Co-
form
er D
esig
n
Ref
eren
ces
1 C
.S.C
hoi,
H.P
.Bou
tin, A
cta
Cry
sta
llog
r.,S
ect.
B:S
truct.
Cry
sta
llogr.
Cry
st.C
he
m.,
1970
, 26,
1235
2 R
.E.C
obbl
edic
k, R
.W.H
.Sm
all,
Acta
Cry
sta
llog
r.,S
ect.
B:S
truct.
Cry
sta
llog
r.C
ryst.
Ch
em
., 1
978,
30
, 191
8
3 V
. Tra
sk, W
. D. S
. Mot
herw
ell,
and
W. J
ones
,Cry
st. G
row
th &
Desig
n, 2
005,
5, 1
013
Kno
wn
co-f
orm
ers
Ram
an s
pect
rum
of t
he c
o-cr
ysta
l of H
MX
and
1,2
-D
imet
hylim
idaz
ole
com
pare
d to
thos
e of
the
pure
co
mpo
unds
Ram
an s
pect
rum
of t
he c
o-cr
ysta
l of H
MX
and
3-M
ethy
l-2-
oxaz
olid
inon
e co
mpa
red
to th
ose
of th
e pu
re c
ompo
unds
Ram
an s
pect
rum
of t
he c
o-cr
ysta
l of H
MX
and
Trim
ethy
lura
zole
com
pare
d to
thos
e of
the
pure
com
poun
ds
3-M
ethy
l-2-
oxaz
olid
inon
eN
-met
hylp
yrro
lidon
e
Dim
ethy
lform
amid
e1,
3-D
imet
hylim
idaz
olid
inon
e
Com
mon
Fea
ture
Trim
ethy
lura
zole
Cry
stal
logr
aphi
c da
ta fo
r th
e 1:
2 H
MX
:1,2
-D
imet
hylim
idaz
ole
co-c
ryst
al
Cry
stal
logr
aphi
c da
ta fo
r th
e 1:
1 H
MX
:3-M
ethy
l-2-
oxaz
olid
inon
e C
o-cr
ysta
l
A p
roje
ctio
n of
the
pack
ing
of th
e co
-cry
stal
alo
ng th
e a
crys
tallo
grap
hic
axis
sho
win
g th
e la
yere
d st
ruct
ure
A p
roje
ctio
n of
the
pack
ing
of th
e co
-cry
stal
alo
ng th
e b
crys
tallo
grap
hic
axis
sho
win
g th
e la
yere
d st
ruct
ure
A p
roje
ctio
n of
the
pack
ing
of th
e co
-cry
stal
alo
ng th
e c
crys
tallo
grap
hic
axis
sho
win
g th
e la
yere
d st
ruct
ure
A p
roje
ctio
n of
the
pack
ing
of th
e co
-cry
stal
alo
ng th
e b
crys
tallo
grap
hic
axis
sho
win
g th
e la
yere
d st
ruct
ure
The
asy
met
ricun
it of
the
co-
crys
tal s
how
ing
the
HM
X
mol
ecul
e in
the �
type
co
nfor
mat
ion
The
asy
met
ricun
it of
the
co-
crys
tal s
how
ing
the
HM
X
mol
ecul
e in
the �
type
co
nfor
mat
ion
Cra
ig A
. Hen
ders
on a
nd C
olin
R. P
ulha
m
Com
mon
exa
mpl
e of
sup
ram
olec
ular
syn
thon
s.T
he a
sym
etric
unit
of th
e ca
ffein
e:ox
alic
acid
co-
crys
tal
Des
igne
d m
olec
ule
Edi
nbur
gh a
nd S
t And
rew
s R
esea
rch
Sch
ool o
f Che
mis
try
(EaS
tChe
m)
Sch
ool o
f Che
mis
try,
Uni
vers
ity o
f Edi
nbur
gh, J
osep
h B
lack
Bui
ldin
g, W
est M
ains
Roa
d, E
dinb
urgh
, Sco
tland
EH
9 3J
J
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