mhchem (24jul15)

git-svn-id: svn://tug.org/texlive/trunk@37943 c570f23f-e606-0410-a88d-b1316a301751

5 files changed, 172 insertions, 142 deletions

diff --git a/Master/texmf-dist/doc/latex/mhchem/README b/Master/texmf-dist/doc/latex/mhchem/README
index 4a258578407..c1b53441e32 100644
--- a/Master/texmf-dist/doc/latex/mhchem/README
+++ b/Master/texmf-dist/doc/latex/mhchem/README
@@ -1,7 +1,7 @@
-The mhchem Bundle 2015-04-23
+The mhchem Bundle 2015-07-23
 
 containing
-- mhchem v4.01
+- mhchem v4.02
 - hpstatement v1.01
 - rsphrase v3.11
 
diff --git a/Master/texmf-dist/doc/latex/mhchem/manifest.txt b/Master/texmf-dist/doc/latex/mhchem/manifest.txt
index f008046fef7..3835c77fe2d 100644
--- a/Master/texmf-dist/doc/latex/mhchem/manifest.txt
+++ b/Master/texmf-dist/doc/latex/mhchem/manifest.txt
@@ -1,6 +1,7 @@
 This work consists of the files
 
   mhchem.sty      (Copyright Martin Hensel)
+  mhchem.4ht      (Copyright Martin Hensel)
   hpstatement.sty (Copyright Martin Hensel, except the contained statements)
   rsphrase.sty    (Copyright Martin Hensel, except the contained phrases)
   
diff --git a/Master/texmf-dist/doc/latex/mhchem/mhchem.pdf b/Master/texmf-dist/doc/latex/mhchem/mhchem.pdf
index 5d642912e4a..db4fea48dd1 100644
--- a/Master/texmf-dist/doc/latex/mhchem/mhchem.pdf
+++ b/Master/texmf-dist/doc/latex/mhchem/mhchem.pdf
diff --git a/Master/texmf-dist/doc/latex/mhchem/mhchem.tex b/Master/texmf-dist/doc/latex/mhchem/mhchem.tex
index bc1e4c827f4..03fea5234d3 100644
--- a/Master/texmf-dist/doc/latex/mhchem/mhchem.tex
+++ b/Master/texmf-dist/doc/latex/mhchem/mhchem.tex
@@ -67,7 +67,7 @@
   The mhchem Bundle\\[0.3em]
   \Large\textmd{%
     Documentation for the Packages\\
-    mhchem v4.01,\\% check
+    mhchem v4.02,\\% check
     hpstatement v1.01 and\\
     rsphrase v3.11}%
 }
@@ -76,7 +76,7 @@
   mhchem\makebox[0pt][l]{\textcolor{white}{NOSPAM}}@MartinHensel\makebox[1pt][l]{\textcolor{white}{.}}.de%
 }
 \date{%
-  2015-04-23% check
+  2015-07-23% check
 }
 \maketitle
 
@@ -132,7 +132,7 @@ mhchem needs a couple of other packages. For instance, expl3, amsmath and calc.
 \end{SideBySideExample}
 
 \begin{SideBySideExample}[xrightmargin=6cm]
-  \ce{Hg^2+ ->[I-] HgI2 
+  \ce{Hg^2+ ->[I-] HgI2
             ->[I-] [Hg^{II}I4]^2-}
 \end{SideBySideExample}
 
@@ -391,7 +391,7 @@ You can `half-escape' to math by using \verb|$...$|. Remember, that the math fon
 When `half-escaped', mhchem tries to recognize common patterns and still use the correct font.
 
 \begin{SideBySideExample}[xrightmargin=4cm]
-  $\ce{Fe^$n$+}$ \sffamily\bfseries \ce{Fe^$n$+} 
+  $\ce{Fe^$n$+}$ \sffamily\bfseries \ce{Fe^$n$+}
 \end{SideBySideExample}
 
 You can prevent this recognition by `fully escaping' to math with \verb|${...}$|.
@@ -761,7 +761,7 @@ switches back to the default, which is equivalent to
 
 \subsection{Greek Font} \label{sec:GreekFont}
 
-If you load a package for upright Greek letters, this will automatically be used. This was possible by the very neat chemgreek package of Clemens Niederberger. If you want to have different Greek fonts for text mode and math mode, you can specify these `mappings', e.\,g. by \verb|\mhchemoptions{text-greek=upgreek,| \verb|math-greek=default}|. You can use any of 
+If you load a package for upright Greek letters, this will automatically be used. This was possible by the very neat chemgreek package of Clemens Niederberger. If you want to have different Greek fonts for text mode and math mode, you can specify these `mappings', e.\,g. by \verb|\mhchemoptions{text-greek=upgreek,| \verb|math-greek=default}|. You can use any of
 \begin{compactitem}[--]
   \item default,
   \item var-default,
@@ -825,6 +825,10 @@ If you use this switch inside your document with \macro{mhchemoptions}, don't fo
 
 
 
+\section{Rudimentary \TeX 4HT (htlatex) support}
+
+mhchem has basic support for \TeX 4HT (htlatex). Summary formulae should work fine. Special bonds and reaction arrows are recognizable, but ugly. Complex math with mhchem inside might fail completely.
+
 \clearpage
 \section{Major Changes}
 \label{sec:WhatSNew}
@@ -844,9 +848,16 @@ Meaning and usage of \macro{bond} changed.
 
 \section{Most Recent Changes}% check
 
+\minisec{2015-07-23 mhchem v4.02}
+\begin{compactitem}
+\item added rudimentary TeX4ht support
+\item fixed the \verb|\str_case:nnn| bug---expl3 removed that function
+\end{compactitem}
+
 \minisec{2015-04-23 mhchem v4.01}
 \begin{compactitem}
-\item syntax improvements% $n$H2O, D2-3[T4O10], Fe^{III}2 
+\item support upright greek characters (chemgreek)
+\item syntax improvements% $n$H2O, D2-3[T4O10], Fe^{III}2
 \item recognition of states of aggregation% HCl(g), OH-(aq)
 \item text-font operators \verb|+|, \verb|-|, \verb|=|
 \end{compactitem}
diff --git a/Master/texmf-dist/tex/latex/mhchem/mhchem.sty b/Master/texmf-dist/tex/latex/mhchem/mhchem.sty
index 5d27ecce7ce..f9d1fe25f25 100644
--- a/Master/texmf-dist/tex/latex/mhchem/mhchem.sty
+++ b/Master/texmf-dist/tex/latex/mhchem/mhchem.sty
@@ -27,7 +27,7 @@
 % This work consists of all files listed in manifest.txt.
 %
 %
-\ProvidesPackage{mhchem}[2015/04/23 v4.01 for typesetting chemical formulae]
+\ProvidesPackage{mhchem}[2015/07/23 v4.02 for typesetting chemical formulae]
 \RequirePackage{expl3}
 \RequirePackage{l3keys2e}
 \RequirePackage{l3regex}
@@ -55,7 +55,7 @@
 \ExplSyntaxOn
 
 \cs_generate_variant:Nn \str_if_eq:nnTF { Vn }
-\cs_generate_variant:Nn \str_case:nnn { Vnn }
+\cs_generate_variant:Nn \str_case:nnF { VnF }
 \cs_generate_variant:Nn \regex_match:nnTF { nV }
 \cs_generate_variant:Nn \regex_match:nnTF { no }
 \cs_new_protected:Npn \__mhchem_regex_peek:nTF #1 #2 #3
@@ -85,7 +85,7 @@
   }
 \cs_new_protected:Npn \__mhchem_loopHelper_appendNextGroup_prefix_ifEmpty:NnnNn #1#2#3#4#5
   {
-    \str_if_eq:nnTF {#5} {}
+    \tl_if_empty:nTF {#5}
       { #3 }
       { \tl_put_right:Nn #1 { #2 { #5 } } }
     #4
@@ -174,9 +174,9 @@
 %%%%%%%%%%
 %%% /\ %%%
 
-%%%%%%%%%%%%%%%%%%%%%%%%%5%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%   \cesplit   %%%%%%%%%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%5%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \ExplSyntaxOn
 
 \cs_generate_variant:Nn \regex_replace_all:nnN { VnN }
@@ -362,20 +362,22 @@
     \int_set:Nn \l__mhchem_ce_distanceFromLastComma_int { 9 }
     \tl_clear:N \l__mhchem_cf_lastElement_tl
     \__mhchem_ce_loop: #1 \q_recursion_stop
+    \__mhchem_output_begin_ce:
     \int_compare:nTF { \l__mhchem_option_version_int > 1 }
       { \tl_use:N \l__mhchem_ce_result_tl }
       { \ensuremath{\tl_use:N \l__mhchem_ce_result_tl} }
+    \__mhchem_output_end_ce:
     \mhchem@hook@afterCe
     \group_end:
   }
 \cs_new_protected:Npn \__mhchem_ce_loop:
   {
     \int_incr:N \l__mhchem_ce_distanceFromLastComma_int
-    \str_case:Vnn \l__mhchem_ce_state_tl
+    \str_case:VnF \l__mhchem_ce_state_tl
       {
         { c }
           {
-            \str_case:Vnn \l__mhchem_ce_part_tl
+            \str_case:VnF \l__mhchem_ce_part_tl
               {
                 { + }
                   {
@@ -435,7 +437,7 @@
       {
         \__mhchem_ce_output:
       }{
-    \str_case:Vnn \l__mhchem_ce_state_tl
+    \str_case:VnF \l__mhchem_ce_state_tl
       {
         { c }
           {
@@ -524,7 +526,7 @@
               }
             % else
               {
-                \str_case:Vnn \l__mhchem_ce_arrowName_tl
+                \str_case:VnF \l__mhchem_ce_arrowName_tl
                   {
                     { yieldsLeft }
                       {
@@ -739,11 +741,11 @@
 \cs_new_protected:Npn \__mhchem_ce_output:
   {
     \bool_set_true:N \l__mhchem_ce_potentialSpacingAllowed_bool
-    \str_case:Vnn \l__mhchem_ce_state_tl
+    \str_case:VnF \l__mhchem_ce_state_tl
       {
         { c }
           {
-            \str_case:Vnn \l__mhchem_ce_part_tl
+            \str_case:VnF \l__mhchem_ce_part_tl
               {
                 { - }
                   {
@@ -757,12 +759,6 @@
                       { \__mhchem_output_operatorEquals: }
                     \bool_set_false:N \l__mhchem_ce_potentialSpacingAllowed_bool
                   }
-                { +- }
-                  {
-                    \tl_put_right:Nn \l__mhchem_ce_result_tl
-                      { \__mhchem_output_operatorPlusMinus: }
-                    \bool_set_false:N \l__mhchem_ce_potentialSpacingAllowed_bool
-                  }
                 { $\pm$ }
                   {
                     \tl_put_right:Nn \l__mhchem_ce_result_tl
@@ -965,7 +961,7 @@
   }
 \cs_new_protected:Npn \__mhchem_arrow_deploy:nnnnn #1#2#3#4#5
   {
-    \str_case:nnn {#2}
+    \str_case:nnF {#2}
       {
         {  }
           {
@@ -1443,25 +1439,23 @@
 \cs_new_protected:Npn \__mhchem_cf:nn #1#2
   {
     \group_begin:
-    \let\sbond\__mhchem_output_sbond:
-    \int_compare:nTF { 2 = \l__mhchem_option_version_int }
-      { \let\bond\sbond }
+    \bool_if:NF \l__mhchem_cf_cfActive_bool
       {
-        \int_compare:nT { \l__mhchem_option_version_int > 2 }
+        \bool_set_true:N \l__mhchem_cf_cfActive_bool
+        \bool_if:NF \l__mhchem_ce_ceActive_bool
+          { \__mhchem_output_defMathOrText: }
+        \int_compare:nTF { \l__mhchem_option_version_int < 3 }
+          { \cs_set_eq:NN \bond \__mhchem_output_bond_single: }
           {
-            \def\bond{\mhchem@bond}
+            \cs_set_protected:Npn \bond { \mhchem@bond }
           }
-      }
-    \def\dbond{\rlap{\protect\raisebox{.2ex}{\sbond}}\protect\raisebox{-.2ex}{\sbond}}
-    \def\tbond{\rlap{\protect\raisebox{.4ex}{\sbond}}
-      \rlap{\sbond}\protect\raisebox{-.4ex}{\sbond}}
-    \def\hyphen{\mhchem@hyphen}
-    \bool_if:NF \l__mhchem_ce_ceActive_bool {
-      \bool_if:NF \l__mhchem_cf_cfActive_bool
-        {
-          \bool_set_true:N \l__mhchem_cf_cfActive_bool
-          \__mhchem_output_defMathOrText:
-        }
+        \int_compare:nT { \l__mhchem_option_version_int < 4 }
+          {
+            \cs_set_protected:Npn \sbond { \__mhchem_output_bond_single: }
+            \cs_set_protected:Npn \dbond { \__mhchem_output_bond_double: }
+            \cs_set_protected:Npn \tbond { \__mhchem_output_bond_triple: }
+          }
+        \cs_set_protected:Npn \hyphen {\mhchem@hyphen}
       }
     \tl_set:Nn \l__mhchem_cf_state_tl { s }
     \bool_set_false:N \l__mhchem_cf_startedWithBond_bool
@@ -1474,9 +1468,11 @@
         \tl_clear:N \l__mhchem_cf_result_tl
         \__mhchem_cf_loop: #2 \q_recursion_stop
       }
-      \str_if_eq:nnTF {#1} {}
+      \__mhchem_output_begin_cf:
+      \tl_if_empty:nTF {#1}
         { \ensuremath{\tl_use:N \l__mhchem_cf_result_tl} }
         { \ensuremath{\overset{#1}{\tl_use:N \l__mhchem_cf_result_tl}} }
+      \__mhchem_output_end_cf:
     \group_end:
   }
 \tl_new:N \l__mhchem_cf_loop_tmpa_l
@@ -1487,14 +1483,14 @@
   {
     \peek_meaning_remove:NTF \q_recursion_stop
       {
-        \str_case:Vnn \l__mhchem_cf_state_tl
+        \str_case:VnF \l__mhchem_cf_state_tl
           {
             { - }
               {
                 \bool_if:NTF \l__mhchem_cf_startedWithBond_bool
                   {
                     \__mhchem_cf_outputAndReset:
-                    \__mhchem_cf_outputRawElementAndReset:n { \sbond }
+                    \__mhchem_cf_outputRawElementAndReset:n { \__mhchem_output_bond_single: }
                   }
                   { \tl_put_right:Nn \l__mhchem_cf_sup_tl { - } }
               }
@@ -1508,7 +1504,7 @@
       { \__mhchem_loopHelper_ignoreNextToken:Nn \__mhchem_cf_loop: }{
     \peek_meaning:NTF \protect
       { \__mhchem_loopHelper_ignoreNextToken:Nn \__mhchem_cf_loop: }{
-    \str_case:Vnn \l__mhchem_cf_state_tl
+    \str_case:VnF \l__mhchem_cf_state_tl
       {
         { - }
           {
@@ -1521,7 +1517,8 @@
                   { \__mhchem_cg_escapeFromMathToTextOrFaketext:n { - } }
               }
               {
-                \__mhchem_cf_outputRawElementAndReset:n { \sbond }
+                \__mhchem_cf_outputRawElementAndReset:n
+                  { \__mhchem_output_bond_single: }
               }
             \tl_set:Nn \l__mhchem_cf_state_tl { s }
             \__mhchem_cf_loop:
@@ -1622,7 +1619,7 @@
               {
                 \__mhchem_cf_outputAndReset:
                 \__mhchem_loopHelper_outputAndReset_appendToResult_setState_useNone:nnNn
-                  { \dbond }
+                  { \__mhchem_output_bond_double: }
                   { s }
                   \__mhchem_cf_loop:
               }{
@@ -1630,7 +1627,7 @@
               {
                 \__mhchem_cf_outputAndReset:
                 \__mhchem_loopHelper_outputAndReset_appendToResult_setState_useNone:nnNn
-                  { \tbond }
+                  { \__mhchem_output_bond_triple: }
                   { s }
                   \__mhchem_cf_loop:
               }{
@@ -1833,14 +1830,14 @@
             \peek_charcode:NTF =
               {
                 \__mhchem_loopHelper_outputAndReset_appendToResult_setState_useNone:nnNn
-                  { \dbond }
+                  { \__mhchem_output_bond_double: }
                   { s }
                   \__mhchem_cf_loop:
               }{
             \peek_charcode:NTF ##
               {
                 \__mhchem_loopHelper_outputAndReset_appendToResult_setState_useNone:nnNn
-                  { \tbond }
+                  { \__mhchem_output_bond_triple: }
                   { s }
                   \__mhchem_cf_loop:
               }{
@@ -2179,17 +2176,16 @@
             ! \tl_if_empty_p:N \l__mhchem_cf_sub_tl  ||
             ! \tl_if_empty_p:N \l__mhchem_cf_sup_tl
           }
-        \str_case:Vnn \l__mhchem_cf_state_tl
+        \str_case:VnF \l__mhchem_cf_state_tl
           {
             { 1 }
               {
                 \__mhchem_cg_replaceForAmount:N \l__mhchem_cf_element_tl
                 \tl_put_right:Nx \l__mhchem_cf_result_tl
                   {
-                    \exp_not:N \__mhchem_output_withFont:n {
+                    \exp_not:N \__mhchem_output_amount:n {
                     \exp_not:V \l__mhchem_cf_element_tl
                     }
-                    \exp_not:N \__mhchem_output_skipAfterAmount:
                   }
               }
             { 9 }
@@ -2225,10 +2221,10 @@
             \bool_if:nT
               {
                 \str_if_eq_p:Vn \l__mhchem_cf_supState_tl { kv }  &&
-                \str_if_eq_p:Vn \l__mhchem_cf_sub_tl {}
+                \tl_if_empty_p:V \l__mhchem_cf_sub_tl
               }
               { \tl_set:Nn \l__mhchem_cf_supState_tl { d } }
-            \str_case:Vnn \l__mhchem_cf_supState_tl
+            \str_case:VnF \l__mhchem_cf_supState_tl
               {
                 { kv }
                   {
@@ -2600,7 +2596,7 @@
       }{
     \peek_charcode_remove:NTF .
       {
-        \str_case:Vnn \l__mhchem_cg_replaceForSuperscript_state_tl
+        \str_case:VnF \l__mhchem_cg_replaceForSuperscript_state_tl
           {
             { 9. }
               {
@@ -2654,7 +2650,7 @@
       }{
     \peek_charcode_remove:NTF ,
       {
-        \str_case:Vnn \l__mhchem_cg_replaceForSuperscript_state_tl
+        \str_case:VnF \l__mhchem_cg_replaceForSuperscript_state_tl
           {
             { 9. }
               {
@@ -2708,16 +2704,27 @@
         \mhchem@option@textFont
       }
   }
+
+\cs_new_protected:Npn \__mhchem_output_begin_ce: {}
+\cs_new_protected:Npn \__mhchem_output_end_ce: {}
+\cs_new_protected:Npn \__mhchem_output_begin_cf: {}
+\cs_new_protected:Npn \__mhchem_output_end_cf: {}
+
+\cs_new_protected:Npn \__mhchem_output_amount:n #1
+  {
+    \__mhchem_output_withFont:n {#1}
+    \__mhchem_output_skipAfterAmount:
+  }
 \cs_new_protected:Npn \__mhchem_output_coreFive:nnnnnnn #1#2#3#4#5#6#7
   {
     \group_begin:
     \bool_if:nT
-      { \str_if_eq_p:nn {#7} {}  &&  ! \str_if_eq_p:nn {#5} {} }
+      { \tl_if_empty_p:n {#7}  &&  ! \tl_if_empty_p:n {#5} }
       { \bool_set_true:N \l__mhchem_option_superscriptsStacked_bool }
     \m@th
     \ensuremath
       {
-        \str_if_eq:nnF {#1#2} {}
+        \tl_if_empty:nF {#1#2}
           {
             \hphantom { {}^{\__mhchem_output_withFont:n{#1}}\c_math_subscript_token{\__mhchem_output_withFont:n{#2}} }
             { \vphantom { \__mhchem_output_withFont:n { X } } }
@@ -2728,7 +2735,7 @@
                     \__mhchem_output_scriptWithFont:n {#1}
                   }
               }
-            \str_if_eq:nnF {#2} {}
+            \tl_if_empty:nF {#2}
               {
                 \c_math_subscript_token {
                   \mhchem@mathboxrightt
@@ -2740,12 +2747,12 @@
             \mhchem@minispace
           }
         \__mhchem_output_withFont:n {#3}
-        \str_if_eq:nnF {#4#5#6#7} {}
+        \tl_if_empty:nF {#4#5#6#7}
           {
             \bool_if:NTF \l__mhchem_option_superscriptsStacked_bool
               {
                 { \vphantom { \__mhchem_output_withFont:n { X } } }
-                \str_if_eq:nnF {#6} {}
+                \tl_if_empty:nF {#6}
                   {
                     \c_math_subscript_token
                       {
@@ -2762,7 +2769,7 @@
               {
                 \bool_if:NTF \l__mhchem_option_subscriptsDeep_bool
                   {
-                    \str_if_eq:nnF {#4} {}
+                    \tl_if_empty:nF {#4}
                       {
                         { \vphantom { \__mhchem_output_withFont:n { X } } }
                         ^ {
@@ -2774,10 +2781,10 @@
                             \vphantom { \__mhchem_output_scriptWithFont:n { 2 } }
                           }
                       }
-                    \str_if_eq:nnF {#5#6#7} {}
+                    \tl_if_empty:nF {#5#6#7}
                       {
                         { \vphantom { \__mhchem_output_withFont:n { X } } }
-                        \str_if_eq:nnF {#6} {}
+                        \tl_if_empty:nF {#6}
                           {
                             \c_math_subscript_token
                               {
@@ -2793,14 +2800,14 @@
                       }
                   }
                   {
-                    \str_if_eq:nnF {#4} {}
+                    \tl_if_empty:nF {#4}
                       {
                         { \vphantom { \__mhchem_output_withFont:n { X } } }
                         ^ {
                             \__mhchem_output_scriptWithFont:n {#4}
                           }
                       }
-                    \str_if_eq:nnF {#6} {}
+                    \tl_if_empty:nF {#6}
                       {
                         { \vphantom { \__mhchem_output_withFont:n { X } } }
                         \c_math_subscript_token
@@ -2809,7 +2816,7 @@
                             \smash[t] { \__mhchem_output_scriptWithFont:n {#6} }
                           }
                       }
-                    \str_if_eq:nnF {#5#7} {}
+                    \tl_if_empty:nF {#5#7}
                       {
                         { \vphantom { \__mhchem_output_withFont:n { X } } }
                         ^ {
@@ -2887,12 +2894,6 @@
       { - }
       { \mhchem@option@textminus }
   }
-\cs_new_protected:Npn \__mhchem_output_plus:
-  {
-    \bool_if:NTF \l__mhchem_output_isMathMode_bool
-      { {}+{} }
-      { \hspace{0.5ex minus 0.5ex} + \hspace{0.5ex minus 0.5ex} }
-  }
 \cs_new_protected:Npn \__mhchem_output_operatorPlus:
   {
     \int_compare:nTF { \l__mhchem_option_version_int < 4 }
@@ -2964,6 +2965,61 @@
       { \__mhchem_output_commaEnumerationSmall: }
   }
 
+\cs_new_protected:Npn \__mhchem_output_bond_single:
+  {
+    \int_compare:nTF { \l__mhchem_option_version_int < 4 }
+      { {\ensuremath{-}} }
+      {
+        \bool_if:NTF \l__mhchem_output_isMathMode_bool
+          { {\ensuremath{-}} }
+        { \text{\mhchem@option@textminus} }
+      }
+  }
+\cs_new_protected:Npn \__mhchem_output_bond_double:
+  {
+    \rlap { \protect \raisebox { .2ex }{ \__mhchem_output_bond_single: } }
+    \protect \raisebox { -.2ex }{ \__mhchem_output_bond_single: }
+  }
+\cs_new_protected:Npn \__mhchem_output_bond_triple:
+  {
+    \rlap { \protect \raisebox { .4ex } { \__mhchem_output_bond_single: } }
+    \rlap{ \__mhchem_output_bond_single: }
+    \protect \raisebox { -.4ex } { \__mhchem_output_bond_single: }
+  }
+\cs_new_protected:Npn \__mhchem_output_bond_half:
+  {
+    \mhchem@setbondwidth
+    \mhchem@halfbond
+  }
+\cs_new_protected:Npn \__mhchem_output_bond_oneAndHalf:
+  {
+    \mhchem@setbondwidth
+    \rlap{\protect\raisebox{.2ex}{\mhchem@halfbond}}
+    \protect\raisebox{-.2ex}{\__mhchem_output_bond_single:}
+  }
+\cs_new_protected:Npn \__mhchem_output_bond_twoAndHalf:
+  {
+    \mhchem@setbondwidth
+    \rlap{\protect\raisebox{.4ex}{\mhchem@halfbond}}
+    \rlap{\__mhchem_output_bond_single:}
+    \protect\raisebox{-.4ex}{\__mhchem_output_bond_single:}
+  }
+\cs_new_protected:Npn \__mhchem_output_bond_twoAndHalff:
+  {
+    \mhchem@setbondwidth
+    \rlap{\protect\raisebox{.4ex}{\__mhchem_output_bond_single:}}
+    \rlap{\mhchem@halfbond}
+    \protect\raisebox{-.4ex}{\__mhchem_output_bond_single:}
+  }
+\cs_new_protected:Npn \__mhchem_output_bond_dotdotdot:
+  { {\cdot}{\cdot}{\cdot} }
+\cs_new_protected:Npn \__mhchem_output_bond_dotdotdotdot:
+ { {\cdot}{\cdot}{\cdot}{\cdot} }
+\cs_new_protected:Npn \__mhchem_output_bond_rightArrow:
+  { {\rightarrow} }
+\cs_new_protected:Npn \__mhchem_output_bond_leftArrow:
+  { {\leftarrow} }
+
 \cs_new_protected:Npn \__mhchem_output_greek:n #1
   {
     \group_begin:
@@ -3050,89 +3106,51 @@
           \setlength\mhchem@bondtmp@minussidebearingright{\mhchem@option@minustextsidebearingright}
         }
     }
-  \setlength\mhchem@bondwidth{\widthof{\sbond}}%
-  \setlength\mhchem@bondheight{\heightof{\sbond}}%
+  \setlength\mhchem@bondwidth{\widthof{\__mhchem_output_bond_single:}}%
+  \setlength\mhchem@bondheight{\heightof{\__mhchem_output_bond_single:}}%
   \setlength\mhchem@smallbondwidth@tmpA{%
     \mhchem@bondwidth-\mhchem@bondtmp@minussidebearingleft-\mhchem@bondtmp@minussidebearingright}%
   \setlength\mhchem@smallbondwidth@tmpB{%
-    \widthof{\sbond\sbond\sbond}-\mhchem@bondtmp@minussidebearingleft-%
+    \widthof{\__mhchem_output_bond_single:\__mhchem_output_bond_single:\__mhchem_output_bond_single:}-\mhchem@bondtmp@minussidebearingleft-%
     \mhchem@bondtmp@minussidebearingright}%
   \setlength\mhchem@smallbondwidth{\mhchem@bondwidth*%
     \ratio{\mhchem@smallbondwidth@tmpA}{\mhchem@smallbondwidth@tmpB}}%
 }
 \def\mhchem@halfbond{\rlap{\hspace{\mhchem@bondtmp@minussidebearingleft}%
-                     \resizebox{\mhchem@smallbondwidth}{\mhchem@bondheight}{\sbond}\unskip%
-                     \resizebox{\mhchem@smallbondwidth}{\mhchem@bondheight}{\sbond}%
-                     \resizebox{\mhchem@smallbondwidth}{\mhchem@bondheight}{\sbond}}%
-                     \phantom{\sbond}}%
-
-\cs_new_protected:Npn \__mhchem_output_sbond:
-  {
-    \int_compare:nTF { \l__mhchem_option_version_int < 4 }
-      { {\ensuremath{-}} }
-      {
-        \bool_if:NTF \l__mhchem_output_isMathMode_bool
-          { {\ensuremath{-}} }
-        { \text{\mhchem@option@textminus} }
-      }
-  }
+                     \resizebox{\mhchem@smallbondwidth}{\mhchem@bondheight}{\__mhchem_output_bond_single:}\unskip%
+                     \resizebox{\mhchem@smallbondwidth}{\mhchem@bondheight}{\__mhchem_output_bond_single:}%
+                     \resizebox{\mhchem@smallbondwidth}{\mhchem@bondheight}{\__mhchem_output_bond_single:}}%
+                     \phantom{\__mhchem_output_bond_single:}}%
 
+\msg_new:nnn { mhchem } { bond / unknown }
+  { Unknown~bond~type~in~\string\bond~(#1) }
 \ExplSyntaxOff
-
 \ExplSyntaxOn % with special tilde
 \char_set_catcode_letter:n { 126 } % tilde
-
 \cs_new_protected:Npn \mhchem@bond #1
   {
     \ensuremath
       {
-        \str_case:nnn {#1}
-          {
-            { - } { \sbond }
-            { 1 } { \sbond }
-            { = } { \dbond }
-            { 2 } { \dbond }
-            { ## } { \tbond }
-            { 3 } { \tbond }
-            { ~ }
-              {
-                \mhchem@setbondwidth
-                \mhchem@halfbond
-              }
-            { ~- }
-              {
-                \mhchem@setbondwidth
-                \rlap{\protect\raisebox{.2ex}{\mhchem@halfbond}}
-                \protect\raisebox{-.2ex}{\sbond}
-              }
-            { ~-- }
-              {
-                \mhchem@setbondwidth
-                \rlap{\protect\raisebox{.4ex}{\mhchem@halfbond}}
-                \rlap{\sbond}
-                \protect\raisebox{-.4ex}{\sbond}
-              }
-            { ~= }
-              {
-                \mhchem@setbondwidth
-                \rlap{\protect\raisebox{.4ex}{\mhchem@halfbond}}
-                \rlap{\sbond}
-                \protect\raisebox{-.4ex}{\sbond}
-              }
-            { -~- }
-              {
-                \mhchem@setbondwidth
-                \rlap{\protect\raisebox{.4ex}{\sbond}}
-                \rlap{\mhchem@halfbond}
-                \protect\raisebox{-.4ex}{\sbond}
-              }
-            { ... } { {\cdot}{\cdot}{\cdot} }
-            { .... } { {\cdot}{\cdot}{\cdot}{\cdot} }
-            { -> } { {\rightarrow} }
-            { <- } { {\leftarrow} }
-          }
-          {
-            \PackageError{mhchem}{Unknown~bond~type~in~\string\bond~(#1)}%
+        \str_case:nnF {#1}
+          {
+            { - } { \__mhchem_output_bond_single: }
+            { 1 } { \__mhchem_output_bond_single: }
+            { = } { \__mhchem_output_bond_double: }
+            { 2 } { \__mhchem_output_bond_double: }
+            { ## } { \__mhchem_output_bond_triple: }
+            { 3 } { \__mhchem_output_bond_triple: }
+            { ~ } { \__mhchem_output_bond_half: }
+            { ~- } { \__mhchem_output_bond_oneAndHalf: }
+            { ~-- } { \__mhchem_output_bond_twoAndHalf: }
+            { ~= } { \__mhchem_output_bond_twoAndHalf: }
+            { -~- } { \__mhchem_output_bond_twoAndHalff: }
+            { ... } { \__mhchem_output_bond_dotdotdot: }
+            { .... } { \__mhchem_output_bond_dotdotdotdot: }
+            { -> } { \__mhchem_output_bond_rightArrow: }
+            { <- } { \__mhchem_output_bond_leftArrow: }
+          }
+          {
+            \msg_error:nnx { mhchem } { bond / unknown } {#1}
           }
       }
   }